Merge bitcoindevkit/bdk#1437: Bump bdk version to 1.0.0-alpha.11

db9fdccc18 Bump bdk version to 1.0.0-alpha.11 (Steve Myers)

Pull request description:

  ### Description

  fixes #1435

  bdk_chain to 0.14.0
  bdk_bitcoind_rpc to 0.10.0
  bdk_electrum to 0.13.0
  bdk_esplora to 0.13.0
  bdk_file_store to 0.11.0
  bdk_testenv to 0.4.0
  bdk_persist to 0.2.0

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

ACKs for top commit:
  ValuedMammal:
    ACK db9fdccc18
  storopoli:
    ACK db9fdccc18

Tree-SHA512: 804475927461a4bcf37786313123a0a0cc68390af6c556111551dc126a06614296eb657a8a5662a36cf4569ab332f5f9285c99c5f1992d93f43568e881961895

.github/workflows/code_coverage.yml

@@ -33,7 +33,7 @@ jobs:
       - name: Run simulator image
         run: docker run --name simulator --network=host hwi/ledger_emulator &
       - name: Install Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v4
         with:
           python-version: '3.9'
       - name: Install python dependencies

.github/workflows/cont_integration.yml

@@ -12,7 +12,7 @@ jobs:
         rust:
           - version: stable
             clippy: true
-          - version: 1.57.0 # MSRV
+          - version: 1.63.0 # MSRV
         features:
           - --no-default-features
           - --all-features
@@ -28,28 +28,12 @@ jobs:
       - name: Rust Cache
         uses: Swatinem/rust-cache@v2.2.1
       - name: Pin dependencies for MSRV
-        if: matrix.rust.version == '1.57.0'
+        if: matrix.rust.version == '1.63.0'
         run: |
-          cargo update -p log --precise "0.4.18"
-          cargo update -p tempfile --precise "3.6.0"
-          cargo update -p reqwest --precise "0.11.18"
-          cargo update -p hyper-rustls --precise 0.24.0
-          cargo update -p rustls:0.21.9 --precise "0.21.1"
-          cargo update -p rustls:0.20.9 --precise "0.20.8"
-          cargo update -p tokio --precise "1.29.1"
-          cargo update -p tokio-util --precise "0.7.8"
-          cargo update -p flate2 --precise "1.0.26"
-          cargo update -p h2 --precise "0.3.20"
-          cargo update -p rustls-webpki:0.100.3 --precise "0.100.1"
-          cargo update -p rustls-webpki:0.101.7 --precise "0.101.1"
-          cargo update -p zip --precise "0.6.2"
-          cargo update -p time --precise "0.3.13"
-          cargo update -p byteorder --precise "1.4.3"
-          cargo update -p webpki --precise "0.22.2"
-          cargo update -p os_str_bytes --precise 6.5.1
-          cargo update -p sct --precise 0.7.0
-          cargo update -p cc --precise "1.0.81"
-          cargo update -p jobserver --precise "0.1.26"
+          cargo update -p zstd-sys --precise "2.0.8+zstd.1.5.5"
+          cargo update -p time --precise "0.3.20"
+          cargo update -p home --precise "0.5.5"
+          cargo update -p proptest --precise "1.2.0"
       - name: Build
         run: cargo build ${{ matrix.features }}
       - name: Test
@@ -134,9 +118,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions-rs/toolchain@v1
         with:
-            # we pin clippy instead of using "stable" so that our CI doesn't break
-            # at each new cargo release
-            toolchain: "1.67.0"
+            toolchain: 1.78.0
             components: clippy
             override: true
       - name: Rust Cache

.github/workflows/nightly_docs.yml

@@ -17,6 +17,8 @@ jobs:
         run: rustup update
       - name: Rust Cache
         uses: Swatinem/rust-cache@v2.2.1
+      - name: Pin dependencies for MSRV
+        run: cargo update -p home --precise "0.5.5"
       - name: Build docs
         run: cargo doc --no-deps
         env:

Cargo.toml

@@ -7,6 +7,9 @@ members = [
     "crates/electrum",
     "crates/esplora",
     "crates/bitcoind_rpc",
+    "crates/hwi",
+    "crates/persist",
+    "crates/testenv",
     "example-crates/example_cli",
     "example-crates/example_electrum",
     "example-crates/example_esplora",
@@ -14,6 +17,7 @@ members = [
     "example-crates/wallet_electrum",
     "example-crates/wallet_esplora_blocking",
     "example-crates/wallet_esplora_async",
+    "example-crates/wallet_rpc",
     "nursery/tmp_plan",
     "nursery/coin_select"
 ]

README.md

@@ -15,7 +15,7 @@
     <a href="https://github.com/bitcoindevkit/bdk/actions?query=workflow%3ACI"><img alt="CI Status" src="https://github.com/bitcoindevkit/bdk/workflows/CI/badge.svg"></a>
     <a href="https://coveralls.io/github/bitcoindevkit/bdk?branch=master"><img src="https://coveralls.io/repos/github/bitcoindevkit/bdk/badge.svg?branch=master"/></a>
     <a href="https://docs.rs/bdk"><img alt="API Docs" src="https://img.shields.io/badge/docs.rs-bdk-green"/></a>
-    <a href="https://blog.rust-lang.org/2021/12/02/Rust-1.57.0.html"><img alt="Rustc Version 1.57.0+" src="https://img.shields.io/badge/rustc-1.57.0%2B-lightgrey.svg"/></a>
+    <a href="https://blog.rust-lang.org/2022/08/11/Rust-1.63.0.html"><img alt="Rustc Version 1.63.0+" src="https://img.shields.io/badge/rustc-1.63.0%2B-lightgrey.svg"/></a>
     <a href="https://discord.gg/d7NkDKm"><img alt="Chat on Discord" src="https://img.shields.io/discord/753336465005608961?logo=discord"></a>
   </p>
 
@@ -41,6 +41,7 @@ The project is split up into several crates in the `/crates` directory:
 
 - [`bdk`](./crates/bdk): Contains the central high level `Wallet` type that is built from the low-level mechanisms provided by the other components
 - [`chain`](./crates/chain): Tools for storing and indexing chain data
+- [`persist`](./crates/persist): Types that define data persistence of a BDK wallet
 - [`file_store`](./crates/file_store): A (experimental) persistence backend for storing chain data in a single file.
 - [`esplora`](./crates/esplora): Extends the [`esplora-client`] crate with methods to fetch chain data from an esplora HTTP server in the form that [`bdk_chain`] and `Wallet` can consume.
 - [`electrum`](./crates/electrum): Extends the [`electrum-client`] crate with methods to fetch chain data from an electrum server in the form that [`bdk_chain`] and `Wallet` can consume.
@@ -48,6 +49,8 @@ The project is split up into several crates in the `/crates` directory:
 Fully working examples of how to use these components are in `/example-crates`:
 - [`example_cli`](./example-crates/example_cli): Library used by the `example_*` crates. Provides utilities for syncing, showing the balance, generating addresses and creating transactions without using the bdk `Wallet`.
 - [`example_electrum`](./example-crates/example_electrum): A command line Bitcoin wallet application built on top of `example_cli` and the `electrum` crate. It shows the power of the bdk tools (`chain` + `file_store` + `electrum`), without depending on the main `bdk` library.
+- [`example_esplora`](./example-crates/example_esplora): A command line Bitcoin wallet application built on top of `example_cli` and the `esplora` crate. It shows the power of the bdk tools (`chain` + `file_store` + `esplora`), without depending on the main `bdk` library.
+- [`example_bitcoind_rpc_polling`](./example-crates/example_bitcoind_rpc_polling): A command line Bitcoin wallet application built on top of `example_cli` and the `bitcoind_rpc` crate. It shows the power of the bdk tools (`chain` + `file_store` + `bitcoind_rpc`), without depending on the main `bdk` library.
 - [`wallet_esplora_blocking`](./example-crates/wallet_esplora_blocking): Uses the `Wallet` to sync and spend using the Esplora blocking interface.
 - [`wallet_esplora_async`](./example-crates/wallet_esplora_async): Uses the `Wallet` to sync and spend using the Esplora asynchronous interface.
 - [`wallet_electrum`](./example-crates/wallet_electrum): Uses the `Wallet` to sync and spend using Electrum.
@@ -60,51 +63,21 @@ Fully working examples of how to use these components are in `/example-crates`:
 [`bdk_chain`]: https://docs.rs/bdk-chain/
 
 ## Minimum Supported Rust Version (MSRV)
-This library should compile with any combination of features with Rust 1.57.0.
+This library should compile with any combination of features with Rust 1.63.0.
 
 To build with the MSRV you will need to pin dependencies as follows:
 
 ```shell
-# log 0.4.19 has MSRV 1.60.0+
-cargo update -p log --precise "0.4.18"
-# tempfile 3.7.0 has MSRV 1.63.0+
-cargo update -p tempfile --precise "3.6.0"
-# reqwest 0.11.19 has MSRV 1.63.0+
-cargo update -p reqwest --precise "0.11.18"
-# hyper-rustls 0.24.1 has MSRV 1.60.0+
-cargo update -p hyper-rustls --precise 0.24.0
-# rustls 0.21.7 has MSRV 1.60.0+
-cargo update -p rustls:0.21.9 --precise "0.21.1"
-# rustls 0.20.9 has MSRV 1.60.0+
-cargo update -p rustls:0.20.9 --precise "0.20.8"
-# tokio 1.33 has MSRV 1.63.0+
-cargo update -p tokio --precise "1.29.1"
-# tokio-util 0.7.9 doesn't build with MSRV 1.57.0
-cargo update -p tokio-util --precise "0.7.8"
-# flate2 1.0.27 has MSRV 1.63.0+
-cargo update -p flate2 --precise "1.0.26"
-# h2 0.3.21 has MSRV 1.63.0+
-cargo update -p h2 --precise "0.3.20"
-# rustls-webpki 0.100.3 has MSRV 1.60.0+
-cargo update -p rustls-webpki:0.100.3 --precise "0.100.1"
-# rustls-webpki 0.101.2 has MSRV 1.60.0+
-cargo update -p rustls-webpki:0.101.7 --precise "0.101.1"
-# zip 0.6.6 has MSRV 1.59.0+
+# zip 0.6.3 has MSRV 1.64.0
 cargo update -p zip --precise "0.6.2"
-# time 0.3.14 has MSRV 1.59.0+
-cargo update -p time --precise "0.3.13"
-# byteorder 1.5.0 has MSRV 1.60.0+
-cargo update -p byteorder --precise "1.4.3"
-# webpki 0.22.4 requires `ring:0.17.2` which has MSRV 1.61.0+
-cargo update -p webpki --precise "0.22.2"
-# os_str_bytes 6.6.0 has MSRV 1.61.0+
-cargo update -p os_str_bytes --precise 6.5.1
-# sct 0.7.1 has MSRV 1.61.0+
-cargo update -p sct --precise 0.7.0
-# cc 1.0.82 has MSRV 1.61.0+
-cargo update -p cc --precise "1.0.81"
-# jobserver 0.1.27 has MSRV 1.66.0+
+# time 0.3.21 has MSRV 1.65.0
+cargo update -p time --precise "0.3.20"
+# jobserver 0.1.27 has MSRV 1.66.0
 cargo update -p jobserver --precise "0.1.26"
+# home 0.5.9 has MSRV 1.70.0
+cargo update -p home --precise "0.5.5"
+# proptest 1.4.0 has MSRV 1.65.0
+cargo update -p proptest --precise "1.2.0"
 ```
 
 ## License

clippy.toml

@@ -1 +1 @@
-msrv="1.57.0"
+msrv="1.63.0"

crates/bdk/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "bdk"
 homepage = "https://bitcoindevkit.org"
-version = "1.0.0-alpha.2"
+version = "1.0.0-alpha.11"
 repository = "https://github.com/bitcoindevkit/bdk"
 documentation = "https://docs.rs/bdk"
 description = "A modern, lightweight, descriptor-based wallet library"
@@ -10,19 +10,20 @@ readme = "README.md"
 license = "MIT OR Apache-2.0"
 authors = ["Bitcoin Dev Kit Developers"]
 edition = "2021"
-rust-version = "1.57"
+rust-version = "1.63"
 
 [dependencies]
+anyhow = { version = "1", default-features = false }
 rand = "^0.8"
-miniscript = { version = "10.0.0", features = ["serde"], default-features = false }
-bitcoin = { version = "0.30.0", features = ["serde", "base64", "rand-std"], default-features = false }
+miniscript = { version = "11.0.0", features = ["serde"], default-features = false }
+bitcoin = { version = "0.31.0", features = ["serde", "base64", "rand-std"], default-features = false }
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = { version = "^1.0" }
-bdk_chain = { path = "../chain", version = "0.6.0", features = ["miniscript", "serde"], default-features = false }
+bdk_chain = { path = "../chain", version = "0.14.0", features = ["miniscript", "serde"], default-features = false }
+bdk_persist = { path = "../persist", version = "0.2.0" }
 
 # Optional dependencies
-hwi = { version = "0.7.0", optional = true, features = [ "miniscript"] }
-bip39 = { version = "1.0.1", optional = true }
+bip39 = { version = "2.0", optional = true }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 getrandom = "0.2"
@@ -34,8 +35,6 @@ std = ["bitcoin/std", "miniscript/std", "bdk_chain/std"]
 compiler = ["miniscript/compiler"]
 all-keys = ["keys-bip39"]
 keys-bip39 = ["bip39"]
-hardware-signer = ["hwi"]
-test-hardware-signer = ["hardware-signer"]
 
 # This feature is used to run `cargo check` in our CI targeting wasm. It's not recommended
 # for libraries to explicitly include the "getrandom/js" feature, so we only do it when

crates/bdk/README.md

@@ -13,7 +13,7 @@
     <a href="https://github.com/bitcoindevkit/bdk/actions?query=workflow%3ACI"><img alt="CI Status" src="https://github.com/bitcoindevkit/bdk/workflows/CI/badge.svg"></a>
     <a href="https://coveralls.io/github/bitcoindevkit/bdk?branch=master"><img src="https://coveralls.io/repos/github/bitcoindevkit/bdk/badge.svg?branch=master"/></a>
     <a href="https://docs.rs/bdk"><img alt="API Docs" src="https://img.shields.io/badge/docs.rs-bdk-green"/></a>
-    <a href="https://blog.rust-lang.org/2021/12/02/Rust-1.57.0.html"><img alt="Rustc Version 1.57.0+" src="https://img.shields.io/badge/rustc-1.57.0%2B-lightgrey.svg"/></a>
+    <a href="https://blog.rust-lang.org/2022/08/11/Rust-1.63.0.html"><img alt="Rustc Version 1.63.0+" src="https://img.shields.io/badge/rustc-1.63.0%2B-lightgrey.svg"/></a>
     <a href="https://discord.gg/d7NkDKm"><img alt="Chat on Discord" src="https://img.shields.io/discord/753336465005608961?logo=discord"></a>
   </p>
 
@@ -26,7 +26,7 @@
 
 ## `bdk`
 
-The `bdk` crate provides the [`Wallet`](`crate::Wallet`) type which is a simple, high-level
+The `bdk` crate provides the [`Wallet`] type which is a simple, high-level
 interface built from the low-level components of [`bdk_chain`]. `Wallet` is a good starting point
 for many simple applications as well as a good demonstration of how to use the other mechanisms to
 construct a wallet. It has two keychains (external and internal) which are defined by
@@ -34,51 +34,51 @@ construct a wallet. It has two keychains (external and internal) which are defin
 chain data it also uses the descriptors to find transaction outputs owned by them. From there, you
 can create and sign transactions.
 
-For more information, see the [`Wallet`'s documentation](https://docs.rs/bdk/latest/bdk/wallet/struct.Wallet.html).
+For details about the API of `Wallet` see the [module-level documentation][`Wallet`].
 
 ### Blockchain data
 
-In order to get blockchain data for `Wallet` to consume, you have to put it into particular form.
-Right now this is [`KeychainScan`] which is defined in [`bdk_chain`].
-
-This can be created manually or from blockchain-scanning crates.
+In order to get blockchain data for `Wallet` to consume, you should configure a client from
+an available chain source. Typically you make a request to the chain source and get a response
+that the `Wallet` can use to update its view of the chain.
 
 **Blockchain Data Sources**
 
 * [`bdk_esplora`]: Grabs blockchain data from Esplora for updating BDK structures.
 * [`bdk_electrum`]: Grabs blockchain data from Electrum for updating BDK structures.
+* [`bdk_bitcoind_rpc`]: Grabs blockchain data from Bitcoin Core for updating BDK structures.
 
 **Examples**
 
-* [`example-crates/wallet_esplora`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_esplora)
+* [`example-crates/wallet_esplora_async`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_esplora_async)
+* [`example-crates/wallet_esplora_blocking`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_esplora_blocking)
 * [`example-crates/wallet_electrum`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_electrum)
+* [`example-crates/wallet_rpc`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_rpc)
 
 ### Persistence
 
-To persist the `Wallet` on disk, `Wallet` needs to be constructed with a
-[`Persist`](https://docs.rs/bdk_chain/latest/bdk_chain/keychain/struct.KeychainPersist.html) implementation.
+To persist the `Wallet` on disk, it must be constructed with a [`PersistBackend`] implementation.
 
 **Implementations**
 
-* [`bdk_file_store`]: a simple flat-file implementation of `Persist`.
+* [`bdk_file_store`]: A simple flat-file implementation of [`PersistBackend`].
 
 **Example**
 
-```rust
-use bdk::{bitcoin::Network, wallet::{AddressIndex, Wallet}};
+<!-- compile_fail because outpoint and txout are fake variables -->
+```rust,compile_fail
+use bdk::{bitcoin::Network, wallet::{ChangeSet, Wallet}};
 
 fn main() {
-    // a type that implements `Persist`
-    let db = ();
+    // Create a new file `Store`.
+    let db = bdk_file_store::Store::<ChangeSet>::open_or_create_new(b"magic_bytes", "path/to/my_wallet.db").expect("create store");
 
-    let descriptor = "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/0'/0'/0/*)";
-    let mut wallet = Wallet::new(descriptor, None, db, Network::Testnet).expect("should create");
+    let descriptor = "wpkh(tprv8ZgxMBicQKsPdcAqYBpzAFwU5yxBUo88ggoBqu1qPcHUfSbKK1sKMLmC7EAk438btHQrSdu3jGGQa6PA71nvH5nkDexhLteJqkM4dQmWF9g/84'/1'/0'/0/*)";
+    let mut wallet = Wallet::new_or_load(descriptor, None, db, Network::Testnet).expect("create or load wallet");
 
-    // get a new address (this increments revealed derivation index)
-    println!("revealed address: {}", wallet.get_address(AddressIndex::New));
-    println!("staged changes: {:?}", wallet.staged());
-    // persist changes
-    wallet.commit().expect("must save");
+    // Insert a single `TxOut` at `OutPoint` into the wallet.
+    let _ = wallet.insert_txout(outpoint, txout);
+    wallet.commit().expect("must write to database");
 }
 ```
 
@@ -218,9 +218,11 @@ submitted for inclusion in the work by you, as defined in the Apache-2.0
 license, shall be dual licensed as above, without any additional terms or
 conditions.
 
+[`Wallet`]: https://docs.rs/bdk/1.0.0-alpha.7/bdk/wallet/struct.Wallet.html
+[`PersistBackend`]: https://docs.rs/bdk_persist/latest/bdk_persist/trait.PersistBackend.html
 [`bdk_chain`]: https://docs.rs/bdk_chain/latest
 [`bdk_file_store`]: https://docs.rs/bdk_file_store/latest
 [`bdk_electrum`]: https://docs.rs/bdk_electrum/latest
 [`bdk_esplora`]: https://docs.rs/bdk_esplora/latest
-[`KeychainScan`]: https://docs.rs/bdk_chain/latest/bdk_chain/keychain/struct.KeychainScan.html
+[`bdk_bitcoind_rpc`]: https://docs.rs/bdk_bitcoind_rpc/latest
 [`rust-miniscript`]: https://docs.rs/miniscript/latest/miniscript/index.html

crates/bdk/examples/compiler.rs

@@ -21,7 +21,6 @@ use bitcoin::Network;
 use miniscript::policy::Concrete;
 use miniscript::Descriptor;
 
-use bdk::wallet::AddressIndex::New;
 use bdk::{KeychainKind, Wallet};
 
 /// Miniscript policy is a high level abstraction of spending conditions. Defined in the
@@ -51,7 +50,7 @@ fn main() -> Result<(), Box<dyn Error>> {
 
     println!(
         "First derived address from the descriptor: \n{}",
-        wallet.get_address(New)
+        wallet.next_unused_address(KeychainKind::External)?,
     );
 
     // BDK also has it's own `Policy` structure to represent the spending condition in a more

crates/bdk/examples/mnemonic_to_descriptors.rs

@@ -33,8 +33,8 @@ fn main() -> Result<(), anyhow::Error> {
     let mnemonic_with_passphrase = (mnemonic, None);
 
     // define external and internal derivation key path
-    let external_path = DerivationPath::from_str("m/86h/0h/0h/0").unwrap();
-    let internal_path = DerivationPath::from_str("m/86h/0h/0h/1").unwrap();
+    let external_path = DerivationPath::from_str("m/86h/1h/0h/0").unwrap();
+    let internal_path = DerivationPath::from_str("m/86h/1h/0h/1").unwrap();
 
     // generate external and internal descriptor from mnemonic
     let (external_descriptor, ext_keymap) =

crates/bdk/src/descriptor/checksum.rs

@@ -42,22 +42,16 @@ fn poly_mod(mut c: u64, val: u64) -> u64 {
     c
 }
 
-/// Computes the checksum bytes of a descriptor.
-/// `exclude_hash = true` ignores all data after the first '#' (inclusive).
-pub(crate) fn calc_checksum_bytes_internal(
-    mut desc: &str,
-    exclude_hash: bool,
-) -> Result<[u8; 8], DescriptorError> {
+/// Compute the checksum bytes of a descriptor, excludes any existing checksum in the descriptor string from the calculation
+pub fn calc_checksum_bytes(mut desc: &str) -> Result<[u8; 8], DescriptorError> {
     let mut c = 1;
     let mut cls = 0;
     let mut clscount = 0;
 
     let mut original_checksum = None;
-    if exclude_hash {
-        if let Some(split) = desc.split_once('#') {
-            desc = split.0;
-            original_checksum = Some(split.1);
-        }
+    if let Some(split) = desc.split_once('#') {
+        desc = split.0;
+        original_checksum = Some(split.1);
     }
 
     for ch in desc.as_bytes() {
@@ -95,39 +89,10 @@ pub(crate) fn calc_checksum_bytes_internal(
     Ok(checksum)
 }
 
-/// Compute the checksum bytes of a descriptor, excludes any existing checksum in the descriptor string from the calculation
-pub fn calc_checksum_bytes(desc: &str) -> Result<[u8; 8], DescriptorError> {
-    calc_checksum_bytes_internal(desc, true)
-}
-
 /// Compute the checksum of a descriptor, excludes any existing checksum in the descriptor string from the calculation
 pub fn calc_checksum(desc: &str) -> Result<String, DescriptorError> {
     // unsafe is okay here as the checksum only uses bytes in `CHECKSUM_CHARSET`
-    calc_checksum_bytes_internal(desc, true)
-        .map(|b| unsafe { String::from_utf8_unchecked(b.to_vec()) })
-}
-
-// TODO in release 0.25.0, remove get_checksum_bytes and get_checksum
-// TODO in release 0.25.0, consolidate calc_checksum_bytes_internal into calc_checksum_bytes
-
-/// Compute the checksum bytes of a descriptor
-#[deprecated(
-    since = "0.24.0",
-    note = "Use new `calc_checksum_bytes` function which excludes any existing checksum in the descriptor string before calculating the checksum hash bytes. See https://github.com/bitcoindevkit/bdk/pull/765."
-)]
-pub fn get_checksum_bytes(desc: &str) -> Result<[u8; 8], DescriptorError> {
-    calc_checksum_bytes_internal(desc, false)
-}
-
-/// Compute the checksum of a descriptor
-#[deprecated(
-    since = "0.24.0",
-    note = "Use new `calc_checksum` function which excludes any existing checksum in the descriptor string before calculating the checksum hash. See https://github.com/bitcoindevkit/bdk/pull/765."
-)]
-pub fn get_checksum(desc: &str) -> Result<String, DescriptorError> {
-    // unsafe is okay here as the checksum only uses bytes in `CHECKSUM_CHARSET`
-    calc_checksum_bytes_internal(desc, false)
-        .map(|b| unsafe { String::from_utf8_unchecked(b.to_vec()) })
+    calc_checksum_bytes(desc).map(|b| unsafe { String::from_utf8_unchecked(b.to_vec()) })
 }
 
 #[cfg(test)]

crates/bdk/src/descriptor/dsl.rs

@@ -274,14 +274,13 @@ macro_rules! impl_sortedmulti {
 #[macro_export]
 macro_rules! parse_tap_tree {
     ( @merge $tree_a:expr, $tree_b:expr) => {{
-        use $crate::alloc::sync::Arc;
         use $crate::miniscript::descriptor::TapTree;
 
         $tree_a
             .and_then(|tree_a| Ok((tree_a, $tree_b?)))
             .and_then(|((a_tree, mut a_keymap, a_networks), (b_tree, b_keymap, b_networks))| {
                 a_keymap.extend(b_keymap.into_iter());
-                Ok((TapTree::Tree(Arc::new(a_tree), Arc::new(b_tree)), a_keymap, $crate::keys::merge_networks(&a_networks, &b_networks)))
+                Ok((TapTree::combine(a_tree, b_tree), a_keymap, $crate::keys::merge_networks(&a_networks, &b_networks)))
             })
 
     }};
@@ -806,7 +805,7 @@ mod test {
     use crate::descriptor::{DescriptorError, DescriptorMeta};
     use crate::keys::{DescriptorKey, IntoDescriptorKey, ValidNetworks};
     use bitcoin::bip32;
-    use bitcoin::network::constants::Network::{Bitcoin, Regtest, Signet, Testnet};
+    use bitcoin::Network::{Bitcoin, Regtest, Signet, Testnet};
     use bitcoin::PrivateKey;
 
     // test the descriptor!() macro
@@ -936,7 +935,7 @@ mod test {
 
     #[test]
     fn test_bip32_legacy_descriptors() {
-        let xprv = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let xprv = bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
 
         let path = bip32::DerivationPath::from_str("m/0").unwrap();
         let desc_key = (xprv, path.clone()).into_descriptor_key().unwrap();
@@ -981,7 +980,7 @@ mod test {
 
     #[test]
     fn test_bip32_segwitv0_descriptors() {
-        let xprv = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let xprv = bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
 
         let path = bip32::DerivationPath::from_str("m/0").unwrap();
         let desc_key = (xprv, path.clone()).into_descriptor_key().unwrap();
@@ -1038,10 +1037,10 @@ mod test {
 
     #[test]
     fn test_dsl_sortedmulti() {
-        let key_1 = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let key_1 = bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         let path_1 = bip32::DerivationPath::from_str("m/0").unwrap();
 
-        let key_2 = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPegBHHnq7YEgM815dG24M2Jk5RVqipgDxF1HJ1tsnT815X5Fd5FRfMVUs8NZs9XCb6y9an8hRPThnhfwfXJ36intaekySHGF").unwrap();
+        let key_2 = bip32::Xpriv::from_str("tprv8ZgxMBicQKsPegBHHnq7YEgM815dG24M2Jk5RVqipgDxF1HJ1tsnT815X5Fd5FRfMVUs8NZs9XCb6y9an8hRPThnhfwfXJ36intaekySHGF").unwrap();
         let path_2 = bip32::DerivationPath::from_str("m/1").unwrap();
 
         let desc_key1 = (key_1, path_1);
@@ -1097,7 +1096,7 @@ mod test {
     // - verify the valid_networks returned is correctly computed based on the keys present in the descriptor
     #[test]
     fn test_valid_networks() {
-        let xprv = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let xprv = bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         let path = bip32::DerivationPath::from_str("m/0").unwrap();
         let desc_key = (xprv, path).into_descriptor_key().unwrap();
 
@@ -1107,7 +1106,7 @@ mod test {
             [Testnet, Regtest, Signet].iter().cloned().collect()
         );
 
-        let xprv = bip32::ExtendedPrivKey::from_str("xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi").unwrap();
+        let xprv = bip32::Xpriv::from_str("xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi").unwrap();
         let path = bip32::DerivationPath::from_str("m/10/20/30/40").unwrap();
         let desc_key = (xprv, path).into_descriptor_key().unwrap();
 
@@ -1120,15 +1119,15 @@ mod test {
     fn test_key_maps_merged() {
         let secp = Secp256k1::new();
 
-        let xprv1 = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let xprv1 = bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         let path1 = bip32::DerivationPath::from_str("m/0").unwrap();
         let desc_key1 = (xprv1, path1.clone()).into_descriptor_key().unwrap();
 
-        let xprv2 = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPegBHHnq7YEgM815dG24M2Jk5RVqipgDxF1HJ1tsnT815X5Fd5FRfMVUs8NZs9XCb6y9an8hRPThnhfwfXJ36intaekySHGF").unwrap();
+        let xprv2 = bip32::Xpriv::from_str("tprv8ZgxMBicQKsPegBHHnq7YEgM815dG24M2Jk5RVqipgDxF1HJ1tsnT815X5Fd5FRfMVUs8NZs9XCb6y9an8hRPThnhfwfXJ36intaekySHGF").unwrap();
         let path2 = bip32::DerivationPath::from_str("m/2147483647'/0").unwrap();
         let desc_key2 = (xprv2, path2.clone()).into_descriptor_key().unwrap();
 
-        let xprv3 = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPdZXrcHNLf5JAJWFAoJ2TrstMRdSKtEggz6PddbuSkvHKM9oKJyFgZV1B7rw8oChspxyYbtmEXYyg1AjfWbL3ho3XHDpHRZf").unwrap();
+        let xprv3 = bip32::Xpriv::from_str("tprv8ZgxMBicQKsPdZXrcHNLf5JAJWFAoJ2TrstMRdSKtEggz6PddbuSkvHKM9oKJyFgZV1B7rw8oChspxyYbtmEXYyg1AjfWbL3ho3XHDpHRZf").unwrap();
         let path3 = bip32::DerivationPath::from_str("m/10/20/30/40").unwrap();
         let desc_key3 = (xprv3, path3.clone()).into_descriptor_key().unwrap();
 
@@ -1152,7 +1151,7 @@ mod test {
     #[test]
     fn test_script_context_validation() {
         // this compiles
-        let xprv = bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let xprv = bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         let path = bip32::DerivationPath::from_str("m/0").unwrap();
         let desc_key: DescriptorKey<Legacy> = (xprv, path).into_descriptor_key().unwrap();
 

crates/bdk/src/descriptor/error.rs

@@ -41,7 +41,7 @@ pub enum Error {
     /// Miniscript error
     Miniscript(miniscript::Error),
     /// Hex decoding error
-    Hex(bitcoin::hashes::hex::Error),
+    Hex(bitcoin::hex::HexToBytesError),
 }
 
 impl From<crate::keys::KeyError> for Error {
@@ -110,8 +110,8 @@ impl From<miniscript::Error> for Error {
     }
 }
 
-impl From<bitcoin::hashes::hex::Error> for Error {
-    fn from(err: bitcoin::hashes::hex::Error) -> Self {
+impl From<bitcoin::hex::HexToBytesError> for Error {
+    fn from(err: bitcoin::hex::HexToBytesError) -> Self {
         Error::Hex(err)
     }
 }

crates/bdk/src/descriptor/mod.rs

@@ -18,7 +18,7 @@ use crate::collections::BTreeMap;
 use alloc::string::String;
 use alloc::vec::Vec;
 
-use bitcoin::bip32::{ChildNumber, DerivationPath, ExtendedPubKey, Fingerprint, KeySource};
+use bitcoin::bip32::{ChildNumber, DerivationPath, Fingerprint, KeySource, Xpub};
 use bitcoin::{key::XOnlyPublicKey, secp256k1, PublicKey};
 use bitcoin::{psbt, taproot};
 use bitcoin::{Network, TxOut};
@@ -377,7 +377,7 @@ where
 pub(crate) trait DescriptorMeta {
     fn is_witness(&self) -> bool;
     fn is_taproot(&self) -> bool;
-    fn get_extended_keys(&self) -> Vec<DescriptorXKey<ExtendedPubKey>>;
+    fn get_extended_keys(&self) -> Vec<DescriptorXKey<Xpub>>;
     fn derive_from_hd_keypaths(
         &self,
         hd_keypaths: &HdKeyPaths,
@@ -418,7 +418,7 @@ impl DescriptorMeta for ExtendedDescriptor {
         self.desc_type() == DescriptorType::Tr
     }
 
-    fn get_extended_keys(&self) -> Vec<DescriptorXKey<ExtendedPubKey>> {
+    fn get_extended_keys(&self) -> Vec<DescriptorXKey<Xpub>> {
         let mut answer = Vec::new();
 
         self.for_each_key(|pk| {
@@ -438,21 +438,20 @@ impl DescriptorMeta for ExtendedDescriptor {
         secp: &SecpCtx,
     ) -> Option<DerivedDescriptor> {
         // Ensure that deriving `xpub` with `path` yields `expected`
-        let verify_key = |xpub: &DescriptorXKey<ExtendedPubKey>,
-                          path: &DerivationPath,
-                          expected: &SinglePubKey| {
-            let derived = xpub
-                .xkey
-                .derive_pub(secp, path)
-                .expect("The path should never contain hardened derivation steps")
-                .public_key;
+        let verify_key =
+            |xpub: &DescriptorXKey<Xpub>, path: &DerivationPath, expected: &SinglePubKey| {
+                let derived = xpub
+                    .xkey
+                    .derive_pub(secp, path)
+                    .expect("The path should never contain hardened derivation steps")
+                    .public_key;
 
-            match expected {
-                SinglePubKey::FullKey(pk) if &PublicKey::new(derived) == pk => true,
-                SinglePubKey::XOnly(pk) if &XOnlyPublicKey::from(derived) == pk => true,
-                _ => false,
-            }
-        };
+                match expected {
+                    SinglePubKey::FullKey(pk) if &PublicKey::new(derived) == pk => true,
+                    SinglePubKey::XOnly(pk) if &XOnlyPublicKey::from(derived) == pk => true,
+                    _ => false,
+                }
+            };
 
         let mut path_found = None;
 
@@ -605,10 +604,10 @@ mod test {
     use core::str::FromStr;
 
     use assert_matches::assert_matches;
-    use bitcoin::hashes::hex::FromHex;
+    use bitcoin::hex::FromHex;
     use bitcoin::secp256k1::Secp256k1;
     use bitcoin::ScriptBuf;
-    use bitcoin::{bip32, psbt::Psbt};
+    use bitcoin::{bip32, Psbt};
 
     use super::*;
     use crate::psbt::PsbtUtils;
@@ -727,7 +726,7 @@ mod test {
 
         let secp = Secp256k1::new();
 
-        let xprv = bip32::ExtendedPrivKey::from_str("xprv9s21ZrQH143K3c3gF1DUWpWNr2SG2XrG8oYPpqYh7hoWsJy9NjabErnzriJPpnGHyKz5NgdXmq1KVbqS1r4NXdCoKitWg5e86zqXHa8kxyB").unwrap();
+        let xprv = bip32::Xpriv::from_str("xprv9s21ZrQH143K3c3gF1DUWpWNr2SG2XrG8oYPpqYh7hoWsJy9NjabErnzriJPpnGHyKz5NgdXmq1KVbqS1r4NXdCoKitWg5e86zqXHa8kxyB").unwrap();
         let path = bip32::DerivationPath::from_str("m/0").unwrap();
 
         // here `to_descriptor_key` will set the valid networks for the key to only mainnet, since
@@ -746,7 +745,7 @@ mod test {
         let mut xprv_testnet = xprv;
         xprv_testnet.network = Network::Testnet;
 
-        let xpub_testnet = bip32::ExtendedPubKey::from_priv(&secp, &xprv_testnet);
+        let xpub_testnet = bip32::Xpub::from_priv(&secp, &xprv_testnet);
         let desc_pubkey = DescriptorPublicKey::XPub(DescriptorXKey {
             xkey: xpub_testnet,
             origin: None,
@@ -836,7 +835,7 @@ mod test {
     fn test_descriptor_from_str_from_output_of_macro() {
         let secp = Secp256k1::new();
 
-        let tpub = bip32::ExtendedPubKey::from_str("tpubD6NzVbkrYhZ4XHndKkuB8FifXm8r5FQHwrN6oZuWCz13qb93rtgKvD4PQsqC4HP4yhV3tA2fqr2RbY5mNXfM7RxXUoeABoDtsFUq2zJq6YK").unwrap();
+        let tpub = bip32::Xpub::from_str("tpubD6NzVbkrYhZ4XHndKkuB8FifXm8r5FQHwrN6oZuWCz13qb93rtgKvD4PQsqC4HP4yhV3tA2fqr2RbY5mNXfM7RxXUoeABoDtsFUq2zJq6YK").unwrap();
         let path = bip32::DerivationPath::from_str("m/1/2").unwrap();
         let key = (tpub, path).into_descriptor_key().unwrap();
 
@@ -895,7 +894,7 @@ mod test {
             .update_with_descriptor_unchecked(&descriptor)
             .unwrap();
 
-        assert_eq!(psbt_input.redeem_script, Some(script.to_v0_p2wsh()));
+        assert_eq!(psbt_input.redeem_script, Some(script.to_p2wsh()));
         assert_eq!(psbt_input.witness_script, Some(script));
     }
 }

crates/bdk/src/descriptor/policy.rs

@@ -1137,7 +1137,7 @@ impl ExtractPolicy for Descriptor<DescriptorPublicKey> {
                 let key_spend_sig =
                     miniscript::Tap::make_signature(tr.internal_key(), signers, build_sat, secp);
 
-                if tr.taptree().is_none() {
+                if tr.tap_tree().is_none() {
                     Ok(Some(key_spend_sig))
                 } else {
                     let mut items = vec![key_spend_sig];
@@ -1184,8 +1184,8 @@ mod test {
         secp: &SecpCtx,
     ) -> (DescriptorKey<Ctx>, DescriptorKey<Ctx>, Fingerprint) {
         let path = bip32::DerivationPath::from_str(path).unwrap();
-        let tprv = bip32::ExtendedPrivKey::from_str(tprv).unwrap();
-        let tpub = bip32::ExtendedPubKey::from_priv(secp, &tprv);
+        let tprv = bip32::Xpriv::from_str(tprv).unwrap();
+        let tpub = bip32::Xpub::from_priv(secp, &tprv);
         let fingerprint = tprv.fingerprint(secp);
         let prvkey = (tprv, path.clone()).into_descriptor_key().unwrap();
         let pubkey = (tpub, path).into_descriptor_key().unwrap();

crates/bdk/src/descriptor/template.rs

@@ -74,7 +74,7 @@ impl<T: DescriptorTemplate> IntoWalletDescriptor for T {
 /// ```
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::Wallet;
-/// # use bdk::wallet::AddressIndex::New;
+/// # use bdk::KeychainKind;
 /// use bdk::template::P2Pkh;
 ///
 /// let key =
@@ -82,7 +82,9 @@ impl<T: DescriptorTemplate> IntoWalletDescriptor for T {
 /// let mut wallet = Wallet::new_no_persist(P2Pkh(key), None, Network::Testnet)?;
 ///
 /// assert_eq!(
-///     wallet.get_address(New).to_string(),
+///     wallet
+///         .next_unused_address(KeychainKind::External)?
+///         .to_string(),
 ///     "mwJ8hxFYW19JLuc65RCTaP4v1rzVU8cVMT"
 /// );
 /// # Ok::<_, Box<dyn std::error::Error>>(())
@@ -102,15 +104,17 @@ impl<K: IntoDescriptorKey<Legacy>> DescriptorTemplate for P2Pkh<K> {
 /// ```
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::Wallet;
+/// # use bdk::KeychainKind;
 /// use bdk::template::P2Wpkh_P2Sh;
-/// use bdk::wallet::AddressIndex;
 ///
 /// let key =
 ///     bitcoin::PrivateKey::from_wif("cTc4vURSzdx6QE6KVynWGomDbLaA75dNALMNyfjh3p8DRRar84Um")?;
 /// let mut wallet = Wallet::new_no_persist(P2Wpkh_P2Sh(key), None, Network::Testnet)?;
 ///
 /// assert_eq!(
-///     wallet.get_address(AddressIndex::New).to_string(),
+///     wallet
+///         .next_unused_address(KeychainKind::External)?
+///         .to_string(),
 ///     "2NB4ox5VDRw1ecUv6SnT3VQHPXveYztRqk5"
 /// );
 /// # Ok::<_, Box<dyn std::error::Error>>(())
@@ -131,15 +135,17 @@ impl<K: IntoDescriptorKey<Segwitv0>> DescriptorTemplate for P2Wpkh_P2Sh<K> {
 /// ```
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::{Wallet};
+/// # use bdk::KeychainKind;
 /// use bdk::template::P2Wpkh;
-/// use bdk::wallet::AddressIndex::New;
 ///
 /// let key =
 ///     bitcoin::PrivateKey::from_wif("cTc4vURSzdx6QE6KVynWGomDbLaA75dNALMNyfjh3p8DRRar84Um")?;
 /// let mut wallet = Wallet::new_no_persist(P2Wpkh(key), None, Network::Testnet)?;
 ///
 /// assert_eq!(
-///     wallet.get_address(New).to_string(),
+///     wallet
+///         .next_unused_address(KeychainKind::External)?
+///         .to_string(),
 ///     "tb1q4525hmgw265tl3drrl8jjta7ayffu6jf68ltjd"
 /// );
 /// # Ok::<_, Box<dyn std::error::Error>>(())
@@ -159,7 +165,7 @@ impl<K: IntoDescriptorKey<Segwitv0>> DescriptorTemplate for P2Wpkh<K> {
 /// ```
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::Wallet;
-/// # use bdk::wallet::AddressIndex::New;
+/// # use bdk::KeychainKind;
 /// use bdk::template::P2TR;
 ///
 /// let key =
@@ -167,7 +173,9 @@ impl<K: IntoDescriptorKey<Segwitv0>> DescriptorTemplate for P2Wpkh<K> {
 /// let mut wallet = Wallet::new_no_persist(P2TR(key), None, Network::Testnet)?;
 ///
 /// assert_eq!(
-///     wallet.get_address(New).to_string(),
+///     wallet
+///         .next_unused_address(KeychainKind::External)?
+///         .to_string(),
 ///     "tb1pvjf9t34fznr53u5tqhejz4nr69luzkhlvsdsdfq9pglutrpve2xq7hps46"
 /// );
 /// # Ok::<_, Box<dyn std::error::Error>>(())
@@ -192,17 +200,16 @@ impl<K: IntoDescriptorKey<Tap>> DescriptorTemplate for P2TR<K> {
 /// # use std::str::FromStr;
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
 /// use bdk::template::Bip44;
 ///
-/// let key = bitcoin::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPeZRHk4rTG6orPS2CRNFX3njhUXx5vj9qGog5ZMH4uGReDWN5kCkY3jmWEtWause41CDvBRXD1shKknAMKxT99o9qUTRVC6m")?;
+/// let key = bitcoin::bip32::Xpriv::from_str("tprv8ZgxMBicQKsPeZRHk4rTG6orPS2CRNFX3njhUXx5vj9qGog5ZMH4uGReDWN5kCkY3jmWEtWause41CDvBRXD1shKknAMKxT99o9qUTRVC6m")?;
 /// let mut wallet = Wallet::new_no_persist(
 ///     Bip44(key.clone(), KeychainKind::External),
 ///     Some(Bip44(key, KeychainKind::Internal)),
 ///     Network::Testnet,
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New).to_string(), "mmogjc7HJEZkrLqyQYqJmxUqFaC7i4uf89");
+/// assert_eq!(wallet.next_unused_address(KeychainKind::External)?.to_string(), "mmogjc7HJEZkrLqyQYqJmxUqFaC7i4uf89");
 /// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "pkh([c55b303f/44'/1'/0']tpubDCuorCpzvYS2LCD75BR46KHE8GdDeg1wsAgNZeNr6DaB5gQK1o14uErKwKLuFmeemkQ6N2m3rNgvctdJLyr7nwu2yia7413Hhg8WWE44cgT/0/*)#5wrnv0xt");
 /// # Ok::<_, Box<dyn std::error::Error>>(())
 /// ```
@@ -229,10 +236,9 @@ impl<K: DerivableKey<Legacy>> DescriptorTemplate for Bip44<K> {
 /// # use std::str::FromStr;
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
 /// use bdk::template::Bip44Public;
 ///
-/// let key = bitcoin::bip32::ExtendedPubKey::from_str("tpubDDDzQ31JkZB7VxUr9bjvBivDdqoFLrDPyLWtLapArAi51ftfmCb2DPxwLQzX65iNcXz1DGaVvyvo6JQ6rTU73r2gqdEo8uov9QKRb7nKCSU")?;
+/// let key = bitcoin::bip32::Xpub::from_str("tpubDDDzQ31JkZB7VxUr9bjvBivDdqoFLrDPyLWtLapArAi51ftfmCb2DPxwLQzX65iNcXz1DGaVvyvo6JQ6rTU73r2gqdEo8uov9QKRb7nKCSU")?;
 /// let fingerprint = bitcoin::bip32::Fingerprint::from_str("c55b303f")?;
 /// let mut wallet = Wallet::new_no_persist(
 ///     Bip44Public(key.clone(), fingerprint, KeychainKind::External),
@@ -240,7 +246,7 @@ impl<K: DerivableKey<Legacy>> DescriptorTemplate for Bip44<K> {
 ///     Network::Testnet,
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New).to_string(), "miNG7dJTzJqNbFS19svRdTCisC65dsubtR");
+/// assert_eq!(wallet.next_unused_address(KeychainKind::External)?.to_string(), "miNG7dJTzJqNbFS19svRdTCisC65dsubtR");
 /// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "pkh([c55b303f/44'/1'/0']tpubDDDzQ31JkZB7VxUr9bjvBivDdqoFLrDPyLWtLapArAi51ftfmCb2DPxwLQzX65iNcXz1DGaVvyvo6JQ6rTU73r2gqdEo8uov9QKRb7nKCSU/0/*)#cfhumdqz");
 /// # Ok::<_, Box<dyn std::error::Error>>(())
 /// ```
@@ -267,17 +273,16 @@ impl<K: DerivableKey<Legacy>> DescriptorTemplate for Bip44Public<K> {
 /// # use std::str::FromStr;
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
 /// use bdk::template::Bip49;
 ///
-/// let key = bitcoin::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPeZRHk4rTG6orPS2CRNFX3njhUXx5vj9qGog5ZMH4uGReDWN5kCkY3jmWEtWause41CDvBRXD1shKknAMKxT99o9qUTRVC6m")?;
+/// let key = bitcoin::bip32::Xpriv::from_str("tprv8ZgxMBicQKsPeZRHk4rTG6orPS2CRNFX3njhUXx5vj9qGog5ZMH4uGReDWN5kCkY3jmWEtWause41CDvBRXD1shKknAMKxT99o9qUTRVC6m")?;
 /// let mut wallet = Wallet::new_no_persist(
 ///     Bip49(key.clone(), KeychainKind::External),
 ///     Some(Bip49(key, KeychainKind::Internal)),
 ///     Network::Testnet,
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New).to_string(), "2N4zkWAoGdUv4NXhSsU8DvS5MB36T8nKHEB");
+/// assert_eq!(wallet.next_unused_address(KeychainKind::External)?.to_string(), "2N4zkWAoGdUv4NXhSsU8DvS5MB36T8nKHEB");
 /// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "sh(wpkh([c55b303f/49'/1'/0']tpubDDYr4kdnZgjjShzYNjZUZXUUtpXaofdkMaipyS8ThEh45qFmhT4hKYways7UXmg6V7het1QiFo9kf4kYUXyDvV4rHEyvSpys9pjCB3pukxi/0/*))#s9vxlc8e");
 /// # Ok::<_, Box<dyn std::error::Error>>(())
 /// ```
@@ -304,10 +309,9 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip49<K> {
 /// # use std::str::FromStr;
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
 /// use bdk::template::Bip49Public;
 ///
-/// let key = bitcoin::bip32::ExtendedPubKey::from_str("tpubDC49r947KGK52X5rBWS4BLs5m9SRY3pYHnvRrm7HcybZ3BfdEsGFyzCMzayi1u58eT82ZeyFZwH7DD6Q83E3fM9CpfMtmnTygnLfP59jL9L")?;
+/// let key = bitcoin::bip32::Xpub::from_str("tpubDC49r947KGK52X5rBWS4BLs5m9SRY3pYHnvRrm7HcybZ3BfdEsGFyzCMzayi1u58eT82ZeyFZwH7DD6Q83E3fM9CpfMtmnTygnLfP59jL9L")?;
 /// let fingerprint = bitcoin::bip32::Fingerprint::from_str("c55b303f")?;
 /// let mut wallet = Wallet::new_no_persist(
 ///     Bip49Public(key.clone(), fingerprint, KeychainKind::External),
@@ -315,7 +319,7 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip49<K> {
 ///     Network::Testnet,
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New).to_string(), "2N3K4xbVAHoiTQSwxkZjWDfKoNC27pLkYnt");
+/// assert_eq!(wallet.next_unused_address(KeychainKind::External)?.to_string(), "2N3K4xbVAHoiTQSwxkZjWDfKoNC27pLkYnt");
 /// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "sh(wpkh([c55b303f/49'/1'/0']tpubDC49r947KGK52X5rBWS4BLs5m9SRY3pYHnvRrm7HcybZ3BfdEsGFyzCMzayi1u58eT82ZeyFZwH7DD6Q83E3fM9CpfMtmnTygnLfP59jL9L/0/*))#3tka9g0q");
 /// # Ok::<_, Box<dyn std::error::Error>>(())
 /// ```
@@ -342,17 +346,16 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip49Public<K> {
 /// # use std::str::FromStr;
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
 /// use bdk::template::Bip84;
 ///
-/// let key = bitcoin::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPeZRHk4rTG6orPS2CRNFX3njhUXx5vj9qGog5ZMH4uGReDWN5kCkY3jmWEtWause41CDvBRXD1shKknAMKxT99o9qUTRVC6m")?;
+/// let key = bitcoin::bip32::Xpriv::from_str("tprv8ZgxMBicQKsPeZRHk4rTG6orPS2CRNFX3njhUXx5vj9qGog5ZMH4uGReDWN5kCkY3jmWEtWause41CDvBRXD1shKknAMKxT99o9qUTRVC6m")?;
 /// let mut wallet = Wallet::new_no_persist(
 ///     Bip84(key.clone(), KeychainKind::External),
 ///     Some(Bip84(key, KeychainKind::Internal)),
 ///     Network::Testnet,
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New).to_string(), "tb1qhl85z42h7r4su5u37rvvw0gk8j2t3n9y7zsg4n");
+/// assert_eq!(wallet.next_unused_address(KeychainKind::External)?.to_string(), "tb1qhl85z42h7r4su5u37rvvw0gk8j2t3n9y7zsg4n");
 /// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "wpkh([c55b303f/84'/1'/0']tpubDDc5mum24DekpNw92t6fHGp8Gr2JjF9J7i4TZBtN6Vp8xpAULG5CFaKsfugWa5imhrQQUZKXe261asP5koDHo5bs3qNTmf3U3o4v9SaB8gg/0/*)#6kfecsmr");
 /// # Ok::<_, Box<dyn std::error::Error>>(())
 /// ```
@@ -379,10 +382,9 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip84<K> {
 /// # use std::str::FromStr;
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
 /// use bdk::template::Bip84Public;
 ///
-/// let key = bitcoin::bip32::ExtendedPubKey::from_str("tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q")?;
+/// let key = bitcoin::bip32::Xpub::from_str("tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q")?;
 /// let fingerprint = bitcoin::bip32::Fingerprint::from_str("c55b303f")?;
 /// let mut wallet = Wallet::new_no_persist(
 ///     Bip84Public(key.clone(), fingerprint, KeychainKind::External),
@@ -390,7 +392,7 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip84<K> {
 ///     Network::Testnet,
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New).to_string(), "tb1qedg9fdlf8cnnqfd5mks6uz5w4kgpk2pr6y4qc7");
+/// assert_eq!(wallet.next_unused_address(KeychainKind::External)?.to_string(), "tb1qedg9fdlf8cnnqfd5mks6uz5w4kgpk2pr6y4qc7");
 /// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "wpkh([c55b303f/84'/1'/0']tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q/0/*)#dhu402yv");
 /// # Ok::<_, Box<dyn std::error::Error>>(())
 /// ```
@@ -417,17 +419,16 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip84Public<K> {
 /// # use std::str::FromStr;
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
 /// use bdk::template::Bip86;
 ///
-/// let key = bitcoin::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPeZRHk4rTG6orPS2CRNFX3njhUXx5vj9qGog5ZMH4uGReDWN5kCkY3jmWEtWause41CDvBRXD1shKknAMKxT99o9qUTRVC6m")?;
+/// let key = bitcoin::bip32::Xpriv::from_str("tprv8ZgxMBicQKsPeZRHk4rTG6orPS2CRNFX3njhUXx5vj9qGog5ZMH4uGReDWN5kCkY3jmWEtWause41CDvBRXD1shKknAMKxT99o9qUTRVC6m")?;
 /// let mut wallet = Wallet::new_no_persist(
 ///     Bip86(key.clone(), KeychainKind::External),
 ///     Some(Bip86(key, KeychainKind::Internal)),
 ///     Network::Testnet,
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New).to_string(), "tb1p5unlj09djx8xsjwe97269kqtxqpwpu2epeskgqjfk4lnf69v4tnqpp35qu");
+/// assert_eq!(wallet.next_unused_address(KeychainKind::External)?.to_string(), "tb1p5unlj09djx8xsjwe97269kqtxqpwpu2epeskgqjfk4lnf69v4tnqpp35qu");
 /// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "tr([c55b303f/86'/1'/0']tpubDCiHofpEs47kx358bPdJmTZHmCDqQ8qw32upCSxHrSEdeeBs2T5Mq6QMB2ukeMqhNBiyhosBvJErteVhfURPGXPv3qLJPw5MVpHUewsbP2m/0/*)#dkgvr5hm");
 /// # Ok::<_, Box<dyn std::error::Error>>(())
 /// ```
@@ -454,10 +455,9 @@ impl<K: DerivableKey<Tap>> DescriptorTemplate for Bip86<K> {
 /// # use std::str::FromStr;
 /// # use bdk::bitcoin::{PrivateKey, Network};
 /// # use bdk::{Wallet,  KeychainKind};
-/// # use bdk::wallet::AddressIndex::New;
 /// use bdk::template::Bip86Public;
 ///
-/// let key = bitcoin::bip32::ExtendedPubKey::from_str("tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q")?;
+/// let key = bitcoin::bip32::Xpub::from_str("tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q")?;
 /// let fingerprint = bitcoin::bip32::Fingerprint::from_str("c55b303f")?;
 /// let mut wallet = Wallet::new_no_persist(
 ///     Bip86Public(key.clone(), fingerprint, KeychainKind::External),
@@ -465,7 +465,7 @@ impl<K: DerivableKey<Tap>> DescriptorTemplate for Bip86<K> {
 ///     Network::Testnet,
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New).to_string(), "tb1pwjp9f2k5n0xq73ecuu0c5njvgqr3vkh7yaylmpqvsuuaafymh0msvcmh37");
+/// assert_eq!(wallet.next_unused_address(KeychainKind::External)?.to_string(), "tb1pwjp9f2k5n0xq73ecuu0c5njvgqr3vkh7yaylmpqvsuuaafymh0msvcmh37");
 /// assert_eq!(wallet.public_descriptor(KeychainKind::External).unwrap().to_string(), "tr([c55b303f/86'/1'/0']tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q/0/*)#2p65srku");
 /// # Ok::<_, Box<dyn std::error::Error>>(())
 /// ```
@@ -567,7 +567,7 @@ mod test {
     fn test_bip44_template_cointype() {
         use bitcoin::bip32::ChildNumber::{self, Hardened};
 
-        let xprvkey = bitcoin::bip32::ExtendedPrivKey::from_str("xprv9s21ZrQH143K2fpbqApQL69a4oKdGVnVN52R82Ft7d1pSqgKmajF62acJo3aMszZb6qQ22QsVECSFxvf9uyxFUvFYQMq3QbtwtRSMjLAhMf").unwrap();
+        let xprvkey = bitcoin::bip32::Xpriv::from_str("xprv9s21ZrQH143K2fpbqApQL69a4oKdGVnVN52R82Ft7d1pSqgKmajF62acJo3aMszZb6qQ22QsVECSFxvf9uyxFUvFYQMq3QbtwtRSMjLAhMf").unwrap();
         assert_eq!(Network::Bitcoin, xprvkey.network);
         let xdesc = Bip44(xprvkey, KeychainKind::Internal)
             .build(Network::Bitcoin)
@@ -575,13 +575,13 @@ mod test {
 
         if let ExtendedDescriptor::Pkh(pkh) = xdesc.0 {
             let path: Vec<ChildNumber> = pkh.into_inner().full_derivation_path().unwrap().into();
-            let purpose = path.get(0).unwrap();
+            let purpose = path.first().unwrap();
             assert_matches!(purpose, Hardened { index: 44 });
             let coin_type = path.get(1).unwrap();
             assert_matches!(coin_type, Hardened { index: 0 });
         }
 
-        let tprvkey = bitcoin::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let tprvkey = bitcoin::bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         assert_eq!(Network::Testnet, tprvkey.network);
         let tdesc = Bip44(tprvkey, KeychainKind::Internal)
             .build(Network::Testnet)
@@ -589,7 +589,7 @@ mod test {
 
         if let ExtendedDescriptor::Pkh(pkh) = tdesc.0 {
             let path: Vec<ChildNumber> = pkh.into_inner().full_derivation_path().unwrap().into();
-            let purpose = path.get(0).unwrap();
+            let purpose = path.first().unwrap();
             assert_matches!(purpose, Hardened { index: 44 });
             let coin_type = path.get(1).unwrap();
             assert_matches!(coin_type, Hardened { index: 1 });
@@ -740,7 +740,7 @@ mod test {
     // BIP44 `pkh(key/44'/0'/0'/{0,1}/*)`
     #[test]
     fn test_bip44_template() {
-        let prvkey = bitcoin::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let prvkey = bitcoin::bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         check(
             Bip44(prvkey, KeychainKind::External).build(Network::Bitcoin),
             false,
@@ -770,7 +770,7 @@ mod test {
     // BIP44 public `pkh(key/{0,1}/*)`
     #[test]
     fn test_bip44_public_template() {
-        let pubkey = bitcoin::bip32::ExtendedPubKey::from_str("tpubDDDzQ31JkZB7VxUr9bjvBivDdqoFLrDPyLWtLapArAi51ftfmCb2DPxwLQzX65iNcXz1DGaVvyvo6JQ6rTU73r2gqdEo8uov9QKRb7nKCSU").unwrap();
+        let pubkey = bitcoin::bip32::Xpub::from_str("tpubDDDzQ31JkZB7VxUr9bjvBivDdqoFLrDPyLWtLapArAi51ftfmCb2DPxwLQzX65iNcXz1DGaVvyvo6JQ6rTU73r2gqdEo8uov9QKRb7nKCSU").unwrap();
         let fingerprint = bitcoin::bip32::Fingerprint::from_str("c55b303f").unwrap();
         check(
             Bip44Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
@@ -801,7 +801,7 @@ mod test {
     // BIP49 `sh(wpkh(key/49'/0'/0'/{0,1}/*))`
     #[test]
     fn test_bip49_template() {
-        let prvkey = bitcoin::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let prvkey = bitcoin::bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         check(
             Bip49(prvkey, KeychainKind::External).build(Network::Bitcoin),
             true,
@@ -831,7 +831,7 @@ mod test {
     // BIP49 public `sh(wpkh(key/{0,1}/*))`
     #[test]
     fn test_bip49_public_template() {
-        let pubkey = bitcoin::bip32::ExtendedPubKey::from_str("tpubDC49r947KGK52X5rBWS4BLs5m9SRY3pYHnvRrm7HcybZ3BfdEsGFyzCMzayi1u58eT82ZeyFZwH7DD6Q83E3fM9CpfMtmnTygnLfP59jL9L").unwrap();
+        let pubkey = bitcoin::bip32::Xpub::from_str("tpubDC49r947KGK52X5rBWS4BLs5m9SRY3pYHnvRrm7HcybZ3BfdEsGFyzCMzayi1u58eT82ZeyFZwH7DD6Q83E3fM9CpfMtmnTygnLfP59jL9L").unwrap();
         let fingerprint = bitcoin::bip32::Fingerprint::from_str("c55b303f").unwrap();
         check(
             Bip49Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
@@ -862,7 +862,7 @@ mod test {
     // BIP84 `wpkh(key/84'/0'/0'/{0,1}/*)`
     #[test]
     fn test_bip84_template() {
-        let prvkey = bitcoin::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        let prvkey = bitcoin::bip32::Xpriv::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         check(
             Bip84(prvkey, KeychainKind::External).build(Network::Bitcoin),
             true,
@@ -892,7 +892,7 @@ mod test {
     // BIP84 public `wpkh(key/{0,1}/*)`
     #[test]
     fn test_bip84_public_template() {
-        let pubkey = bitcoin::bip32::ExtendedPubKey::from_str("tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q").unwrap();
+        let pubkey = bitcoin::bip32::Xpub::from_str("tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q").unwrap();
         let fingerprint = bitcoin::bip32::Fingerprint::from_str("c55b303f").unwrap();
         check(
             Bip84Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
@@ -924,7 +924,7 @@ mod test {
     // Used addresses in test vector in https://github.com/bitcoin/bips/blob/master/bip-0086.mediawiki
     #[test]
     fn test_bip86_template() {
-        let prvkey = bitcoin::bip32::ExtendedPrivKey::from_str("xprv9s21ZrQH143K3GJpoapnV8SFfukcVBSfeCficPSGfubmSFDxo1kuHnLisriDvSnRRuL2Qrg5ggqHKNVpxR86QEC8w35uxmGoggxtQTPvfUu").unwrap();
+        let prvkey = bitcoin::bip32::Xpriv::from_str("xprv9s21ZrQH143K3GJpoapnV8SFfukcVBSfeCficPSGfubmSFDxo1kuHnLisriDvSnRRuL2Qrg5ggqHKNVpxR86QEC8w35uxmGoggxtQTPvfUu").unwrap();
         check(
             Bip86(prvkey, KeychainKind::External).build(Network::Bitcoin),
             false,
@@ -955,7 +955,7 @@ mod test {
     // Used addresses in test vector in https://github.com/bitcoin/bips/blob/master/bip-0086.mediawiki
     #[test]
     fn test_bip86_public_template() {
-        let pubkey = bitcoin::bip32::ExtendedPubKey::from_str("xpub6BgBgsespWvERF3LHQu6CnqdvfEvtMcQjYrcRzx53QJjSxarj2afYWcLteoGVky7D3UKDP9QyrLprQ3VCECoY49yfdDEHGCtMMj92pReUsQ").unwrap();
+        let pubkey = bitcoin::bip32::Xpub::from_str("xpub6BgBgsespWvERF3LHQu6CnqdvfEvtMcQjYrcRzx53QJjSxarj2afYWcLteoGVky7D3UKDP9QyrLprQ3VCECoY49yfdDEHGCtMMj92pReUsQ").unwrap();
         let fingerprint = bitcoin::bip32::Fingerprint::from_str("73c5da0a").unwrap();
         check(
             Bip86Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),

crates/bdk/src/keys/bip39.rs

@@ -57,7 +57,7 @@ pub type MnemonicWithPassphrase = (Mnemonic, Option<String>);
 #[cfg_attr(docsrs, doc(cfg(feature = "keys-bip39")))]
 impl<Ctx: ScriptContext> DerivableKey<Ctx> for Seed {
     fn into_extended_key(self) -> Result<ExtendedKey<Ctx>, KeyError> {
-        Ok(bip32::ExtendedPrivKey::new_master(Network::Bitcoin, &self[..])?.into())
+        Ok(bip32::Xpriv::new_master(Network::Bitcoin, &self[..])?.into())
     }
 
     fn into_descriptor_key(

crates/bdk/src/keys/mod.rs

@@ -110,7 +110,7 @@ impl<Ctx: ScriptContext> DescriptorKey<Ctx> {
                 Ok((public, KeyMap::default(), valid_networks))
             }
             DescriptorKey::Secret(secret, valid_networks, _) => {
-                let mut key_map = KeyMap::with_capacity(1);
+                let mut key_map = KeyMap::new();
 
                 let public = secret
                     .to_public(secp)
@@ -309,15 +309,15 @@ pub trait IntoDescriptorKey<Ctx: ScriptContext>: Sized {
 
 /// Enum for extended keys that can be either `xprv` or `xpub`
 ///
-/// An instance of [`ExtendedKey`] can be constructed from an [`ExtendedPrivKey`](bip32::ExtendedPrivKey)
-/// or an [`ExtendedPubKey`](bip32::ExtendedPubKey) by using the `From` trait.
+/// An instance of [`ExtendedKey`] can be constructed from an [`Xpriv`](bip32::Xpriv)
+/// or an [`Xpub`](bip32::Xpub) by using the `From` trait.
 ///
 /// Defaults to the [`Legacy`](miniscript::Legacy) context.
 pub enum ExtendedKey<Ctx: ScriptContext = miniscript::Legacy> {
     /// A private extended key, aka an `xprv`
-    Private((bip32::ExtendedPrivKey, PhantomData<Ctx>)),
+    Private((bip32::Xpriv, PhantomData<Ctx>)),
     /// A public extended key, aka an `xpub`
-    Public((bip32::ExtendedPubKey, PhantomData<Ctx>)),
+    Public((bip32::Xpub, PhantomData<Ctx>)),
 }
 
 impl<Ctx: ScriptContext> ExtendedKey<Ctx> {
@@ -329,9 +329,9 @@ impl<Ctx: ScriptContext> ExtendedKey<Ctx> {
         }
     }
 
-    /// Transform the [`ExtendedKey`] into an [`ExtendedPrivKey`](bip32::ExtendedPrivKey) for the
+    /// Transform the [`ExtendedKey`] into an [`Xpriv`](bip32::Xpriv) for the
     /// given [`Network`], if the key contains the private data
-    pub fn into_xprv(self, network: Network) -> Option<bip32::ExtendedPrivKey> {
+    pub fn into_xprv(self, network: Network) -> Option<bip32::Xpriv> {
         match self {
             ExtendedKey::Private((mut xprv, _)) => {
                 xprv.network = network;
@@ -341,15 +341,15 @@ impl<Ctx: ScriptContext> ExtendedKey<Ctx> {
         }
     }
 
-    /// Transform the [`ExtendedKey`] into an [`ExtendedPubKey`](bip32::ExtendedPubKey) for the
+    /// Transform the [`ExtendedKey`] into an [`Xpub`](bip32::Xpub) for the
     /// given [`Network`]
     pub fn into_xpub<C: Signing>(
         self,
         network: bitcoin::Network,
         secp: &Secp256k1<C>,
-    ) -> bip32::ExtendedPubKey {
+    ) -> bip32::Xpub {
         let mut xpub = match self {
-            ExtendedKey::Private((xprv, _)) => bip32::ExtendedPubKey::from_priv(secp, &xprv),
+            ExtendedKey::Private((xprv, _)) => bip32::Xpub::from_priv(secp, &xprv),
             ExtendedKey::Public((xpub, _)) => xpub,
         };
 
@@ -358,14 +358,14 @@ impl<Ctx: ScriptContext> ExtendedKey<Ctx> {
     }
 }
 
-impl<Ctx: ScriptContext> From<bip32::ExtendedPubKey> for ExtendedKey<Ctx> {
-    fn from(xpub: bip32::ExtendedPubKey) -> Self {
+impl<Ctx: ScriptContext> From<bip32::Xpub> for ExtendedKey<Ctx> {
+    fn from(xpub: bip32::Xpub) -> Self {
         ExtendedKey::Public((xpub, PhantomData))
     }
 }
 
-impl<Ctx: ScriptContext> From<bip32::ExtendedPrivKey> for ExtendedKey<Ctx> {
-    fn from(xprv: bip32::ExtendedPrivKey) -> Self {
+impl<Ctx: ScriptContext> From<bip32::Xpriv> for ExtendedKey<Ctx> {
+    fn from(xprv: bip32::Xpriv) -> Self {
         ExtendedKey::Private((xprv, PhantomData))
     }
 }
@@ -383,8 +383,8 @@ impl<Ctx: ScriptContext> From<bip32::ExtendedPrivKey> for ExtendedKey<Ctx> {
 ///
 /// ## Examples
 ///
-/// Key types that can be directly converted into an [`ExtendedPrivKey`] or
-/// an [`ExtendedPubKey`] can implement only the required `into_extended_key()` method.
+/// Key types that can be directly converted into an [`Xpriv`] or
+/// an [`Xpub`] can implement only the required `into_extended_key()` method.
 ///
 /// ```
 /// use bdk::bitcoin;
@@ -399,7 +399,7 @@ impl<Ctx: ScriptContext> From<bip32::ExtendedPrivKey> for ExtendedKey<Ctx> {
 ///
 /// impl<Ctx: ScriptContext> DerivableKey<Ctx> for MyCustomKeyType {
 ///     fn into_extended_key(self) -> Result<ExtendedKey<Ctx>, KeyError> {
-///         let xprv = bip32::ExtendedPrivKey {
+///         let xprv = bip32::Xpriv {
 ///             network: self.network,
 ///             depth: 0,
 ///             parent_fingerprint: bip32::Fingerprint::default(),
@@ -415,7 +415,7 @@ impl<Ctx: ScriptContext> From<bip32::ExtendedPrivKey> for ExtendedKey<Ctx> {
 ///
 /// Types that don't internally encode the [`Network`] in which they are valid need some extra
 /// steps to override the set of valid networks, otherwise only the network specified in the
-/// [`ExtendedPrivKey`] or [`ExtendedPubKey`] will be considered valid.
+/// [`Xpriv`] or [`Xpub`] will be considered valid.
 ///
 /// ```
 /// use bdk::bitcoin;
@@ -431,7 +431,7 @@ impl<Ctx: ScriptContext> From<bip32::ExtendedPrivKey> for ExtendedKey<Ctx> {
 ///
 /// impl<Ctx: ScriptContext> DerivableKey<Ctx> for MyCustomKeyType {
 ///     fn into_extended_key(self) -> Result<ExtendedKey<Ctx>, KeyError> {
-///         let xprv = bip32::ExtendedPrivKey {
+///         let xprv = bip32::Xpriv {
 ///             network: bitcoin::Network::Bitcoin, // pick an arbitrary network here
 ///             depth: 0,
 ///             parent_fingerprint: bip32::Fingerprint::default(),
@@ -459,8 +459,8 @@ impl<Ctx: ScriptContext> From<bip32::ExtendedPrivKey> for ExtendedKey<Ctx> {
 /// ```
 ///
 /// [`DerivationPath`]: (bip32::DerivationPath)
-/// [`ExtendedPrivKey`]: (bip32::ExtendedPrivKey)
-/// [`ExtendedPubKey`]: (bip32::ExtendedPubKey)
+/// [`Xpriv`]: (bip32::Xpriv)
+/// [`Xpub`]: (bip32::Xpub)
 pub trait DerivableKey<Ctx: ScriptContext = miniscript::Legacy>: Sized {
     /// Consume `self` and turn it into an [`ExtendedKey`]
     #[cfg_attr(
@@ -520,13 +520,13 @@ impl<Ctx: ScriptContext> DerivableKey<Ctx> for ExtendedKey<Ctx> {
     }
 }
 
-impl<Ctx: ScriptContext> DerivableKey<Ctx> for bip32::ExtendedPubKey {
+impl<Ctx: ScriptContext> DerivableKey<Ctx> for bip32::Xpub {
     fn into_extended_key(self) -> Result<ExtendedKey<Ctx>, KeyError> {
         Ok(self.into())
     }
 }
 
-impl<Ctx: ScriptContext> DerivableKey<Ctx> for bip32::ExtendedPrivKey {
+impl<Ctx: ScriptContext> DerivableKey<Ctx> for bip32::Xpriv {
     fn into_extended_key(self) -> Result<ExtendedKey<Ctx>, KeyError> {
         Ok(self.into())
     }
@@ -670,7 +670,7 @@ where
 {
 }
 
-impl<Ctx: ScriptContext> GeneratableKey<Ctx> for bip32::ExtendedPrivKey {
+impl<Ctx: ScriptContext> GeneratableKey<Ctx> for bip32::Xpriv {
     type Entropy = [u8; 32];
 
     type Options = ();
@@ -681,7 +681,7 @@ impl<Ctx: ScriptContext> GeneratableKey<Ctx> for bip32::ExtendedPrivKey {
         entropy: Self::Entropy,
     ) -> Result<GeneratedKey<Self, Ctx>, Self::Error> {
         // pick a arbitrary network here, but say that we support all of them
-        let xprv = bip32::ExtendedPrivKey::new_master(Network::Bitcoin, entropy.as_ref())?;
+        let xprv = bip32::Xpriv::new_master(Network::Bitcoin, entropy.as_ref())?;
         Ok(GeneratedKey::new(xprv, any_network()))
     }
 }
@@ -971,7 +971,7 @@ pub mod test {
     #[test]
     fn test_keys_generate_xprv() {
         let generated_xprv: GeneratedKey<_, miniscript::Segwitv0> =
-            bip32::ExtendedPrivKey::generate_with_entropy_default(TEST_ENTROPY).unwrap();
+            bip32::Xpriv::generate_with_entropy_default(TEST_ENTROPY).unwrap();
 
         assert_eq!(generated_xprv.valid_networks, any_network());
         assert_eq!(generated_xprv.to_string(), "xprv9s21ZrQH143K4Xr1cJyqTvuL2FWR8eicgY9boWqMBv8MDVUZ65AXHnzBrK1nyomu6wdcabRgmGTaAKawvhAno1V5FowGpTLVx3jxzE5uk3Q");

crates/bdk/src/lib.rs

@@ -17,8 +17,6 @@ extern crate std;
 pub extern crate alloc;
 
 pub extern crate bitcoin;
-#[cfg(feature = "hardware-signer")]
-pub extern crate hwi;
 pub extern crate miniscript;
 extern crate serde;
 extern crate serde_json;

crates/bdk/src/psbt/mod.rs

@@ -9,11 +9,12 @@
 // You may not use this file except in accordance with one or both of these
 // licenses.
 
-//! Additional functions on the `rust-bitcoin` `PartiallySignedTransaction` structure.
+//! Additional functions on the `rust-bitcoin` `Psbt` structure.
 
-use crate::FeeRate;
 use alloc::vec::Vec;
-use bitcoin::psbt::PartiallySignedTransaction as Psbt;
+use bitcoin::Amount;
+use bitcoin::FeeRate;
+use bitcoin::Psbt;
 use bitcoin::TxOut;
 
 // TODO upstream the functions here to `rust-bitcoin`?
@@ -28,31 +29,23 @@ pub trait PsbtUtils {
     fn fee_amount(&self) -> Option<u64>;
 
     /// The transaction's fee rate. This value will only be accurate if calculated AFTER the
-    /// `PartiallySignedTransaction` is finalized and all witness/signature data is added to the
+    /// `Psbt` is finalized and all witness/signature data is added to the
     /// transaction.
     /// If the PSBT is missing a TxOut for an input returns None.
     fn fee_rate(&self) -> Option<FeeRate>;
 }
 
 impl PsbtUtils for Psbt {
-    #[allow(clippy::all)] // We want to allow `manual_map` but it is too new.
     fn get_utxo_for(&self, input_index: usize) -> Option<TxOut> {
         let tx = &self.unsigned_tx;
+        let input = self.inputs.get(input_index)?;
 
-        if input_index >= tx.input.len() {
-            return None;
-        }
-
-        if let Some(input) = self.inputs.get(input_index) {
-            if let Some(wit_utxo) = &input.witness_utxo {
-                Some(wit_utxo.clone())
-            } else if let Some(in_tx) = &input.non_witness_utxo {
-                Some(in_tx.output[tx.input[input_index].previous_output.vout as usize].clone())
-            } else {
-                None
-            }
-        } else {
-            None
+        match (&input.witness_utxo, &input.non_witness_utxo) {
+            (Some(_), _) => input.witness_utxo.clone(),
+            (_, Some(_)) => input.non_witness_utxo.as_ref().map(|in_tx| {
+                in_tx.output[tx.input[input_index].previous_output.vout as usize].clone()
+            }),
+            _ => None,
         }
     }
 
@@ -61,8 +54,13 @@ impl PsbtUtils for Psbt {
         let utxos: Option<Vec<TxOut>> = (0..tx.input.len()).map(|i| self.get_utxo_for(i)).collect();
 
         utxos.map(|inputs| {
-            let input_amount: u64 = inputs.iter().map(|i| i.value).sum();
-            let output_amount: u64 = self.unsigned_tx.output.iter().map(|o| o.value).sum();
+            let input_amount: u64 = inputs.iter().map(|i| i.value.to_sat()).sum();
+            let output_amount: u64 = self
+                .unsigned_tx
+                .output
+                .iter()
+                .map(|o| o.value.to_sat())
+                .sum();
             input_amount
                 .checked_sub(output_amount)
                 .expect("input amount must be greater than output amount")
@@ -71,9 +69,7 @@ impl PsbtUtils for Psbt {
 
     fn fee_rate(&self) -> Option<FeeRate> {
         let fee_amount = self.fee_amount();
-        fee_amount.map(|fee| {
-            let weight = self.clone().extract_tx().weight();
-            FeeRate::from_wu(fee, weight)
-        })
+        let weight = self.clone().extract_tx().ok()?.weight();
+        fee_amount.map(|fee| Amount::from_sat(fee) / weight)
     }
 }

crates/bdk/src/types.rs

@@ -11,11 +11,10 @@
 
 use alloc::boxed::Box;
 use core::convert::AsRef;
-use core::ops::Sub;
 
 use bdk_chain::ConfirmationTime;
-use bitcoin::blockdata::transaction::{OutPoint, TxOut};
-use bitcoin::{psbt, Weight};
+use bitcoin::blockdata::transaction::{OutPoint, Sequence, TxOut};
+use bitcoin::psbt;
 
 use serde::{Deserialize, Serialize};
 
@@ -47,116 +46,6 @@ impl AsRef<[u8]> for KeychainKind {
     }
 }
 
-/// Fee rate
-#[derive(Debug, Copy, Clone, PartialEq, PartialOrd)]
-// Internally stored as satoshi/vbyte
-pub struct FeeRate(f32);
-
-impl FeeRate {
-    /// Create a new instance checking the value provided
-    ///
-    /// ## Panics
-    ///
-    /// Panics if the value is not [normal](https://doc.rust-lang.org/std/primitive.f32.html#method.is_normal) (except if it's a positive zero) or negative.
-    fn new_checked(value: f32) -> Self {
-        assert!(value.is_normal() || value == 0.0);
-        assert!(value.is_sign_positive());
-
-        FeeRate(value)
-    }
-
-    /// Create a new instance of [`FeeRate`] given a float fee rate in sats/kwu
-    pub fn from_sat_per_kwu(sat_per_kwu: f32) -> Self {
-        FeeRate::new_checked(sat_per_kwu / 250.0_f32)
-    }
-
-    /// Create a new instance of [`FeeRate`] given a float fee rate in sats/kvb
-    pub fn from_sat_per_kvb(sat_per_kvb: f32) -> Self {
-        FeeRate::new_checked(sat_per_kvb / 1000.0_f32)
-    }
-
-    /// Create a new instance of [`FeeRate`] given a float fee rate in btc/kvbytes
-    ///
-    /// ## Panics
-    ///
-    /// Panics if the value is not [normal](https://doc.rust-lang.org/std/primitive.f32.html#method.is_normal) (except if it's a positive zero) or negative.
-    pub fn from_btc_per_kvb(btc_per_kvb: f32) -> Self {
-        FeeRate::new_checked(btc_per_kvb * 1e5)
-    }
-
-    /// Create a new instance of [`FeeRate`] given a float fee rate in satoshi/vbyte
-    ///
-    /// ## Panics
-    ///
-    /// Panics if the value is not [normal](https://doc.rust-lang.org/std/primitive.f32.html#method.is_normal) (except if it's a positive zero) or negative.
-    pub fn from_sat_per_vb(sat_per_vb: f32) -> Self {
-        FeeRate::new_checked(sat_per_vb)
-    }
-
-    /// Create a new [`FeeRate`] with the default min relay fee value
-    pub const fn default_min_relay_fee() -> Self {
-        FeeRate(1.0)
-    }
-
-    /// Calculate fee rate from `fee` and weight units (`wu`).
-    pub fn from_wu(fee: u64, wu: Weight) -> FeeRate {
-        Self::from_vb(fee, wu.to_vbytes_ceil() as usize)
-    }
-
-    /// Calculate fee rate from `fee` and `vbytes`.
-    pub fn from_vb(fee: u64, vbytes: usize) -> FeeRate {
-        let rate = fee as f32 / vbytes as f32;
-        Self::from_sat_per_vb(rate)
-    }
-
-    /// Return the value as satoshi/vbyte
-    pub fn as_sat_per_vb(&self) -> f32 {
-        self.0
-    }
-
-    /// Return the value as satoshi/kwu
-    pub fn sat_per_kwu(&self) -> f32 {
-        self.0 * 250.0_f32
-    }
-
-    /// Calculate absolute fee in Satoshis using size in weight units.
-    pub fn fee_wu(&self, wu: Weight) -> u64 {
-        self.fee_vb(wu.to_vbytes_ceil() as usize)
-    }
-
-    /// Calculate absolute fee in Satoshis using size in virtual bytes.
-    pub fn fee_vb(&self, vbytes: usize) -> u64 {
-        (self.as_sat_per_vb() * vbytes as f32).ceil() as u64
-    }
-}
-
-impl Default for FeeRate {
-    fn default() -> Self {
-        FeeRate::default_min_relay_fee()
-    }
-}
-
-impl Sub for FeeRate {
-    type Output = Self;
-
-    fn sub(self, other: FeeRate) -> Self::Output {
-        FeeRate(self.0 - other.0)
-    }
-}
-
-/// Trait implemented by types that can be used to measure weight units.
-pub trait Vbytes {
-    /// Convert weight units to virtual bytes.
-    fn vbytes(self) -> usize;
-}
-
-impl Vbytes for usize {
-    fn vbytes(self) -> usize {
-        // ref: https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#transaction-size-calculations
-        (self as f32 / 4.0).ceil() as usize
-    }
-}
-
 /// An unspent output owned by a [`Wallet`].
 ///
 /// [`Wallet`]: crate::Wallet
@@ -197,6 +86,8 @@ pub enum Utxo {
     Foreign {
         /// The location of the output.
         outpoint: OutPoint,
+        /// The nSequence value to set for this input.
+        sequence: Option<Sequence>,
         /// The information about the input we require to add it to a PSBT.
         // Box it to stop the type being too big.
         psbt_input: Box<psbt::Input>,
@@ -219,6 +110,7 @@ impl Utxo {
             Utxo::Foreign {
                 outpoint,
                 psbt_input,
+                ..
             } => {
                 if let Some(prev_tx) = &psbt_input.non_witness_utxo {
                     return &prev_tx.output[outpoint.vout as usize];
@@ -232,74 +124,12 @@ impl Utxo {
             }
         }
     }
-}
 
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn can_store_feerate_in_const() {
-        const _MIN_RELAY: FeeRate = FeeRate::default_min_relay_fee();
-    }
-
-    #[test]
-    #[should_panic]
-    fn test_invalid_feerate_neg_zero() {
-        let _ = FeeRate::from_sat_per_vb(-0.0);
-    }
-
-    #[test]
-    #[should_panic]
-    fn test_invalid_feerate_neg_value() {
-        let _ = FeeRate::from_sat_per_vb(-5.0);
-    }
-
-    #[test]
-    #[should_panic]
-    fn test_invalid_feerate_nan() {
-        let _ = FeeRate::from_sat_per_vb(f32::NAN);
-    }
-
-    #[test]
-    #[should_panic]
-    fn test_invalid_feerate_inf() {
-        let _ = FeeRate::from_sat_per_vb(f32::INFINITY);
-    }
-
-    #[test]
-    fn test_valid_feerate_pos_zero() {
-        let _ = FeeRate::from_sat_per_vb(0.0);
-    }
-
-    #[test]
-    fn test_fee_from_btc_per_kvb() {
-        let fee = FeeRate::from_btc_per_kvb(1e-5);
-        assert!((fee.as_sat_per_vb() - 1.0).abs() < f32::EPSILON);
-    }
-
-    #[test]
-    fn test_fee_from_sat_per_vbyte() {
-        let fee = FeeRate::from_sat_per_vb(1.0);
-        assert!((fee.as_sat_per_vb() - 1.0).abs() < f32::EPSILON);
-    }
-
-    #[test]
-    fn test_fee_default_min_relay_fee() {
-        let fee = FeeRate::default_min_relay_fee();
-        assert!((fee.as_sat_per_vb() - 1.0).abs() < f32::EPSILON);
-    }
-
-    #[test]
-    fn test_fee_from_sat_per_kvb() {
-        let fee = FeeRate::from_sat_per_kvb(1000.0);
-        assert!((fee.as_sat_per_vb() - 1.0).abs() < f32::EPSILON);
-    }
-
-    #[test]
-    fn test_fee_from_sat_per_kwu() {
-        let fee = FeeRate::from_sat_per_kwu(250.0);
-        assert!((fee.as_sat_per_vb() - 1.0).abs() < f32::EPSILON);
-        assert_eq!(fee.sat_per_kwu(), 250.0);
+    /// Get the sequence number if an explicit sequence number has to be set for this input.
+    pub fn sequence(&self) -> Option<Sequence> {
+        match self {
+            Utxo::Local(_) => None,
+            Utxo::Foreign { sequence, .. } => *sequence,
+        }
     }
 }

crates/bdk/src/wallet/coin_selection.rs

@@ -28,11 +28,10 @@
 //! # use bitcoin::*;
 //! # use bdk::wallet::{self, ChangeSet, coin_selection::*, coin_selection};
 //! # use bdk::wallet::error::CreateTxError;
-//! # use bdk_chain::PersistBackend;
+//! # use bdk_persist::PersistBackend;
 //! # use bdk::*;
 //! # use bdk::wallet::coin_selection::decide_change;
 //! # use anyhow::Error;
-//! # const TXIN_BASE_WEIGHT: usize = (32 + 4 + 4) * 4;
 //! #[derive(Debug)]
 //! struct AlwaysSpendEverything;
 //!
@@ -41,7 +40,7 @@
 //!         &self,
 //!         required_utxos: Vec<WeightedUtxo>,
 //!         optional_utxos: Vec<WeightedUtxo>,
-//!         fee_rate: bdk::FeeRate,
+//!         fee_rate: FeeRate,
 //!         target_amount: u64,
 //!         drain_script: &Script,
 //!     ) -> Result<CoinSelectionResult, coin_selection::Error> {
@@ -53,15 +52,17 @@
 //!             .scan(
 //!                 (&mut selected_amount, &mut additional_weight),
 //!                 |(selected_amount, additional_weight), weighted_utxo| {
-//!                     **selected_amount += weighted_utxo.utxo.txout().value;
+//!                     **selected_amount += weighted_utxo.utxo.txout().value.to_sat();
 //!                     **additional_weight += Weight::from_wu(
-//!                         (TXIN_BASE_WEIGHT + weighted_utxo.satisfaction_weight) as u64,
+//!                         (TxIn::default().segwit_weight().to_wu()
+//!                             + weighted_utxo.satisfaction_weight as u64)
+//!                             as u64,
 //!                     );
 //!                     Some(weighted_utxo.utxo)
 //!                 },
 //!             )
 //!             .collect::<Vec<_>>();
-//!         let additional_fees = fee_rate.fee_wu(additional_weight);
+//!         let additional_fees = (fee_rate * additional_weight).to_sat();
 //!         let amount_needed_with_fees = additional_fees + target_amount;
 //!         if selected_amount < amount_needed_with_fees {
 //!             return Err(coin_selection::Error::InsufficientFunds {
@@ -91,7 +92,7 @@
 //!     .unwrap();
 //! let psbt = {
 //!     let mut builder = wallet.build_tx().coin_selection(AlwaysSpendEverything);
-//!     builder.add_recipient(to_address.script_pubkey(), 50_000);
+//!     builder.add_recipient(to_address.script_pubkey(), Amount::from_sat(50_000));
 //!     builder.finish()?
 //! };
 //!
@@ -100,13 +101,16 @@
 //! # Ok::<(), anyhow::Error>(())
 //! ```
 
-use crate::types::FeeRate;
+use crate::chain::collections::HashSet;
 use crate::wallet::utils::IsDust;
 use crate::Utxo;
 use crate::WeightedUtxo;
+use bitcoin::FeeRate;
 
 use alloc::vec::Vec;
 use bitcoin::consensus::encode::serialize;
+use bitcoin::OutPoint;
+use bitcoin::TxIn;
 use bitcoin::{Script, Weight};
 
 use core::convert::TryInto;
@@ -117,10 +121,6 @@ use rand::seq::SliceRandom;
 /// overridden
 pub type DefaultCoinSelectionAlgorithm = BranchAndBoundCoinSelection;
 
-// Base weight of a Txin, not counting the weight needed for satisfying it.
-// prev_txid (32 bytes) + prev_vout (4 bytes) + sequence (4 bytes)
-pub(crate) const TXIN_BASE_WEIGHT: usize = (32 + 4 + 4) * 4;
-
 /// Errors that can be thrown by the [`coin_selection`](crate::wallet::coin_selection) module
 #[derive(Debug)]
 pub enum Error {
@@ -193,7 +193,7 @@ pub struct CoinSelectionResult {
 impl CoinSelectionResult {
     /// The total value of the inputs selected.
     pub fn selected_amount(&self) -> u64 {
-        self.selected.iter().map(|u| u.txout().value).sum()
+        self.selected.iter().map(|u| u.txout().value.to_sat()).sum()
     }
 
     /// The total value of the inputs selected from the local wallet.
@@ -201,7 +201,7 @@ impl CoinSelectionResult {
         self.selected
             .iter()
             .filter_map(|u| match u {
-                Utxo::Local(_) => Some(u.txout().value),
+                Utxo::Local(_) => Some(u.txout().value.to_sat()),
                 _ => None,
             })
             .sum()
@@ -311,7 +311,8 @@ impl CoinSelectionAlgorithm for OldestFirstCoinSelection {
 pub fn decide_change(remaining_amount: u64, fee_rate: FeeRate, drain_script: &Script) -> Excess {
     // drain_output_len = size(len(script_pubkey)) + len(script_pubkey) + size(output_value)
     let drain_output_len = serialize(drain_script).len() + 8usize;
-    let change_fee = fee_rate.fee_vb(drain_output_len);
+    let change_fee =
+        (fee_rate * Weight::from_vb(drain_output_len as u64).expect("overflow occurred")).to_sat();
     let drain_val = remaining_amount.saturating_sub(change_fee);
 
     if drain_val.is_dust(drain_script) {
@@ -342,10 +343,13 @@ fn select_sorted_utxos(
             (&mut selected_amount, &mut fee_amount),
             |(selected_amount, fee_amount), (must_use, weighted_utxo)| {
                 if must_use || **selected_amount < target_amount + **fee_amount {
-                    **fee_amount += fee_rate.fee_wu(Weight::from_wu(
-                        (TXIN_BASE_WEIGHT + weighted_utxo.satisfaction_weight) as u64,
-                    ));
-                    **selected_amount += weighted_utxo.utxo.txout().value;
+                    **fee_amount += (fee_rate
+                        * Weight::from_wu(
+                            TxIn::default().segwit_weight().to_wu()
+                                + weighted_utxo.satisfaction_weight as u64,
+                        ))
+                    .to_sat();
+                    **selected_amount += weighted_utxo.utxo.txout().value.to_sat();
                     Some(weighted_utxo.utxo)
                 } else {
                     None
@@ -385,10 +389,12 @@ struct OutputGroup {
 
 impl OutputGroup {
     fn new(weighted_utxo: WeightedUtxo, fee_rate: FeeRate) -> Self {
-        let fee = fee_rate.fee_wu(Weight::from_wu(
-            (TXIN_BASE_WEIGHT + weighted_utxo.satisfaction_weight) as u64,
-        ));
-        let effective_value = weighted_utxo.utxo.txout().value as i64 - fee as i64;
+        let fee = (fee_rate
+            * Weight::from_wu(
+                TxIn::default().segwit_weight().to_wu() + weighted_utxo.satisfaction_weight as u64,
+            ))
+        .to_sat();
+        let effective_value = weighted_utxo.utxo.txout().value.to_sat() as i64 - fee as i64;
         OutputGroup {
             weighted_utxo,
             fee,
@@ -454,7 +460,8 @@ impl CoinSelectionAlgorithm for BranchAndBoundCoinSelection {
             .iter()
             .fold(0, |acc, x| acc + x.effective_value);
 
-        let cost_of_change = self.size_of_change as f32 * fee_rate.as_sat_per_vb();
+        let cost_of_change =
+            (Weight::from_vb(self.size_of_change).expect("overflow occurred") * fee_rate).to_sat();
 
         // `curr_value` and `curr_available_value` are both the sum of *effective_values* of
         // the UTXOs. For the optional UTXOs (curr_available_value) we filter out UTXOs with
@@ -478,7 +485,7 @@ impl CoinSelectionAlgorithm for BranchAndBoundCoinSelection {
                     .chain(optional_utxos.iter())
                     .fold((0, 0), |(mut fees, mut value), utxo| {
                         fees += utxo.fee;
-                        value += utxo.weighted_utxo.utxo.txout().value;
+                        value += utxo.weighted_utxo.utxo.txout().value.to_sat();
 
                         (fees, value)
                     });
@@ -545,7 +552,7 @@ impl BranchAndBoundCoinSelection {
         mut curr_value: i64,
         mut curr_available_value: i64,
         target_amount: i64,
-        cost_of_change: f32,
+        cost_of_change: u64,
         drain_script: &Script,
         fee_rate: FeeRate,
     ) -> Result<CoinSelectionResult, Error> {
@@ -582,7 +589,7 @@ impl BranchAndBoundCoinSelection {
                 // If we found a solution better than the previous one, or if there wasn't previous
                 // solution, update the best solution
                 if best_selection_value.is_none() || curr_value < best_selection_value.unwrap() {
-                    best_selection = current_selection.clone();
+                    best_selection.clone_from(&current_selection);
                     best_selection_value = Some(curr_value);
                 }
 
@@ -711,25 +718,44 @@ impl BranchAndBoundCoinSelection {
     }
 }
 
+/// Remove duplicate UTXOs.
+///
+/// If a UTXO appears in both `required` and `optional`, the appearance in `required` is kept.
+pub(crate) fn filter_duplicates<I>(required: I, optional: I) -> (I, I)
+where
+    I: IntoIterator<Item = WeightedUtxo> + FromIterator<WeightedUtxo>,
+{
+    let mut visited = HashSet::<OutPoint>::new();
+    let required = required
+        .into_iter()
+        .filter(|utxo| visited.insert(utxo.utxo.outpoint()))
+        .collect::<I>();
+    let optional = optional
+        .into_iter()
+        .filter(|utxo| visited.insert(utxo.utxo.outpoint()))
+        .collect::<I>();
+    (required, optional)
+}
+
 #[cfg(test)]
 mod test {
     use assert_matches::assert_matches;
     use core::str::FromStr;
 
     use bdk_chain::ConfirmationTime;
-    use bitcoin::{OutPoint, ScriptBuf, TxOut};
+    use bitcoin::{Amount, ScriptBuf, TxIn, TxOut};
 
     use super::*;
     use crate::types::*;
-    use crate::wallet::Vbytes;
+    use crate::wallet::coin_selection::filter_duplicates;
 
     use rand::rngs::StdRng;
     use rand::seq::SliceRandom;
     use rand::{Rng, RngCore, SeedableRng};
 
-    // n. of items on witness (1WU) + signature len (1WU) + signature and sighash (72WU)
-    // + pubkey len (1WU) + pubkey (33WU) + script sig len (1 byte, 4WU)
-    const P2WPKH_SATISFACTION_SIZE: usize = 1 + 1 + 72 + 1 + 33 + 4;
+    // signature len (1WU) + signature and sighash (72WU)
+    // + pubkey len (1WU) + pubkey (33WU)
+    const P2WPKH_SATISFACTION_SIZE: usize = 1 + 72 + 1 + 33;
 
     const FEE_AMOUNT: u64 = 50;
 
@@ -745,7 +771,7 @@ mod test {
             utxo: Utxo::Local(LocalOutput {
                 outpoint,
                 txout: TxOut {
-                    value,
+                    value: Amount::from_sat(value),
                     script_pubkey: ScriptBuf::new(),
                 },
                 keychain: KeychainKind::External,
@@ -799,16 +825,17 @@ mod test {
 
     fn generate_random_utxos(rng: &mut StdRng, utxos_number: usize) -> Vec<WeightedUtxo> {
         let mut res = Vec::new();
-        for _ in 0..utxos_number {
+        for i in 0..utxos_number {
             res.push(WeightedUtxo {
                 satisfaction_weight: P2WPKH_SATISFACTION_SIZE,
                 utxo: Utxo::Local(LocalOutput {
-                    outpoint: OutPoint::from_str(
-                        "ebd9813ecebc57ff8f30797de7c205e3c7498ca950ea4341ee51a685ff2fa30a:0",
-                    )
+                    outpoint: OutPoint::from_str(&format!(
+                        "ebd9813ecebc57ff8f30797de7c205e3c7498ca950ea4341ee51a685ff2fa30a:{}",
+                        i
+                    ))
                     .unwrap(),
                     txout: TxOut {
-                        value: rng.gen_range(0..200000000),
+                        value: Amount::from_sat(rng.gen_range(0..200000000)),
                         script_pubkey: ScriptBuf::new(),
                     },
                     keychain: KeychainKind::External,
@@ -829,24 +856,26 @@ mod test {
     }
 
     fn generate_same_value_utxos(utxos_value: u64, utxos_number: usize) -> Vec<WeightedUtxo> {
-        let utxo = WeightedUtxo {
-            satisfaction_weight: P2WPKH_SATISFACTION_SIZE,
-            utxo: Utxo::Local(LocalOutput {
-                outpoint: OutPoint::from_str(
-                    "ebd9813ecebc57ff8f30797de7c205e3c7498ca950ea4341ee51a685ff2fa30a:0",
-                )
-                .unwrap(),
-                txout: TxOut {
-                    value: utxos_value,
-                    script_pubkey: ScriptBuf::new(),
-                },
-                keychain: KeychainKind::External,
-                is_spent: false,
-                derivation_index: 42,
-                confirmation_time: ConfirmationTime::Unconfirmed { last_seen: 0 },
-            }),
-        };
-        vec![utxo; utxos_number]
+        (0..utxos_number)
+            .map(|i| WeightedUtxo {
+                satisfaction_weight: P2WPKH_SATISFACTION_SIZE,
+                utxo: Utxo::Local(LocalOutput {
+                    outpoint: OutPoint::from_str(&format!(
+                        "ebd9813ecebc57ff8f30797de7c205e3c7498ca950ea4341ee51a685ff2fa30a:{}",
+                        i
+                    ))
+                    .unwrap(),
+                    txout: TxOut {
+                        value: Amount::from_sat(utxos_value),
+                        script_pubkey: ScriptBuf::new(),
+                    },
+                    keychain: KeychainKind::External,
+                    is_spent: false,
+                    derivation_index: 42,
+                    confirmation_time: ConfirmationTime::Unconfirmed { last_seen: 0 },
+                }),
+            })
+            .collect()
     }
 
     fn sum_random_utxos(mut rng: &mut StdRng, utxos: &mut Vec<WeightedUtxo>) -> u64 {
@@ -854,7 +883,7 @@ mod test {
         utxos.shuffle(&mut rng);
         utxos[..utxos_picked_len]
             .iter()
-            .map(|u| u.utxo.txout().value)
+            .map(|u| u.utxo.txout().value.to_sat())
             .sum()
     }
 
@@ -868,7 +897,7 @@ mod test {
             .coin_select(
                 utxos,
                 vec![],
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -889,7 +918,7 @@ mod test {
             .coin_select(
                 utxos,
                 vec![],
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -910,7 +939,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -932,7 +961,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -950,7 +979,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1000.0),
+                FeeRate::from_sat_per_vb_unchecked(1000),
                 target_amount,
                 &drain_script,
             )
@@ -967,7 +996,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -988,7 +1017,7 @@ mod test {
             .coin_select(
                 utxos,
                 vec![],
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -1009,7 +1038,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -1031,7 +1060,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -1043,14 +1072,18 @@ mod test {
     fn test_oldest_first_coin_selection_insufficient_funds_high_fees() {
         let utxos = get_oldest_first_test_utxos();
 
-        let target_amount: u64 = utxos.iter().map(|wu| wu.utxo.txout().value).sum::<u64>() - 50;
+        let target_amount: u64 = utxos
+            .iter()
+            .map(|wu| wu.utxo.txout().value.to_sat())
+            .sum::<u64>()
+            - 50;
         let drain_script = ScriptBuf::default();
 
         OldestFirstCoinSelection
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1000.0),
+                FeeRate::from_sat_per_vb_unchecked(1000),
                 target_amount,
                 &drain_script,
             )
@@ -1071,7 +1104,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -1092,7 +1125,7 @@ mod test {
             .coin_select(
                 utxos.clone(),
                 utxos,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -1113,7 +1146,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -1138,9 +1171,9 @@ mod test {
         ));
 
         // Defensive assertions, for sanity and in case someone changes the test utxos vector.
-        let amount: u64 = required.iter().map(|u| u.utxo.txout().value).sum();
+        let amount: u64 = required.iter().map(|u| u.utxo.txout().value.to_sat()).sum();
         assert_eq!(amount, 100_000);
-        let amount: u64 = optional.iter().map(|u| u.utxo.txout().value).sum();
+        let amount: u64 = optional.iter().map(|u| u.utxo.txout().value.to_sat()).sum();
         assert!(amount > 150_000);
         let drain_script = ScriptBuf::default();
 
@@ -1150,7 +1183,7 @@ mod test {
             .coin_select(
                 required,
                 optional,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -1172,7 +1205,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1.0),
+                FeeRate::from_sat_per_vb_unchecked(1),
                 target_amount,
                 &drain_script,
             )
@@ -1190,7 +1223,7 @@ mod test {
             .coin_select(
                 vec![],
                 utxos,
-                FeeRate::from_sat_per_vb(1000.0),
+                FeeRate::from_sat_per_vb_unchecked(1000),
                 target_amount,
                 &drain_script,
             )
@@ -1202,22 +1235,19 @@ mod test {
         let utxos = get_test_utxos();
         let drain_script = ScriptBuf::default();
         let target_amount = 99932; // first utxo's effective value
+        let feerate = FeeRate::BROADCAST_MIN;
 
         let result = BranchAndBoundCoinSelection::new(0)
-            .coin_select(
-                vec![],
-                utxos,
-                FeeRate::from_sat_per_vb(1.0),
-                target_amount,
-                &drain_script,
-            )
+            .coin_select(vec![], utxos, feerate, target_amount, &drain_script)
             .unwrap();
 
         assert_eq!(result.selected.len(), 1);
         assert_eq!(result.selected_amount(), 100_000);
-        let input_size = (TXIN_BASE_WEIGHT + P2WPKH_SATISFACTION_SIZE).vbytes();
+        let input_weight =
+            TxIn::default().segwit_weight().to_wu() + P2WPKH_SATISFACTION_SIZE as u64;
         // the final fee rate should be exactly the same as the fee rate given
-        assert!((1.0 - (result.fee_amount as f32 / input_size as f32)).abs() < f32::EPSILON);
+        let result_feerate = Amount::from_sat(result.fee_amount) / Weight::from_wu(input_weight);
+        assert_eq!(result_feerate, feerate);
     }
 
     #[test]
@@ -1233,7 +1263,7 @@ mod test {
                 .coin_select(
                     vec![],
                     optional_utxos,
-                    FeeRate::from_sat_per_vb(0.0),
+                    FeeRate::ZERO,
                     target_amount,
                     &drain_script,
                 )
@@ -1245,7 +1275,7 @@ mod test {
     #[test]
     #[should_panic(expected = "BnBNoExactMatch")]
     fn test_bnb_function_no_exact_match() {
-        let fee_rate = FeeRate::from_sat_per_vb(10.0);
+        let fee_rate = FeeRate::from_sat_per_vb_unchecked(10);
         let utxos: Vec<OutputGroup> = get_test_utxos()
             .into_iter()
             .map(|u| OutputGroup::new(u, fee_rate))
@@ -1254,7 +1284,7 @@ mod test {
         let curr_available_value = utxos.iter().fold(0, |acc, x| acc + x.effective_value);
 
         let size_of_change = 31;
-        let cost_of_change = size_of_change as f32 * fee_rate.as_sat_per_vb();
+        let cost_of_change = (Weight::from_vb_unchecked(size_of_change) * fee_rate).to_sat();
 
         let drain_script = ScriptBuf::default();
         let target_amount = 20_000 + FEE_AMOUNT;
@@ -1275,7 +1305,7 @@ mod test {
     #[test]
     #[should_panic(expected = "BnBTotalTriesExceeded")]
     fn test_bnb_function_tries_exceeded() {
-        let fee_rate = FeeRate::from_sat_per_vb(10.0);
+        let fee_rate = FeeRate::from_sat_per_vb_unchecked(10);
         let utxos: Vec<OutputGroup> = generate_same_value_utxos(100_000, 100_000)
             .into_iter()
             .map(|u| OutputGroup::new(u, fee_rate))
@@ -1284,7 +1314,7 @@ mod test {
         let curr_available_value = utxos.iter().fold(0, |acc, x| acc + x.effective_value);
 
         let size_of_change = 31;
-        let cost_of_change = size_of_change as f32 * fee_rate.as_sat_per_vb();
+        let cost_of_change = (Weight::from_vb_unchecked(size_of_change) * fee_rate).to_sat();
         let target_amount = 20_000 + FEE_AMOUNT;
 
         let drain_script = ScriptBuf::default();
@@ -1306,9 +1336,9 @@ mod test {
     // The match won't be exact but still in the range
     #[test]
     fn test_bnb_function_almost_exact_match_with_fees() {
-        let fee_rate = FeeRate::from_sat_per_vb(1.0);
+        let fee_rate = FeeRate::from_sat_per_vb_unchecked(1);
         let size_of_change = 31;
-        let cost_of_change = size_of_change as f32 * fee_rate.as_sat_per_vb();
+        let cost_of_change = (Weight::from_vb_unchecked(size_of_change) * fee_rate).to_sat();
 
         let utxos: Vec<_> = generate_same_value_utxos(50_000, 10)
             .into_iter()
@@ -1321,7 +1351,7 @@ mod test {
 
         // 2*(value of 1 utxo)  - 2*(1 utxo fees with 1.0sat/vbyte fee rate) -
         // cost_of_change + 5.
-        let target_amount = 2 * 50_000 - 2 * 67 - cost_of_change.ceil() as i64 + 5;
+        let target_amount = 2 * 50_000 - 2 * 67 - cost_of_change as i64 + 5;
 
         let drain_script = ScriptBuf::default();
 
@@ -1346,7 +1376,7 @@ mod test {
     fn test_bnb_function_exact_match_more_utxos() {
         let seed = [0; 32];
         let mut rng: StdRng = SeedableRng::from_seed(seed);
-        let fee_rate = FeeRate::from_sat_per_vb(0.0);
+        let fee_rate = FeeRate::ZERO;
 
         for _ in 0..200 {
             let optional_utxos: Vec<_> = generate_random_utxos(&mut rng, 40)
@@ -1372,7 +1402,7 @@ mod test {
                     curr_value,
                     curr_available_value,
                     target_amount,
-                    0.0,
+                    0,
                     &drain_script,
                     fee_rate,
                 )
@@ -1388,7 +1418,7 @@ mod test {
         let mut utxos = generate_random_utxos(&mut rng, 300);
         let target_amount = sum_random_utxos(&mut rng, &mut utxos) + FEE_AMOUNT;
 
-        let fee_rate = FeeRate::from_sat_per_vb(1.0);
+        let fee_rate = FeeRate::from_sat_per_vb_unchecked(1);
         let utxos: Vec<OutputGroup> = utxos
             .into_iter()
             .map(|u| OutputGroup::new(u, fee_rate))
@@ -1417,7 +1447,7 @@ mod test {
         let selection = BranchAndBoundCoinSelection::default().coin_select(
             vec![],
             utxos,
-            FeeRate::from_sat_per_vb(10.0),
+            FeeRate::from_sat_per_vb_unchecked(10),
             500_000,
             &drain_script,
         );
@@ -1436,14 +1466,14 @@ mod test {
         let utxos = get_test_utxos();
         let drain_script = ScriptBuf::default();
 
-        let (required, optional) = utxos
-            .into_iter()
-            .partition(|u| matches!(u, WeightedUtxo { utxo, .. } if utxo.txout().value < 1000));
+        let (required, optional) = utxos.into_iter().partition(
+            |u| matches!(u, WeightedUtxo { utxo, .. } if utxo.txout().value.to_sat() < 1000),
+        );
 
         let selection = BranchAndBoundCoinSelection::default().coin_select(
             required,
             optional,
-            FeeRate::from_sat_per_vb(10.0),
+            FeeRate::from_sat_per_vb_unchecked(10),
             500_000,
             &drain_script,
         );
@@ -1465,7 +1495,7 @@ mod test {
         let selection = BranchAndBoundCoinSelection::default().coin_select(
             utxos,
             vec![],
-            FeeRate::from_sat_per_vb(10_000.0),
+            FeeRate::from_sat_per_vb_unchecked(10_000),
             500_000,
             &drain_script,
         );
@@ -1478,4 +1508,95 @@ mod test {
             })
         );
     }
+
+    #[test]
+    fn test_filter_duplicates() {
+        fn utxo(txid: &str, value: u64) -> WeightedUtxo {
+            WeightedUtxo {
+                satisfaction_weight: 0,
+                utxo: Utxo::Local(LocalOutput {
+                    outpoint: OutPoint::new(bitcoin::hashes::Hash::hash(txid.as_bytes()), 0),
+                    txout: TxOut {
+                        value: Amount::from_sat(value),
+                        script_pubkey: ScriptBuf::new(),
+                    },
+                    keychain: KeychainKind::External,
+                    is_spent: false,
+                    derivation_index: 0,
+                    confirmation_time: ConfirmationTime::Confirmed {
+                        height: 12345,
+                        time: 12345,
+                    },
+                }),
+            }
+        }
+
+        fn to_utxo_vec(utxos: &[(&str, u64)]) -> Vec<WeightedUtxo> {
+            let mut v = utxos
+                .iter()
+                .map(|&(txid, value)| utxo(txid, value))
+                .collect::<Vec<_>>();
+            v.sort_by_key(|u| u.utxo.outpoint());
+            v
+        }
+
+        struct TestCase<'a> {
+            name: &'a str,
+            required: &'a [(&'a str, u64)],
+            optional: &'a [(&'a str, u64)],
+            exp_required: &'a [(&'a str, u64)],
+            exp_optional: &'a [(&'a str, u64)],
+        }
+
+        let test_cases = [
+            TestCase {
+                name: "no_duplicates",
+                required: &[("A", 1000), ("B", 2100)],
+                optional: &[("C", 1000)],
+                exp_required: &[("A", 1000), ("B", 2100)],
+                exp_optional: &[("C", 1000)],
+            },
+            TestCase {
+                name: "duplicate_required_utxos",
+                required: &[("A", 3000), ("B", 1200), ("C", 1234), ("A", 3000)],
+                optional: &[("D", 2100)],
+                exp_required: &[("A", 3000), ("B", 1200), ("C", 1234)],
+                exp_optional: &[("D", 2100)],
+            },
+            TestCase {
+                name: "duplicate_optional_utxos",
+                required: &[("A", 3000), ("B", 1200)],
+                optional: &[("C", 5000), ("D", 1300), ("C", 5000)],
+                exp_required: &[("A", 3000), ("B", 1200)],
+                exp_optional: &[("C", 5000), ("D", 1300)],
+            },
+            TestCase {
+                name: "duplicate_across_required_and_optional_utxos",
+                required: &[("A", 3000), ("B", 1200), ("C", 2100)],
+                optional: &[("A", 3000), ("D", 1200), ("E", 5000)],
+                exp_required: &[("A", 3000), ("B", 1200), ("C", 2100)],
+                exp_optional: &[("D", 1200), ("E", 5000)],
+            },
+        ];
+
+        for (i, t) in test_cases.into_iter().enumerate() {
+            println!("Case {}: {}", i, t.name);
+            let (required, optional) =
+                filter_duplicates(to_utxo_vec(t.required), to_utxo_vec(t.optional));
+            assert_eq!(
+                required,
+                to_utxo_vec(t.exp_required),
+                "[{}:{}] unexpected `required` result",
+                i,
+                t.name
+            );
+            assert_eq!(
+                optional,
+                to_utxo_vec(t.exp_optional),
+                "[{}:{}] unexpected `optional` result",
+                i,
+                t.name
+            );
+        }
+    }
 }

crates/bdk/src/wallet/error.rs

@@ -14,7 +14,7 @@
 use crate::descriptor::policy::PolicyError;
 use crate::descriptor::DescriptorError;
 use crate::wallet::coin_selection;
-use crate::{descriptor, FeeRate, KeychainKind};
+use crate::{descriptor, KeychainKind};
 use alloc::string::String;
 use bitcoin::{absolute, psbt, OutPoint, Sequence, Txid};
 use core::fmt;
@@ -47,11 +47,11 @@ impl std::error::Error for MiniscriptPsbtError {}
 /// Error returned from [`TxBuilder::finish`]
 ///
 /// [`TxBuilder::finish`]: crate::wallet::tx_builder::TxBuilder::finish
-pub enum CreateTxError<P> {
+pub enum CreateTxError {
     /// There was a problem with the descriptors passed in
     Descriptor(DescriptorError),
-    /// We were unable to write wallet data to the persistence backend
-    Persist(P),
+    /// We were unable to load wallet data from or write wallet data to the persistence backend
+    Persist(anyhow::Error),
     /// There was a problem while extracting and manipulating policies
     Policy(PolicyError),
     /// Spending policy is not compatible with this [`KeychainKind`]
@@ -83,8 +83,8 @@ pub enum CreateTxError<P> {
     },
     /// When bumping a tx the fee rate requested is lower than required
     FeeRateTooLow {
-        /// Required fee rate (satoshi/vbyte)
-        required: FeeRate,
+        /// Required fee rate
+        required: bitcoin::FeeRate,
     },
     /// `manually_selected_only` option is selected but no utxo has been passed
     NoUtxosSelected,
@@ -119,17 +119,14 @@ pub enum CreateTxError<P> {
     MiniscriptPsbt(MiniscriptPsbtError),
 }
 
-impl<P> fmt::Display for CreateTxError<P>
-where
-    P: fmt::Display,
-{
+impl fmt::Display for CreateTxError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Self::Descriptor(e) => e.fmt(f),
             Self::Persist(e) => {
                 write!(
                     f,
-                    "failed to write wallet data to persistence backend: {}",
+                    "failed to load wallet data from or write wallet data to persistence backend: {}",
                     e
                 )
             }
@@ -168,8 +165,10 @@ where
             CreateTxError::FeeRateTooLow { required } => {
                 write!(
                     f,
-                    "Fee rate too low: required {} sat/vbyte",
-                    required.as_sat_per_vb()
+                    // Note: alternate fmt as sat/vb (ceil) available in bitcoin-0.31
+                    //"Fee rate too low: required {required:#}"
+                    "Fee rate too low: required {} sat/vb",
+                    crate::floating_rate!(required)
                 )
             }
             CreateTxError::NoUtxosSelected => {
@@ -212,38 +211,38 @@ where
     }
 }
 
-impl<P> From<descriptor::error::Error> for CreateTxError<P> {
+impl From<descriptor::error::Error> for CreateTxError {
     fn from(err: descriptor::error::Error) -> Self {
         CreateTxError::Descriptor(err)
     }
 }
 
-impl<P> From<PolicyError> for CreateTxError<P> {
+impl From<PolicyError> for CreateTxError {
     fn from(err: PolicyError) -> Self {
         CreateTxError::Policy(err)
     }
 }
 
-impl<P> From<MiniscriptPsbtError> for CreateTxError<P> {
+impl From<MiniscriptPsbtError> for CreateTxError {
     fn from(err: MiniscriptPsbtError) -> Self {
         CreateTxError::MiniscriptPsbt(err)
     }
 }
 
-impl<P> From<psbt::Error> for CreateTxError<P> {
+impl From<psbt::Error> for CreateTxError {
     fn from(err: psbt::Error) -> Self {
         CreateTxError::Psbt(err)
     }
 }
 
-impl<P> From<coin_selection::Error> for CreateTxError<P> {
+impl From<coin_selection::Error> for CreateTxError {
     fn from(err: coin_selection::Error) -> Self {
         CreateTxError::CoinSelection(err)
     }
 }
 
 #[cfg(feature = "std")]
-impl<P: core::fmt::Display + core::fmt::Debug> std::error::Error for CreateTxError<P> {}
+impl std::error::Error for CreateTxError {}
 
 #[derive(Debug)]
 /// Error returned from [`Wallet::build_fee_bump`]

crates/bdk/src/wallet/export.rs

@@ -53,9 +53,9 @@
 //! # Ok::<_, Box<dyn std::error::Error>>(())
 //! ```
 
+use alloc::string::String;
+use core::fmt;
 use core::str::FromStr;
-
-use alloc::string::{String, ToString};
 use serde::{Deserialize, Serialize};
 
 use miniscript::descriptor::{ShInner, WshInner};
@@ -80,9 +80,9 @@ pub struct FullyNodedExport {
     pub label: String,
 }
 
-impl ToString for FullyNodedExport {
-    fn to_string(&self) -> String {
-        serde_json::to_string(self).unwrap()
+impl fmt::Display for FullyNodedExport {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", serde_json::to_string(self).unwrap())
     }
 }
 
@@ -110,8 +110,8 @@ impl FullyNodedExport {
     ///
     /// If the database is empty or `include_blockheight` is false, the `blockheight` field
     /// returned will be `0`.
-    pub fn export_wallet<D>(
-        wallet: &Wallet<D>,
+    pub fn export_wallet(
+        wallet: &Wallet,
         label: &str,
         include_blockheight: bool,
     ) -> Result<Self, &'static str> {
@@ -214,9 +214,10 @@ impl FullyNodedExport {
 mod test {
     use core::str::FromStr;
 
+    use crate::std::string::ToString;
     use bdk_chain::{BlockId, ConfirmationTime};
     use bitcoin::hashes::Hash;
-    use bitcoin::{BlockHash, Network, Transaction};
+    use bitcoin::{transaction, BlockHash, Network, Transaction};
 
     use super::*;
     use crate::wallet::Wallet;
@@ -225,12 +226,12 @@ mod test {
         descriptor: &str,
         change_descriptor: Option<&str>,
         network: Network,
-    ) -> Wallet<()> {
+    ) -> Wallet {
         let mut wallet = Wallet::new_no_persist(descriptor, change_descriptor, network).unwrap();
         let transaction = Transaction {
             input: vec![],
             output: vec![],
-            version: 0,
+            version: transaction::Version::non_standard(0),
             lock_time: bitcoin::absolute::LockTime::ZERO,
         };
         wallet

crates/bdk/src/wallet/hardwaresigner.rs

@@ -18,7 +18,7 @@
 //! # use bdk::signer::SignerOrdering;
 //! # use bdk::wallet::hardwaresigner::HWISigner;
 //! # use bdk::wallet::AddressIndex::New;
-//! # use bdk::{FeeRate, KeychainKind, SignOptions, Wallet};
+//! # use bdk::{KeychainKind, SignOptions, Wallet};
 //! # use hwi::HWIClient;
 //! # use std::sync::Arc;
 //! #
@@ -48,8 +48,8 @@
 //! ```
 
 use bitcoin::bip32::Fingerprint;
-use bitcoin::psbt::PartiallySignedTransaction;
 use bitcoin::secp256k1::{All, Secp256k1};
+use bitcoin::Psbt;
 
 use hwi::error::Error;
 use hwi::types::{HWIChain, HWIDevice};
@@ -87,7 +87,7 @@ impl SignerCommon for HWISigner {
 impl TransactionSigner for HWISigner {
     fn sign_transaction(
         &self,
-        psbt: &mut PartiallySignedTransaction,
+        psbt: &mut Psbt,
         _sign_options: &crate::SignOptions,
         _secp: &crate::wallet::utils::SecpCtx,
     ) -> Result<(), SignerError> {

crates/bdk/src/wallet/signer.rs

@@ -19,13 +19,12 @@
 //! # use core::str::FromStr;
 //! # use bitcoin::secp256k1::{Secp256k1, All};
 //! # use bitcoin::*;
-//! # use bitcoin::psbt;
 //! # use bdk::signer::*;
 //! # use bdk::*;
 //! # #[derive(Debug)]
 //! # struct CustomHSM;
 //! # impl CustomHSM {
-//! #     fn hsm_sign_input(&self, _psbt: &mut psbt::PartiallySignedTransaction, _input: usize) -> Result<(), SignerError> {
+//! #     fn hsm_sign_input(&self, _psbt: &mut Psbt, _input: usize) -> Result<(), SignerError> {
 //! #         Ok(())
 //! #     }
 //! #     fn connect() -> Self {
@@ -55,7 +54,7 @@
 //! impl InputSigner for CustomSigner {
 //!     fn sign_input(
 //!         &self,
-//!         psbt: &mut psbt::PartiallySignedTransaction,
+//!         psbt: &mut Psbt,
 //!         input_index: usize,
 //!         _sign_options: &SignOptions,
 //!         _secp: &Secp256k1<All>,
@@ -80,19 +79,20 @@
 //! ```
 
 use crate::collections::BTreeMap;
+use alloc::string::String;
 use alloc::sync::Arc;
 use alloc::vec::Vec;
 use core::cmp::Ordering;
 use core::fmt;
 use core::ops::{Bound::Included, Deref};
 
-use bitcoin::bip32::{ChildNumber, DerivationPath, ExtendedPrivKey, Fingerprint};
+use bitcoin::bip32::{ChildNumber, DerivationPath, Fingerprint, Xpriv};
 use bitcoin::hashes::hash160;
 use bitcoin::secp256k1::Message;
 use bitcoin::sighash::{EcdsaSighashType, TapSighash, TapSighashType};
 use bitcoin::{ecdsa, psbt, sighash, taproot};
 use bitcoin::{key::TapTweak, key::XOnlyPublicKey, secp256k1};
-use bitcoin::{PrivateKey, PublicKey};
+use bitcoin::{PrivateKey, Psbt, PublicKey};
 
 use miniscript::descriptor::{
     Descriptor, DescriptorMultiXKey, DescriptorPublicKey, DescriptorSecretKey, DescriptorXKey,
@@ -162,16 +162,10 @@ pub enum SignerError {
     SighashError(sighash::Error),
     /// Miniscript PSBT error
     MiniscriptPsbt(MiniscriptPsbtError),
-    /// Error while signing using hardware wallets
-    #[cfg(feature = "hardware-signer")]
-    HWIError(hwi::error::Error),
-}
-
-#[cfg(feature = "hardware-signer")]
-impl From<hwi::error::Error> for SignerError {
-    fn from(e: hwi::error::Error) -> Self {
-        SignerError::HWIError(e)
-    }
+    /// To be used only by external libraries implementing [`InputSigner`] or
+    /// [`TransactionSigner`], so that they can return their own custom errors, without having to
+    /// modify [`SignerError`] in BDK.
+    External(String),
 }
 
 impl From<sighash::Error> for SignerError {
@@ -196,8 +190,7 @@ impl fmt::Display for SignerError {
             Self::InvalidSighash => write!(f, "Invalid SIGHASH for the signing context in use"),
             Self::SighashError(err) => write!(f, "Error while computing the hash to sign: {}", err),
             Self::MiniscriptPsbt(err) => write!(f, "Miniscript PSBT error: {}", err),
-            #[cfg(feature = "hardware-signer")]
-            Self::HWIError(err) => write!(f, "Error while signing using hardware wallets: {}", err),
+            Self::External(err) => write!(f, "{}", err),
         }
     }
 }
@@ -221,7 +214,7 @@ pub enum SignerContext {
     },
 }
 
-/// Wrapper structure to pair a signer with its context
+/// Wrapper to pair a signer with its context
 #[derive(Debug, Clone)]
 pub struct SignerWrapper<S: Sized + fmt::Debug + Clone> {
     signer: S,
@@ -270,7 +263,7 @@ pub trait InputSigner: SignerCommon {
     /// Sign a single psbt input
     fn sign_input(
         &self,
-        psbt: &mut psbt::PartiallySignedTransaction,
+        psbt: &mut Psbt,
         input_index: usize,
         sign_options: &SignOptions,
         secp: &SecpCtx,
@@ -285,7 +278,7 @@ pub trait TransactionSigner: SignerCommon {
     /// Sign all the inputs of the psbt
     fn sign_transaction(
         &self,
-        psbt: &mut psbt::PartiallySignedTransaction,
+        psbt: &mut Psbt,
         sign_options: &SignOptions,
         secp: &SecpCtx,
     ) -> Result<(), SignerError>;
@@ -294,7 +287,7 @@ pub trait TransactionSigner: SignerCommon {
 impl<T: InputSigner> TransactionSigner for T {
     fn sign_transaction(
         &self,
-        psbt: &mut psbt::PartiallySignedTransaction,
+        psbt: &mut Psbt,
         sign_options: &SignOptions,
         secp: &SecpCtx,
     ) -> Result<(), SignerError> {
@@ -306,7 +299,7 @@ impl<T: InputSigner> TransactionSigner for T {
     }
 }
 
-impl SignerCommon for SignerWrapper<DescriptorXKey<ExtendedPrivKey>> {
+impl SignerCommon for SignerWrapper<DescriptorXKey<Xpriv>> {
     fn id(&self, secp: &SecpCtx) -> SignerId {
         SignerId::from(self.root_fingerprint(secp))
     }
@@ -316,10 +309,10 @@ impl SignerCommon for SignerWrapper<DescriptorXKey<ExtendedPrivKey>> {
     }
 }
 
-impl InputSigner for SignerWrapper<DescriptorXKey<ExtendedPrivKey>> {
+impl InputSigner for SignerWrapper<DescriptorXKey<Xpriv>> {
     fn sign_input(
         &self,
-        psbt: &mut psbt::PartiallySignedTransaction,
+        psbt: &mut Psbt,
         input_index: usize,
         sign_options: &SignOptions,
         secp: &SecpCtx,
@@ -402,7 +395,7 @@ fn multikey_to_xkeys<K: InnerXKey + Clone>(
         .collect()
 }
 
-impl SignerCommon for SignerWrapper<DescriptorMultiXKey<ExtendedPrivKey>> {
+impl SignerCommon for SignerWrapper<DescriptorMultiXKey<Xpriv>> {
     fn id(&self, secp: &SecpCtx) -> SignerId {
         SignerId::from(self.root_fingerprint(secp))
     }
@@ -412,10 +405,10 @@ impl SignerCommon for SignerWrapper<DescriptorMultiXKey<ExtendedPrivKey>> {
     }
 }
 
-impl InputSigner for SignerWrapper<DescriptorMultiXKey<ExtendedPrivKey>> {
+impl InputSigner for SignerWrapper<DescriptorMultiXKey<Xpriv>> {
     fn sign_input(
         &self,
-        psbt: &mut psbt::PartiallySignedTransaction,
+        psbt: &mut Psbt,
         input_index: usize,
         sign_options: &SignOptions,
         secp: &SecpCtx,
@@ -444,7 +437,7 @@ impl SignerCommon for SignerWrapper<PrivateKey> {
 impl InputSigner for SignerWrapper<PrivateKey> {
     fn sign_input(
         &self,
-        psbt: &mut psbt::PartiallySignedTransaction,
+        psbt: &mut Psbt,
         input_index: usize,
         sign_options: &SignOptions,
         secp: &SecpCtx,
@@ -583,7 +576,7 @@ fn sign_psbt_schnorr(
     hash_ty: TapSighashType,
     secp: &SecpCtx,
 ) {
-    let keypair = secp256k1::KeyPair::from_seckey_slice(secp, secret_key.as_ref()).unwrap();
+    let keypair = secp256k1::Keypair::from_seckey_slice(secp, secret_key.as_ref()).unwrap();
     let keypair = match leaf_hash {
         None => keypair
             .tap_tweak(secp, psbt_input.tap_merkle_root)
@@ -788,6 +781,16 @@ pub struct SignOptions {
     /// Defaults to `true` which will remove partial signatures during finalization.
     pub remove_partial_sigs: bool,
 
+    /// Whether to remove taproot specific fields from the PSBT on finalization.
+    ///
+    /// For inputs this includes the taproot internal key, merkle root, and individual
+    /// scripts and signatures. For both inputs and outputs it includes key origin info.
+    ///
+    /// Defaults to `true` which will remove all of the above mentioned fields when finalizing.
+    ///
+    /// See [`BIP371`](https://github.com/bitcoin/bips/blob/master/bip-0371.mediawiki) for details.
+    pub remove_taproot_extras: bool,
+
     /// Whether to try finalizing the PSBT after the inputs are signed.
     ///
     /// Defaults to `true` which will try finalizing PSBT after inputs are signed.
@@ -812,9 +815,10 @@ pub struct SignOptions {
 }
 
 /// Customize which taproot script-path leaves the signer should sign.
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Default, Debug, Clone, PartialEq, Eq)]
 pub enum TapLeavesOptions {
     /// The signer will sign all the leaves it has a key for.
+    #[default]
     All,
     /// The signer won't sign leaves other than the ones specified. Note that it could still ignore
     /// some of the specified leaves, if it doesn't have the right key to sign them.
@@ -825,13 +829,6 @@ pub enum TapLeavesOptions {
     None,
 }
 
-impl Default for TapLeavesOptions {
-    fn default() -> Self {
-        TapLeavesOptions::All
-    }
-}
-
-#[allow(clippy::derivable_impls)]
 impl Default for SignOptions {
     fn default() -> Self {
         SignOptions {
@@ -839,6 +836,7 @@ impl Default for SignOptions {
             assume_height: None,
             allow_all_sighashes: false,
             remove_partial_sigs: true,
+            remove_taproot_extras: true,
             try_finalize: true,
             tap_leaves_options: TapLeavesOptions::default(),
             sign_with_tap_internal_key: true,
@@ -853,7 +851,7 @@ pub(crate) trait ComputeSighash {
     type SighashType;
 
     fn sighash(
-        psbt: &psbt::PartiallySignedTransaction,
+        psbt: &Psbt,
         input_index: usize,
         extra: Self::Extra,
     ) -> Result<(Self::Sighash, Self::SighashType), SignerError>;
@@ -865,7 +863,7 @@ impl ComputeSighash for Legacy {
     type SighashType = EcdsaSighashType;
 
     fn sighash(
-        psbt: &psbt::PartiallySignedTransaction,
+        psbt: &Psbt,
         input_index: usize,
         _extra: (),
     ) -> Result<(Self::Sighash, Self::SighashType), SignerError> {
@@ -914,7 +912,7 @@ impl ComputeSighash for Segwitv0 {
     type SighashType = EcdsaSighashType;
 
     fn sighash(
-        psbt: &psbt::PartiallySignedTransaction,
+        psbt: &Psbt,
         input_index: usize,
         _extra: (),
     ) -> Result<(Self::Sighash, Self::SighashType), SignerError> {
@@ -925,7 +923,7 @@ impl ComputeSighash for Segwitv0 {
         let psbt_input = &psbt.inputs[input_index];
         let tx_input = &psbt.unsigned_tx.input[input_index];
 
-        let sighash = psbt_input
+        let sighash_type = psbt_input
             .sighash_type
             .unwrap_or_else(|| EcdsaSighashType::All.into())
             .ecdsa_hash_ty()
@@ -953,40 +951,39 @@ impl ComputeSighash for Segwitv0 {
         };
         let value = utxo.value;
 
-        let script = match psbt_input.witness_script {
-            Some(ref witness_script) => witness_script.clone(),
+        let mut sighasher = sighash::SighashCache::new(&psbt.unsigned_tx);
+
+        let sighash = match psbt_input.witness_script {
+            Some(ref witness_script) => {
+                sighasher.p2wsh_signature_hash(input_index, witness_script, value, sighash_type)?
+            }
             None => {
-                if utxo.script_pubkey.is_v0_p2wpkh() {
-                    utxo.script_pubkey
-                        .p2wpkh_script_code()
-                        .expect("We check above that the spk is a p2wpkh")
+                if utxo.script_pubkey.is_p2wpkh() {
+                    sighasher.p2wpkh_signature_hash(
+                        input_index,
+                        &utxo.script_pubkey,
+                        value,
+                        sighash_type,
+                    )?
                 } else if psbt_input
                     .redeem_script
                     .as_ref()
-                    .map(|s| s.is_v0_p2wpkh())
+                    .map(|s| s.is_p2wpkh())
                     .unwrap_or(false)
                 {
-                    psbt_input
-                        .redeem_script
-                        .as_ref()
-                        .unwrap()
-                        .p2wpkh_script_code()
-                        .expect("We check above that the spk is a p2wpkh")
+                    let script_pubkey = psbt_input.redeem_script.as_ref().unwrap();
+                    sighasher.p2wpkh_signature_hash(
+                        input_index,
+                        script_pubkey,
+                        value,
+                        sighash_type,
+                    )?
                 } else {
                     return Err(SignerError::MissingWitnessScript);
                 }
             }
         };
-
-        Ok((
-            sighash::SighashCache::new(&psbt.unsigned_tx).segwit_signature_hash(
-                input_index,
-                &script,
-                value,
-                sighash,
-            )?,
-            sighash,
-        ))
+        Ok((sighash, sighash_type))
     }
 }
 
@@ -996,7 +993,7 @@ impl ComputeSighash for Tap {
     type SighashType = TapSighashType;
 
     fn sighash(
-        psbt: &psbt::PartiallySignedTransaction,
+        psbt: &Psbt,
         input_index: usize,
         extra: Self::Extra,
     ) -> Result<(Self::Sighash, TapSighashType), SignerError> {
@@ -1167,7 +1164,7 @@ mod signers_container_tests {
     impl TransactionSigner for DummySigner {
         fn sign_transaction(
             &self,
-            _psbt: &mut psbt::PartiallySignedTransaction,
+            _psbt: &mut Psbt,
             _sign_options: &SignOptions,
             _secp: &SecpCtx,
         ) -> Result<(), SignerError> {
@@ -1185,8 +1182,8 @@ mod signers_container_tests {
     ) -> (DescriptorKey<Ctx>, DescriptorKey<Ctx>, Fingerprint) {
         let secp: Secp256k1<All> = Secp256k1::new();
         let path = bip32::DerivationPath::from_str(PATH).unwrap();
-        let tprv = bip32::ExtendedPrivKey::from_str(tprv).unwrap();
-        let tpub = bip32::ExtendedPubKey::from_priv(&secp, &tprv);
+        let tprv = bip32::Xpriv::from_str(tprv).unwrap();
+        let tpub = bip32::Xpub::from_priv(&secp, &tprv);
         let fingerprint = tprv.fingerprint(&secp);
         let prvkey = (tprv, path.clone()).into_descriptor_key().unwrap();
         let pubkey = (tpub, path).into_descriptor_key().unwrap();

crates/bdk/src/wallet/tx_builder.rs

@@ -20,7 +20,7 @@
 //! # use bdk::wallet::ChangeSet;
 //! # use bdk::wallet::error::CreateTxError;
 //! # use bdk::wallet::tx_builder::CreateTx;
-//! # use bdk_chain::PersistBackend;
+//! # use bdk_persist::PersistBackend;
 //! # use anyhow::Error;
 //! # let to_address = Address::from_str("2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt").unwrap().assume_checked();
 //! # let mut wallet = doctest_wallet!();
@@ -29,9 +29,9 @@
 //!
 //! tx_builder
 //!     // Create a transaction with one output to `to_address` of 50_000 satoshi
-//!     .add_recipient(to_address.script_pubkey(), 50_000)
+//!     .add_recipient(to_address.script_pubkey(), Amount::from_sat(50_000))
 //!     // With a custom fee rate of 5.0 satoshi/vbyte
-//!     .fee_rate(bdk::FeeRate::from_sat_per_vb(5.0))
+//!     .fee_rate(FeeRate::from_sat_per_vb(5).expect("valid feerate"))
 //!     // Only spend non-change outputs
 //!     .do_not_spend_change()
 //!     // Turn on RBF signaling
@@ -40,22 +40,19 @@
 //! # Ok::<(), anyhow::Error>(())
 //! ```
 
-use crate::collections::BTreeMap;
-use crate::collections::HashSet;
 use alloc::{boxed::Box, rc::Rc, string::String, vec::Vec};
-use bdk_chain::PersistBackend;
 use core::cell::RefCell;
 use core::fmt;
 use core::marker::PhantomData;
 
-use bitcoin::psbt::{self, PartiallySignedTransaction as Psbt};
-use bitcoin::{absolute, script::PushBytes, OutPoint, ScriptBuf, Sequence, Transaction, Txid};
+use bitcoin::psbt::{self, Psbt};
+use bitcoin::script::PushBytes;
+use bitcoin::{absolute, Amount, FeeRate, OutPoint, ScriptBuf, Sequence, Transaction, Txid};
 
 use super::coin_selection::{CoinSelectionAlgorithm, DefaultCoinSelectionAlgorithm};
-use super::ChangeSet;
-use crate::types::{FeeRate, KeychainKind, LocalOutput, WeightedUtxo};
-use crate::wallet::CreateTxError;
-use crate::{Utxo, Wallet};
+use super::{CreateTxError, Wallet};
+use crate::collections::{BTreeMap, HashSet};
+use crate::{KeychainKind, LocalOutput, Utxo, WeightedUtxo};
 
 /// Context in which the [`TxBuilder`] is valid
 pub trait TxBuilderContext: core::fmt::Debug + Default + Clone {}
@@ -87,7 +84,7 @@ impl TxBuilderContext for BumpFee {}
 /// # use core::str::FromStr;
 /// # use bdk::wallet::ChangeSet;
 /// # use bdk::wallet::error::CreateTxError;
-/// # use bdk_chain::PersistBackend;
+/// # use bdk_persist::PersistBackend;
 /// # use anyhow::Error;
 /// # let mut wallet = doctest_wallet!();
 /// # let addr1 = Address::from_str("2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt").unwrap().assume_checked();
@@ -97,8 +94,8 @@ impl TxBuilderContext for BumpFee {}
 ///     let mut builder = wallet.build_tx();
 ///     builder
 ///         .ordering(TxOrdering::Untouched)
-///         .add_recipient(addr1.script_pubkey(), 50_000)
-///         .add_recipient(addr2.script_pubkey(), 50_000);
+///         .add_recipient(addr1.script_pubkey(), Amount::from_sat(50_000))
+///         .add_recipient(addr2.script_pubkey(), Amount::from_sat(50_000));
 ///     builder.finish()?
 /// };
 ///
@@ -107,7 +104,7 @@ impl TxBuilderContext for BumpFee {}
 ///     let mut builder = wallet.build_tx();
 ///     builder.ordering(TxOrdering::Untouched);
 ///     for addr in &[addr1, addr2] {
-///         builder.add_recipient(addr.script_pubkey(), 50_000);
+///         builder.add_recipient(addr.script_pubkey(), Amount::from_sat(50_000));
 ///     }
 ///     builder.finish()?
 /// };
@@ -126,8 +123,8 @@ impl TxBuilderContext for BumpFee {}
 /// [`finish`]: Self::finish
 /// [`coin_selection`]: Self::coin_selection
 #[derive(Debug)]
-pub struct TxBuilder<'a, D, Cs, Ctx> {
-    pub(crate) wallet: Rc<RefCell<&'a mut Wallet<D>>>,
+pub struct TxBuilder<'a, Cs, Ctx> {
+    pub(crate) wallet: Rc<RefCell<&'a mut Wallet>>,
     pub(crate) params: TxParams,
     pub(crate) coin_selection: Cs,
     pub(crate) phantom: PhantomData<Ctx>,
@@ -163,7 +160,7 @@ pub(crate) struct TxParams {
 #[derive(Clone, Copy, Debug)]
 pub(crate) struct PreviousFee {
     pub absolute: u64,
-    pub rate: f32,
+    pub rate: FeeRate,
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -174,11 +171,11 @@ pub(crate) enum FeePolicy {
 
 impl Default for FeePolicy {
     fn default() -> Self {
-        FeePolicy::FeeRate(FeeRate::default_min_relay_fee())
+        FeePolicy::FeeRate(FeeRate::BROADCAST_MIN)
     }
 }
 
-impl<'a, D, Cs: Clone, Ctx> Clone for TxBuilder<'a, D, Cs, Ctx> {
+impl<'a, Cs: Clone, Ctx> Clone for TxBuilder<'a, Cs, Ctx> {
     fn clone(&self) -> Self {
         TxBuilder {
             wallet: self.wallet.clone(),
@@ -190,15 +187,13 @@ impl<'a, D, Cs: Clone, Ctx> Clone for TxBuilder<'a, D, Cs, Ctx> {
 }
 
 // methods supported by both contexts, for any CoinSelectionAlgorithm
-impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D, Cs, Ctx> {
-    /// Set a custom fee rate
-    /// The fee_rate method sets the mining fee paid by the transaction as a rate on its size.
-    /// This means that the total fee paid is equal to this rate * size of the transaction in virtual Bytes (vB) or Weight Unit (wu).
-    /// This rate is internally expressed in satoshis-per-virtual-bytes (sats/vB) using FeeRate::from_sat_per_vb, but can also be set by:
-    /// * sats/kvB (1000 sats/kvB == 1 sats/vB) using FeeRate::from_sat_per_kvb
-    /// * btc/kvB (0.00001000 btc/kvB == 1 sats/vB) using FeeRate::from_btc_per_kvb
-    /// * sats/kwu (250 sats/kwu == 1 sats/vB) using FeeRate::from_sat_per_kwu
-    /// Default is 1 sat/vB (see min_relay_fee)
+impl<'a, Cs, Ctx> TxBuilder<'a, Cs, Ctx> {
+    /// Set a custom fee rate.
+    ///
+    /// This method sets the mining fee paid by the transaction as a rate on its size.
+    /// This means that the total fee paid is equal to `fee_rate` times the size
+    /// of the transaction. Default is 1 sat/vB in accordance with Bitcoin Core's default
+    /// relay policy.
     ///
     /// Note that this is really a minimum feerate -- it's possible to
     /// overshoot it slightly since adding a change output to drain the remaining
@@ -279,7 +274,7 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
     ///
     /// let builder = wallet
     ///     .build_tx()
-    ///     .add_recipient(to_address.script_pubkey(), 50_000)
+    ///     .add_recipient(to_address.script_pubkey(), Amount::from_sat(50_000))
     ///     .policy_path(path, KeychainKind::External);
     ///
     /// # Ok::<(), anyhow::Error>(())
@@ -318,8 +313,7 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
 
             for utxo in utxos {
                 let descriptor = wallet.get_descriptor_for_keychain(utxo.keychain);
-                #[allow(deprecated)]
-                let satisfaction_weight = descriptor.max_satisfaction_weight().unwrap();
+                let satisfaction_weight = descriptor.max_weight_to_satisfy().unwrap();
                 self.params.utxos.push(WeightedUtxo {
                     satisfaction_weight,
                     utxo: Utxo::Local(utxo),
@@ -360,9 +354,9 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
     /// causing you to pay a fee that is too high. The party who is broadcasting the transaction can
     /// of course check the real input weight matches the expected weight prior to broadcasting.
     ///
-    /// To guarantee the `satisfaction_weight` is correct, you can require the party providing the
+    /// To guarantee the `max_weight_to_satisfy` is correct, you can require the party providing the
     /// `psbt_input` provide a miniscript descriptor for the input so you can check it against the
-    /// `script_pubkey` and then ask it for the [`max_satisfaction_weight`].
+    /// `script_pubkey` and then ask it for the [`max_weight_to_satisfy`].
     ///
     /// This is an **EXPERIMENTAL** feature, API and other major changes are expected.
     ///
@@ -383,12 +377,28 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
     ///
     /// [`only_witness_utxo`]: Self::only_witness_utxo
     /// [`finish`]: Self::finish
-    /// [`max_satisfaction_weight`]: miniscript::Descriptor::max_satisfaction_weight
+    /// [`max_weight_to_satisfy`]: miniscript::Descriptor::max_weight_to_satisfy
     pub fn add_foreign_utxo(
         &mut self,
         outpoint: OutPoint,
         psbt_input: psbt::Input,
         satisfaction_weight: usize,
+    ) -> Result<&mut Self, AddForeignUtxoError> {
+        self.add_foreign_utxo_with_sequence(
+            outpoint,
+            psbt_input,
+            satisfaction_weight,
+            Sequence::MAX,
+        )
+    }
+
+    /// Same as [add_foreign_utxo](TxBuilder::add_foreign_utxo) but allows to set the nSequence value.
+    pub fn add_foreign_utxo_with_sequence(
+        &mut self,
+        outpoint: OutPoint,
+        psbt_input: psbt::Input,
+        satisfaction_weight: usize,
+        sequence: Sequence,
     ) -> Result<&mut Self, AddForeignUtxoError> {
         if psbt_input.witness_utxo.is_none() {
             match psbt_input.non_witness_utxo.as_ref() {
@@ -413,6 +423,7 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
             satisfaction_weight,
             utxo: Utxo::Foreign {
                 outpoint,
+                sequence: Some(sequence),
                 psbt_input: Box::new(psbt_input),
             },
         });
@@ -548,7 +559,7 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
     pub fn coin_selection<P: CoinSelectionAlgorithm>(
         self,
         coin_selection: P,
-    ) -> TxBuilder<'a, D, P, Ctx> {
+    ) -> TxBuilder<'a, P, Ctx> {
         TxBuilder {
             wallet: self.wallet,
             params: self.params,
@@ -557,20 +568,6 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
         }
     }
 
-    /// Finish building the transaction.
-    ///
-    /// Returns a new [`Psbt`] per [`BIP174`].
-    ///
-    /// [`BIP174`]: https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki
-    pub fn finish(self) -> Result<Psbt, CreateTxError<D::WriteError>>
-    where
-        D: PersistBackend<ChangeSet>,
-    {
-        self.wallet
-            .borrow_mut()
-            .create_tx(self.coin_selection, self.params)
-    }
-
     /// Enable signaling RBF
     ///
     /// This will use the default nSequence value of `0xFFFFFFFD`.
@@ -617,6 +614,19 @@ impl<'a, D, Cs: CoinSelectionAlgorithm, Ctx: TxBuilderContext> TxBuilder<'a, D,
     }
 }
 
+impl<'a, Cs: CoinSelectionAlgorithm, Ctx> TxBuilder<'a, Cs, Ctx> {
+    /// Finish building the transaction.
+    ///
+    /// Returns a new [`Psbt`] per [`BIP174`].
+    ///
+    /// [`BIP174`]: https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki
+    pub fn finish(self) -> Result<Psbt, CreateTxError> {
+        self.wallet
+            .borrow_mut()
+            .create_tx(self.coin_selection, self.params)
+    }
+}
+
 #[derive(Debug)]
 /// Error returned from [`TxBuilder::add_utxo`] and [`TxBuilder::add_utxos`]
 pub enum AddUtxoError {
@@ -701,23 +711,28 @@ impl fmt::Display for AllowShrinkingError {
 #[cfg(feature = "std")]
 impl std::error::Error for AllowShrinkingError {}
 
-impl<'a, D, Cs: CoinSelectionAlgorithm> TxBuilder<'a, D, Cs, CreateTx> {
+impl<'a, Cs: CoinSelectionAlgorithm> TxBuilder<'a, Cs, CreateTx> {
     /// Replace the recipients already added with a new list
-    pub fn set_recipients(&mut self, recipients: Vec<(ScriptBuf, u64)>) -> &mut Self {
-        self.params.recipients = recipients;
+    pub fn set_recipients(&mut self, recipients: Vec<(ScriptBuf, Amount)>) -> &mut Self {
+        self.params.recipients = recipients
+            .into_iter()
+            .map(|(script, amount)| (script, amount.to_sat()))
+            .collect();
         self
     }
 
     /// Add a recipient to the internal list
-    pub fn add_recipient(&mut self, script_pubkey: ScriptBuf, amount: u64) -> &mut Self {
-        self.params.recipients.push((script_pubkey, amount));
+    pub fn add_recipient(&mut self, script_pubkey: ScriptBuf, amount: Amount) -> &mut Self {
+        self.params
+            .recipients
+            .push((script_pubkey, amount.to_sat()));
         self
     }
 
     /// Add data as an output, using OP_RETURN
     pub fn add_data<T: AsRef<PushBytes>>(&mut self, data: &T) -> &mut Self {
         let script = ScriptBuf::new_op_return(data);
-        self.add_recipient(script, 0u64);
+        self.add_recipient(script, Amount::ZERO);
         self
     }
 
@@ -748,7 +763,7 @@ impl<'a, D, Cs: CoinSelectionAlgorithm> TxBuilder<'a, D, Cs, CreateTx> {
     /// # use bdk::wallet::ChangeSet;
     /// # use bdk::wallet::error::CreateTxError;
     /// # use bdk::wallet::tx_builder::CreateTx;
-    /// # use bdk_chain::PersistBackend;
+    /// # use bdk_persist::PersistBackend;
     /// # use anyhow::Error;
     /// # let to_address =
     /// Address::from_str("2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt")
@@ -762,7 +777,7 @@ impl<'a, D, Cs: CoinSelectionAlgorithm> TxBuilder<'a, D, Cs, CreateTx> {
     ///     .drain_wallet()
     ///     // Send the excess (which is all the coins minus the fee) to this address.
     ///     .drain_to(to_address.script_pubkey())
-    ///     .fee_rate(bdk::FeeRate::from_sat_per_vb(5.0))
+    ///     .fee_rate(FeeRate::from_sat_per_vb(5).expect("valid feerate"))
     ///     .enable_rbf();
     /// let psbt = tx_builder.finish()?;
     /// # Ok::<(), anyhow::Error>(())
@@ -779,7 +794,7 @@ impl<'a, D, Cs: CoinSelectionAlgorithm> TxBuilder<'a, D, Cs, CreateTx> {
 }
 
 // methods supported only by bump_fee
-impl<'a, D> TxBuilder<'a, D, DefaultCoinSelectionAlgorithm, BumpFee> {
+impl<'a> TxBuilder<'a, DefaultCoinSelectionAlgorithm, BumpFee> {
     /// Explicitly tells the wallet that it is allowed to reduce the amount of the output matching this
     /// `script_pubkey` in order to bump the transaction fee. Without specifying this the wallet
     /// will attempt to find a change output to shrink instead.
@@ -811,9 +826,10 @@ impl<'a, D> TxBuilder<'a, D, DefaultCoinSelectionAlgorithm, BumpFee> {
 }
 
 /// Ordering of the transaction's inputs and outputs
-#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Clone, Copy)]
+#[derive(Default, Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Clone, Copy)]
 pub enum TxOrdering {
     /// Randomized (default)
+    #[default]
     Shuffle,
     /// Unchanged
     Untouched,
@@ -821,12 +837,6 @@ pub enum TxOrdering {
     Bip69Lexicographic,
 }
 
-impl Default for TxOrdering {
-    fn default() -> Self {
-        TxOrdering::Shuffle
-    }
-}
-
 impl TxOrdering {
     /// Sort transaction inputs and outputs by [`TxOrdering`] variant
     pub fn sort_tx(&self, tx: &mut Transaction) {
@@ -880,9 +890,10 @@ impl RbfValue {
 }
 
 /// Policy regarding the use of change outputs when creating a transaction
-#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Clone, Copy)]
+#[derive(Default, Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Clone, Copy)]
 pub enum ChangeSpendPolicy {
     /// Use both change and non-change outputs (default)
+    #[default]
     ChangeAllowed,
     /// Only use change outputs (see [`TxBuilder::only_spend_change`])
     OnlyChange,
@@ -890,12 +901,6 @@ pub enum ChangeSpendPolicy {
     ChangeForbidden,
 }
 
-impl Default for ChangeSpendPolicy {
-    fn default() -> Self {
-        ChangeSpendPolicy::ChangeAllowed
-    }
-}
-
 impl ChangeSpendPolicy {
     pub(crate) fn is_satisfied_by(&self, utxo: &LocalOutput) -> bool {
         match self {
@@ -923,7 +928,8 @@ mod test {
 
     use bdk_chain::ConfirmationTime;
     use bitcoin::consensus::deserialize;
-    use bitcoin::hashes::hex::FromHex;
+    use bitcoin::hex::FromHex;
+    use bitcoin::TxOut;
 
     use super::*;
 
@@ -994,7 +1000,7 @@ mod test {
             .unwrap()
         );
 
-        assert_eq!(tx.output[0].value, 800);
+        assert_eq!(tx.output[0].value.to_sat(), 800);
         assert_eq!(tx.output[1].script_pubkey, ScriptBuf::from(vec![0xAA]));
         assert_eq!(
             tx.output[2].script_pubkey,
@@ -1011,7 +1017,7 @@ mod test {
                     txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(),
                     vout: 0,
                 },
-                txout: Default::default(),
+                txout: TxOut::NULL,
                 keychain: KeychainKind::External,
                 is_spent: false,
                 confirmation_time: ConfirmationTime::Unconfirmed { last_seen: 0 },
@@ -1022,7 +1028,7 @@ mod test {
                     txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(),
                     vout: 1,
                 },
-                txout: Default::default(),
+                txout: TxOut::NULL,
                 keychain: KeychainKind::Internal,
                 is_spent: false,
                 confirmation_time: ConfirmationTime::Confirmed {

crates/bdk/src/wallet/utils.rs

@@ -138,7 +138,7 @@ mod test {
             .require_network(Network::Bitcoin)
             .unwrap()
             .script_pubkey();
-        assert!(script_p2wpkh.is_v0_p2wpkh());
+        assert!(script_p2wpkh.is_p2wpkh());
         assert!(293.is_dust(&script_p2wpkh));
         assert!(!294.is_dust(&script_p2wpkh));
     }

crates/bdk/tests/common.rs

@@ -1,10 +1,13 @@
 #![allow(unused)]
 
-use bdk::{wallet::AddressIndex, KeychainKind, LocalOutput, Wallet};
+use bdk::{KeychainKind, LocalOutput, Wallet};
 use bdk_chain::indexed_tx_graph::Indexer;
 use bdk_chain::{BlockId, ConfirmationTime};
 use bitcoin::hashes::Hash;
-use bitcoin::{Address, BlockHash, Network, OutPoint, Transaction, TxIn, TxOut, Txid};
+use bitcoin::{
+    transaction, Address, Amount, BlockHash, FeeRate, Network, OutPoint, Transaction, TxIn, TxOut,
+    Txid,
+};
 use std::str::FromStr;
 
 // Return a fake wallet that appears to be funded for testing.
@@ -17,14 +20,14 @@ pub fn get_funded_wallet_with_change(
     change: Option<&str>,
 ) -> (Wallet, bitcoin::Txid) {
     let mut wallet = Wallet::new_no_persist(descriptor, change, Network::Regtest).unwrap();
-    let change_address = wallet.get_address(AddressIndex::New).address;
+    let change_address = wallet.peek_address(KeychainKind::External, 0).address;
     let sendto_address = Address::from_str("bcrt1q3qtze4ys45tgdvguj66zrk4fu6hq3a3v9pfly5")
         .expect("address")
         .require_network(Network::Regtest)
         .unwrap();
 
     let tx0 = Transaction {
-        version: 1,
+        version: transaction::Version::ONE,
         lock_time: bitcoin::absolute::LockTime::ZERO,
         input: vec![TxIn {
             previous_output: OutPoint {
@@ -36,13 +39,13 @@ pub fn get_funded_wallet_with_change(
             witness: Default::default(),
         }],
         output: vec![TxOut {
-            value: 76_000,
+            value: Amount::from_sat(76_000),
             script_pubkey: change_address.script_pubkey(),
         }],
     };
 
     let tx1 = Transaction {
-        version: 1,
+        version: transaction::Version::ONE,
         lock_time: bitcoin::absolute::LockTime::ZERO,
         input: vec![TxIn {
             previous_output: OutPoint {
@@ -55,11 +58,11 @@ pub fn get_funded_wallet_with_change(
         }],
         output: vec![
             TxOut {
-                value: 50_000,
+                value: Amount::from_sat(50_000),
                 script_pubkey: change_address.script_pubkey(),
             },
             TxOut {
-                value: 25_000,
+                value: Amount::from_sat(25_000),
                 script_pubkey: sendto_address.script_pubkey(),
             },
         ],
@@ -154,3 +157,16 @@ pub fn get_test_tr_with_taptree_xprv() -> &'static str {
 pub fn get_test_tr_dup_keys() -> &'static str {
     "tr(cNJmN3fH9DDbDt131fQNkVakkpzawJBSeybCUNmP1BovpmGQ45xG,{pk(8aee2b8120a5f157f1223f72b5e62b825831a27a9fdf427db7cc697494d4a642),pk(8aee2b8120a5f157f1223f72b5e62b825831a27a9fdf427db7cc697494d4a642)})"
 }
+
+/// Construct a new [`FeeRate`] from the given raw `sat_vb` feerate. This is
+/// useful in cases where we want to create a feerate from a `f64`, as the
+/// traditional [`FeeRate::from_sat_per_vb`] method will only accept an integer.
+///
+/// **Note** this 'quick and dirty' conversion should only be used when the input
+/// parameter has units of `satoshis/vbyte` **AND** is not expected to overflow,
+/// or else the resulting value will be inaccurate.
+pub fn feerate_unchecked(sat_vb: f64) -> FeeRate {
+    // 1 sat_vb / 4wu_vb * 1000kwu_wu = 250 sat_kwu
+    let sat_kwu = (sat_vb * 250.0).ceil() as u64;
+    FeeRate::from_sat_per_kwu(sat_kwu)
+}

crates/bdk/tests/psbt.rs

@@ -1,8 +1,5 @@
-use bdk::bitcoin::TxIn;
-use bdk::wallet::AddressIndex;
-use bdk::wallet::AddressIndex::New;
-use bdk::{psbt, FeeRate, SignOptions};
-use bitcoin::psbt::PartiallySignedTransaction as Psbt;
+use bdk::bitcoin::{Amount, FeeRate, Psbt, TxIn};
+use bdk::{psbt, KeychainKind, SignOptions};
 use core::str::FromStr;
 mod common;
 use common::*;
@@ -15,9 +12,9 @@ const PSBT_STR: &str = "cHNidP8BAKACAAAAAqsJSaCMWvfEm4IS9Bfi8Vqz9cM9zxU4IagTn4d6
 fn test_psbt_malformed_psbt_input_legacy() {
     let psbt_bip = Psbt::from_str(PSBT_STR).unwrap();
     let (mut wallet, _) = get_funded_wallet(get_test_wpkh());
-    let send_to = wallet.get_address(AddressIndex::New);
+    let send_to = wallet.peek_address(KeychainKind::External, 0);
     let mut builder = wallet.build_tx();
-    builder.add_recipient(send_to.script_pubkey(), 10_000);
+    builder.add_recipient(send_to.script_pubkey(), Amount::from_sat(10_000));
     let mut psbt = builder.finish().unwrap();
     psbt.inputs.push(psbt_bip.inputs[0].clone());
     let options = SignOptions {
@@ -32,9 +29,9 @@ fn test_psbt_malformed_psbt_input_legacy() {
 fn test_psbt_malformed_psbt_input_segwit() {
     let psbt_bip = Psbt::from_str(PSBT_STR).unwrap();
     let (mut wallet, _) = get_funded_wallet(get_test_wpkh());
-    let send_to = wallet.get_address(AddressIndex::New);
+    let send_to = wallet.peek_address(KeychainKind::External, 0);
     let mut builder = wallet.build_tx();
-    builder.add_recipient(send_to.script_pubkey(), 10_000);
+    builder.add_recipient(send_to.script_pubkey(), Amount::from_sat(10_000));
     let mut psbt = builder.finish().unwrap();
     psbt.inputs.push(psbt_bip.inputs[1].clone());
     let options = SignOptions {
@@ -48,9 +45,9 @@ fn test_psbt_malformed_psbt_input_segwit() {
 #[should_panic(expected = "InputIndexOutOfRange")]
 fn test_psbt_malformed_tx_input() {
     let (mut wallet, _) = get_funded_wallet(get_test_wpkh());
-    let send_to = wallet.get_address(AddressIndex::New);
+    let send_to = wallet.peek_address(KeychainKind::External, 0);
     let mut builder = wallet.build_tx();
-    builder.add_recipient(send_to.script_pubkey(), 10_000);
+    builder.add_recipient(send_to.script_pubkey(), Amount::from_sat(10_000));
     let mut psbt = builder.finish().unwrap();
     psbt.unsigned_tx.input.push(TxIn::default());
     let options = SignOptions {
@@ -64,9 +61,9 @@ fn test_psbt_malformed_tx_input() {
 fn test_psbt_sign_with_finalized() {
     let psbt_bip = Psbt::from_str(PSBT_STR).unwrap();
     let (mut wallet, _) = get_funded_wallet(get_test_wpkh());
-    let send_to = wallet.get_address(AddressIndex::New);
+    let send_to = wallet.peek_address(KeychainKind::External, 0);
     let mut builder = wallet.build_tx();
-    builder.add_recipient(send_to.script_pubkey(), 10_000);
+    builder.add_recipient(send_to.script_pubkey(), Amount::from_sat(10_000));
     let mut psbt = builder.finish().unwrap();
 
     // add a finalized input
@@ -82,13 +79,13 @@ fn test_psbt_sign_with_finalized() {
 fn test_psbt_fee_rate_with_witness_utxo() {
     use psbt::PsbtUtils;
 
-    let expected_fee_rate = 1.2345;
+    let expected_fee_rate = FeeRate::from_sat_per_kwu(310);
 
     let (mut wallet, _) = get_funded_wallet("wpkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
-    let addr = wallet.get_address(New);
+    let addr = wallet.peek_address(KeychainKind::External, 0);
     let mut builder = wallet.build_tx();
     builder.drain_to(addr.script_pubkey()).drain_wallet();
-    builder.fee_rate(FeeRate::from_sat_per_vb(expected_fee_rate));
+    builder.fee_rate(expected_fee_rate);
     let mut psbt = builder.finish().unwrap();
     let fee_amount = psbt.fee_amount();
     assert!(fee_amount.is_some());
@@ -99,21 +96,21 @@ fn test_psbt_fee_rate_with_witness_utxo() {
     assert!(finalized);
 
     let finalized_fee_rate = psbt.fee_rate().unwrap();
-    assert!(finalized_fee_rate.as_sat_per_vb() >= expected_fee_rate);
-    assert!(finalized_fee_rate.as_sat_per_vb() < unfinalized_fee_rate.as_sat_per_vb());
+    assert!(finalized_fee_rate >= expected_fee_rate);
+    assert!(finalized_fee_rate < unfinalized_fee_rate);
 }
 
 #[test]
 fn test_psbt_fee_rate_with_nonwitness_utxo() {
     use psbt::PsbtUtils;
 
-    let expected_fee_rate = 1.2345;
+    let expected_fee_rate = FeeRate::from_sat_per_kwu(310);
 
     let (mut wallet, _) = get_funded_wallet("pkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
-    let addr = wallet.get_address(New);
+    let addr = wallet.peek_address(KeychainKind::External, 0);
     let mut builder = wallet.build_tx();
     builder.drain_to(addr.script_pubkey()).drain_wallet();
-    builder.fee_rate(FeeRate::from_sat_per_vb(expected_fee_rate));
+    builder.fee_rate(expected_fee_rate);
     let mut psbt = builder.finish().unwrap();
     let fee_amount = psbt.fee_amount();
     assert!(fee_amount.is_some());
@@ -123,21 +120,21 @@ fn test_psbt_fee_rate_with_nonwitness_utxo() {
     assert!(finalized);
 
     let finalized_fee_rate = psbt.fee_rate().unwrap();
-    assert!(finalized_fee_rate.as_sat_per_vb() >= expected_fee_rate);
-    assert!(finalized_fee_rate.as_sat_per_vb() < unfinalized_fee_rate.as_sat_per_vb());
+    assert!(finalized_fee_rate >= expected_fee_rate);
+    assert!(finalized_fee_rate < unfinalized_fee_rate);
 }
 
 #[test]
 fn test_psbt_fee_rate_with_missing_txout() {
     use psbt::PsbtUtils;
 
-    let expected_fee_rate = 1.2345;
+    let expected_fee_rate = FeeRate::from_sat_per_kwu(310);
 
     let (mut wpkh_wallet,  _) = get_funded_wallet("wpkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
-    let addr = wpkh_wallet.get_address(New);
+    let addr = wpkh_wallet.peek_address(KeychainKind::External, 0);
     let mut builder = wpkh_wallet.build_tx();
     builder.drain_to(addr.script_pubkey()).drain_wallet();
-    builder.fee_rate(FeeRate::from_sat_per_vb(expected_fee_rate));
+    builder.fee_rate(expected_fee_rate);
     let mut wpkh_psbt = builder.finish().unwrap();
 
     wpkh_psbt.inputs[0].witness_utxo = None;
@@ -146,10 +143,10 @@ fn test_psbt_fee_rate_with_missing_txout() {
     assert!(wpkh_psbt.fee_rate().is_none());
 
     let (mut pkh_wallet,  _) = get_funded_wallet("pkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
-    let addr = pkh_wallet.get_address(New);
+    let addr = pkh_wallet.peek_address(KeychainKind::External, 0);
     let mut builder = pkh_wallet.build_tx();
     builder.drain_to(addr.script_pubkey()).drain_wallet();
-    builder.fee_rate(FeeRate::from_sat_per_vb(expected_fee_rate));
+    builder.fee_rate(expected_fee_rate);
     let mut pkh_psbt = builder.finish().unwrap();
 
     pkh_psbt.inputs[0].non_witness_utxo = None;
@@ -161,16 +158,26 @@ fn test_psbt_fee_rate_with_missing_txout() {
 fn test_psbt_multiple_internalkey_signers() {
     use bdk::signer::{SignerContext, SignerOrdering, SignerWrapper};
     use bdk::KeychainKind;
-    use bitcoin::{secp256k1::Secp256k1, PrivateKey};
-    use miniscript::psbt::PsbtExt;
+    use bitcoin::key::TapTweak;
+    use bitcoin::secp256k1::{schnorr, Keypair, Message, Secp256k1, XOnlyPublicKey};
+    use bitcoin::sighash::{Prevouts, SighashCache, TapSighashType};
+    use bitcoin::{PrivateKey, TxOut};
     use std::sync::Arc;
 
     let secp = Secp256k1::new();
-    let (mut wallet, _) = get_funded_wallet(get_test_tr_single_sig());
-    let send_to = wallet.get_address(AddressIndex::New);
+    let wif = "cNJmN3fH9DDbDt131fQNkVakkpzawJBSeybCUNmP1BovpmGQ45xG";
+    let desc = format!("tr({})", wif);
+    let prv = PrivateKey::from_wif(wif).unwrap();
+    let keypair = Keypair::from_secret_key(&secp, &prv.inner);
+
+    let (mut wallet, _) = get_funded_wallet(&desc);
+    let to_spend = wallet.get_balance().total();
+    let send_to = wallet.peek_address(KeychainKind::External, 0);
     let mut builder = wallet.build_tx();
-    builder.add_recipient(send_to.script_pubkey(), 10_000);
+    builder.drain_to(send_to.script_pubkey()).drain_wallet();
     let mut psbt = builder.finish().unwrap();
+    let unsigned_tx = psbt.unsigned_tx.clone();
+
     // Adds a signer for the wrong internal key, bdk should not use this key to sign
     wallet.add_signer(
         KeychainKind::External,
@@ -183,10 +190,32 @@ fn test_psbt_multiple_internalkey_signers() {
             },
         )),
     );
-    let _ = wallet.sign(&mut psbt, SignOptions::default()).unwrap();
-    // Checks that we signed using the right key
-    assert!(
-        psbt.finalize_mut(&secp).is_ok(),
-        "The wrong internal key was used"
-    );
+    let finalized = wallet.sign(&mut psbt, SignOptions::default()).unwrap();
+    assert!(finalized);
+
+    // To verify, we need the signature, message, and pubkey
+    let witness = psbt.inputs[0].final_script_witness.as_ref().unwrap();
+    assert!(!witness.is_empty());
+    let signature = schnorr::Signature::from_slice(witness.iter().next().unwrap()).unwrap();
+
+    // the prevout we're spending
+    let prevouts = &[TxOut {
+        script_pubkey: send_to.script_pubkey(),
+        value: to_spend,
+    }];
+    let prevouts = Prevouts::All(prevouts);
+    let input_index = 0;
+    let mut sighash_cache = SighashCache::new(unsigned_tx);
+    let sighash = sighash_cache
+        .taproot_key_spend_signature_hash(input_index, &prevouts, TapSighashType::Default)
+        .unwrap();
+    let message = Message::from(sighash);
+
+    // add tweak. this was taken from `signer::sign_psbt_schnorr`
+    let keypair = keypair.tap_tweak(&secp, None).to_inner();
+    let (xonlykey, _parity) = XOnlyPublicKey::from_keypair(&keypair);
+
+    // Must verify if we used the correct key to sign
+    let verify_res = secp.verify_schnorr(&signature, &message, &xonlykey);
+    assert!(verify_res.is_ok(), "The wrong internal key was used");
 }

crates/bitcoind_rpc/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "bdk_bitcoind_rpc"
-version = "0.1.0"
+version = "0.10.0"
 edition = "2021"
-rust-version = "1.57"
+rust-version = "1.63"
 homepage = "https://bitcoindevkit.org"
 repository = "https://github.com/bitcoindevkit/bdk"
 documentation = "https://docs.rs/bdk_bitcoind_rpc"
@@ -14,13 +14,12 @@ readme = "README.md"
 
 [dependencies]
 # For no-std, remember to enable the bitcoin/no-std feature
-bitcoin = { version = "0.30", default-features = false }
-bitcoincore-rpc = { version = "0.17" }
-bdk_chain = { path = "../chain", version = "0.6", default-features = false }
+bitcoin = { version = "0.31", default-features = false }
+bitcoincore-rpc = { version = "0.18" }
+bdk_chain = { path = "../chain", version = "0.14", default-features = false }
 
 [dev-dependencies]
-bitcoind = { version = "0.33", features = ["25_0"] }
-anyhow = { version = "1" }
+bdk_testenv = { path = "../testenv", default_features = false }
 
 [features]
 default = ["std"]

crates/bitcoind_rpc/src/lib.rs

@@ -14,7 +14,7 @@ use bitcoin::{block::Header, Block, BlockHash, Transaction};
 pub use bitcoincore_rpc;
 use bitcoincore_rpc::bitcoincore_rpc_json;
 
-/// A structure that emits data sourced from [`bitcoincore_rpc::Client`].
+/// The [`Emitter`] is used to emit data sourced from [`bitcoincore_rpc::Client`].
 ///
 /// Refer to [module-level documentation] for more.
 ///
@@ -43,11 +43,13 @@ pub struct Emitter<'c, C> {
 }
 
 impl<'c, C: bitcoincore_rpc::RpcApi> Emitter<'c, C> {
-    /// Construct a new [`Emitter`] with the given RPC `client`, `last_cp` and `start_height`.
+    /// Construct a new [`Emitter`].
     ///
-    /// * `last_cp` is the check point used to find the latest block which is still part of the best
-    ///   chain.
-    /// * `start_height` is the block height to start emitting blocks from.
+    /// `last_cp` informs the emitter of the chain we are starting off with. This way, the emitter
+    /// can start emission from a block that connects to the original chain.
+    ///
+    /// `start_height` starts emission from a given height (if there are no conflicts with the
+    /// original chain).
     pub fn new(client: &'c C, last_cp: CheckPoint, start_height: u32) -> Self {
         Self {
             client,
@@ -127,13 +129,58 @@ impl<'c, C: bitcoincore_rpc::RpcApi> Emitter<'c, C> {
     }
 
     /// Emit the next block height and header (if any).
-    pub fn next_header(&mut self) -> Result<Option<(u32, Header)>, bitcoincore_rpc::Error> {
-        poll(self, |hash| self.client.get_block_header(hash))
+    pub fn next_header(&mut self) -> Result<Option<BlockEvent<Header>>, bitcoincore_rpc::Error> {
+        Ok(poll(self, |hash| self.client.get_block_header(hash))?
+            .map(|(checkpoint, block)| BlockEvent { block, checkpoint }))
     }
 
     /// Emit the next block height and block (if any).
-    pub fn next_block(&mut self) -> Result<Option<(u32, Block)>, bitcoincore_rpc::Error> {
-        poll(self, |hash| self.client.get_block(hash))
+    pub fn next_block(&mut self) -> Result<Option<BlockEvent<Block>>, bitcoincore_rpc::Error> {
+        Ok(poll(self, |hash| self.client.get_block(hash))?
+            .map(|(checkpoint, block)| BlockEvent { block, checkpoint }))
+    }
+}
+
+/// A newly emitted block from [`Emitter`].
+#[derive(Debug)]
+pub struct BlockEvent<B> {
+    /// Either a full [`Block`] or [`Header`] of the new block.
+    pub block: B,
+
+    /// The checkpoint of the new block.
+    ///
+    /// A [`CheckPoint`] is a node of a linked list of [`BlockId`]s. This checkpoint is linked to
+    /// all [`BlockId`]s originally passed in [`Emitter::new`] as well as emitted blocks since then.
+    /// These blocks are guaranteed to be of the same chain.
+    ///
+    /// This is important as BDK structures require block-to-apply to be connected with another
+    /// block in the original chain.
+    pub checkpoint: CheckPoint,
+}
+
+impl<B> BlockEvent<B> {
+    /// The block height of this new block.
+    pub fn block_height(&self) -> u32 {
+        self.checkpoint.height()
+    }
+
+    /// The block hash of this new block.
+    pub fn block_hash(&self) -> BlockHash {
+        self.checkpoint.hash()
+    }
+
+    /// The [`BlockId`] of a previous block that this block connects to.
+    ///
+    /// This either returns a [`BlockId`] of a previously emitted block or from the chain we started
+    /// with (passed in as `last_cp` in [`Emitter::new`]).
+    ///
+    /// This value is derived from [`BlockEvent::checkpoint`].
+    pub fn connected_to(&self) -> BlockId {
+        match self.checkpoint.prev() {
+            Some(prev_cp) => prev_cp.block_id(),
+            // there is no previous checkpoint, so just connect with itself
+            None => self.checkpoint.block_id(),
+        }
     }
 }
 
@@ -203,7 +250,7 @@ where
 fn poll<C, V, F>(
     emitter: &mut Emitter<C>,
     get_item: F,
-) -> Result<Option<(u32, V)>, bitcoincore_rpc::Error>
+) -> Result<Option<(CheckPoint, V)>, bitcoincore_rpc::Error>
 where
     C: bitcoincore_rpc::RpcApi,
     F: Fn(&BlockHash) -> Result<V, bitcoincore_rpc::Error>,
@@ -215,13 +262,14 @@ where
                 let hash = res.hash;
                 let item = get_item(&hash)?;
 
-                emitter.last_cp = emitter
+                let new_cp = emitter
                     .last_cp
                     .clone()
                     .push(BlockId { height, hash })
                     .expect("must push");
+                emitter.last_cp = new_cp.clone();
                 emitter.last_block = Some(res);
-                return Ok(Some((height, item)));
+                return Ok(Some((new_cp, item)));
             }
             PollResponse::NoMoreBlocks => {
                 emitter.last_block = None;

crates/bitcoind_rpc/tests/test_emitter.rs

@@ -2,182 +2,14 @@ use std::collections::{BTreeMap, BTreeSet};
 
 use bdk_bitcoind_rpc::Emitter;
 use bdk_chain::{
-    bitcoin::{Address, Amount, BlockHash, Txid},
+    bitcoin::{Address, Amount, Txid},
     keychain::Balance,
-    local_chain::{self, CheckPoint, LocalChain},
+    local_chain::{CheckPoint, LocalChain},
     Append, BlockId, IndexedTxGraph, SpkTxOutIndex,
 };
-use bitcoin::{
-    address::NetworkChecked, block::Header, hash_types::TxMerkleNode, hashes::Hash,
-    secp256k1::rand::random, Block, CompactTarget, OutPoint, ScriptBuf, ScriptHash, Transaction,
-    TxIn, TxOut, WScriptHash,
-};
-use bitcoincore_rpc::{
-    bitcoincore_rpc_json::{GetBlockTemplateModes, GetBlockTemplateRules},
-    RpcApi,
-};
-
-struct TestEnv {
-    #[allow(dead_code)]
-    daemon: bitcoind::BitcoinD,
-    client: bitcoincore_rpc::Client,
-}
-
-impl TestEnv {
-    fn new() -> anyhow::Result<Self> {
-        let daemon = match std::env::var_os("TEST_BITCOIND") {
-            Some(bitcoind_path) => bitcoind::BitcoinD::new(bitcoind_path),
-            None => bitcoind::BitcoinD::from_downloaded(),
-        }?;
-        let client = bitcoincore_rpc::Client::new(
-            &daemon.rpc_url(),
-            bitcoincore_rpc::Auth::CookieFile(daemon.params.cookie_file.clone()),
-        )?;
-        Ok(Self { daemon, client })
-    }
-
-    fn mine_blocks(
-        &self,
-        count: usize,
-        address: Option<Address>,
-    ) -> anyhow::Result<Vec<BlockHash>> {
-        let coinbase_address = match address {
-            Some(address) => address,
-            None => self.client.get_new_address(None, None)?.assume_checked(),
-        };
-        let block_hashes = self
-            .client
-            .generate_to_address(count as _, &coinbase_address)?;
-        Ok(block_hashes)
-    }
-
-    fn mine_empty_block(&self) -> anyhow::Result<(usize, BlockHash)> {
-        let bt = self.client.get_block_template(
-            GetBlockTemplateModes::Template,
-            &[GetBlockTemplateRules::SegWit],
-            &[],
-        )?;
-
-        let txdata = vec![Transaction {
-            version: 1,
-            lock_time: bitcoin::absolute::LockTime::from_height(0)?,
-            input: vec![TxIn {
-                previous_output: bitcoin::OutPoint::default(),
-                script_sig: ScriptBuf::builder()
-                    .push_int(bt.height as _)
-                    // randomn number so that re-mining creates unique block
-                    .push_int(random())
-                    .into_script(),
-                sequence: bitcoin::Sequence::default(),
-                witness: bitcoin::Witness::new(),
-            }],
-            output: vec![TxOut {
-                value: 0,
-                script_pubkey: ScriptBuf::new_p2sh(&ScriptHash::all_zeros()),
-            }],
-        }];
-
-        let bits: [u8; 4] = bt
-            .bits
-            .clone()
-            .try_into()
-            .expect("rpc provided us with invalid bits");
-
-        let mut block = Block {
-            header: Header {
-                version: bitcoin::block::Version::default(),
-                prev_blockhash: bt.previous_block_hash,
-                merkle_root: TxMerkleNode::all_zeros(),
-                time: Ord::max(bt.min_time, std::time::UNIX_EPOCH.elapsed()?.as_secs()) as u32,
-                bits: CompactTarget::from_consensus(u32::from_be_bytes(bits)),
-                nonce: 0,
-            },
-            txdata,
-        };
-
-        block.header.merkle_root = block.compute_merkle_root().expect("must compute");
-
-        for nonce in 0..=u32::MAX {
-            block.header.nonce = nonce;
-            if block.header.target().is_met_by(block.block_hash()) {
-                break;
-            }
-        }
-
-        self.client.submit_block(&block)?;
-        Ok((bt.height as usize, block.block_hash()))
-    }
-
-    fn invalidate_blocks(&self, count: usize) -> anyhow::Result<()> {
-        let mut hash = self.client.get_best_block_hash()?;
-        for _ in 0..count {
-            let prev_hash = self.client.get_block_info(&hash)?.previousblockhash;
-            self.client.invalidate_block(&hash)?;
-            match prev_hash {
-                Some(prev_hash) => hash = prev_hash,
-                None => break,
-            }
-        }
-        Ok(())
-    }
-
-    fn reorg(&self, count: usize) -> anyhow::Result<Vec<BlockHash>> {
-        let start_height = self.client.get_block_count()?;
-        self.invalidate_blocks(count)?;
-
-        let res = self.mine_blocks(count, None);
-        assert_eq!(
-            self.client.get_block_count()?,
-            start_height,
-            "reorg should not result in height change"
-        );
-        res
-    }
-
-    fn reorg_empty_blocks(&self, count: usize) -> anyhow::Result<Vec<(usize, BlockHash)>> {
-        let start_height = self.client.get_block_count()?;
-        self.invalidate_blocks(count)?;
-
-        let res = (0..count)
-            .map(|_| self.mine_empty_block())
-            .collect::<Result<Vec<_>, _>>()?;
-        assert_eq!(
-            self.client.get_block_count()?,
-            start_height,
-            "reorg should not result in height change"
-        );
-        Ok(res)
-    }
-
-    fn send(&self, address: &Address<NetworkChecked>, amount: Amount) -> anyhow::Result<Txid> {
-        let txid = self
-            .client
-            .send_to_address(address, amount, None, None, None, None, None, None)?;
-        Ok(txid)
-    }
-}
-
-fn block_to_chain_update(block: &bitcoin::Block, height: u32) -> local_chain::Update {
-    let this_id = BlockId {
-        height,
-        hash: block.block_hash(),
-    };
-    let tip = if block.header.prev_blockhash == BlockHash::all_zeros() {
-        CheckPoint::new(this_id)
-    } else {
-        CheckPoint::new(BlockId {
-            height: height - 1,
-            hash: block.header.prev_blockhash,
-        })
-        .extend(core::iter::once(this_id))
-        .expect("must construct checkpoint")
-    };
-
-    local_chain::Update {
-        tip,
-        introduce_older_blocks: false,
-    }
-}
+use bdk_testenv::{anyhow, TestEnv};
+use bitcoin::{hashes::Hash, Block, OutPoint, ScriptBuf, WScriptHash};
+use bitcoincore_rpc::RpcApi;
 
 /// Ensure that blocks are emitted in order even after reorg.
 ///
@@ -188,44 +20,53 @@ fn block_to_chain_update(block: &bitcoin::Block, height: u32) -> local_chain::Up
 #[test]
 pub fn test_sync_local_chain() -> anyhow::Result<()> {
     let env = TestEnv::new()?;
-    let (mut local_chain, _) = LocalChain::from_genesis_hash(env.client.get_block_hash(0)?);
-    let mut emitter = Emitter::new(&env.client, local_chain.tip(), 0);
+    let network_tip = env.rpc_client().get_block_count()?;
+    let (mut local_chain, _) = LocalChain::from_genesis_hash(env.rpc_client().get_block_hash(0)?);
+    let mut emitter = Emitter::new(env.rpc_client(), local_chain.tip(), 0);
 
-    // mine some blocks and returned the actual block hashes
+    // Mine some blocks and return the actual block hashes.
+    // Because initializing `ElectrsD` already mines some blocks, we must include those too when
+    // returning block hashes.
     let exp_hashes = {
-        let mut hashes = vec![env.client.get_block_hash(0)?]; // include genesis block
-        hashes.extend(env.mine_blocks(101, None)?);
+        let mut hashes = (0..=network_tip)
+            .map(|height| env.rpc_client().get_block_hash(height))
+            .collect::<Result<Vec<_>, _>>()?;
+        hashes.extend(env.mine_blocks(101 - network_tip as usize, None)?);
         hashes
     };
 
-    // see if the emitter outputs the right blocks
+    // See if the emitter outputs the right blocks.
     println!("first sync:");
-    while let Some((height, block)) = emitter.next_block()? {
+    while let Some(emission) = emitter.next_block()? {
+        let height = emission.block_height();
+        let hash = emission.block_hash();
         assert_eq!(
-            block.block_hash(),
+            emission.block_hash(),
             exp_hashes[height as usize],
             "emitted block hash is unexpected"
         );
 
-        let chain_update = block_to_chain_update(&block, height);
         assert_eq!(
-            local_chain.apply_update(chain_update)?,
-            BTreeMap::from([(height, Some(block.block_hash()))]),
+            local_chain.apply_update(emission.checkpoint,)?,
+            BTreeMap::from([(height, Some(hash))]),
             "chain update changeset is unexpected",
         );
     }
 
     assert_eq!(
-        local_chain.blocks(),
-        &exp_hashes
+        local_chain
+            .iter_checkpoints()
+            .map(|cp| (cp.height(), cp.hash()))
+            .collect::<BTreeSet<_>>(),
+        exp_hashes
             .iter()
             .enumerate()
             .map(|(i, hash)| (i as u32, *hash))
-            .collect(),
+            .collect::<BTreeSet<_>>(),
         "final local_chain state is unexpected",
     );
 
-    // perform reorg
+    // Perform reorg.
     let reorged_blocks = env.reorg(6)?;
     let exp_hashes = exp_hashes
         .iter()
@@ -234,30 +75,30 @@ pub fn test_sync_local_chain() -> anyhow::Result<()> {
         .cloned()
         .collect::<Vec<_>>();
 
-    // see if the emitter outputs the right blocks
+    // See if the emitter outputs the right blocks.
     println!("after reorg:");
     let mut exp_height = exp_hashes.len() - reorged_blocks.len();
-    while let Some((height, block)) = emitter.next_block()? {
+    while let Some(emission) = emitter.next_block()? {
+        let height = emission.block_height();
+        let hash = emission.block_hash();
         assert_eq!(
             height, exp_height as u32,
             "emitted block has unexpected height"
         );
 
         assert_eq!(
-            block.block_hash(),
-            exp_hashes[height as usize],
+            hash, exp_hashes[height as usize],
             "emitted block is unexpected"
         );
 
-        let chain_update = block_to_chain_update(&block, height);
         assert_eq!(
-            local_chain.apply_update(chain_update)?,
+            local_chain.apply_update(emission.checkpoint,)?,
             if exp_height == exp_hashes.len() - reorged_blocks.len() {
-                core::iter::once((height, Some(block.block_hash())))
+                core::iter::once((height, Some(hash)))
                     .chain((height + 1..exp_hashes.len() as u32).map(|h| (h, None)))
                     .collect::<bdk_chain::local_chain::ChangeSet>()
             } else {
-                BTreeMap::from([(height, Some(block.block_hash()))])
+                BTreeMap::from([(height, Some(hash))])
             },
             "chain update changeset is unexpected",
         );
@@ -266,12 +107,15 @@ pub fn test_sync_local_chain() -> anyhow::Result<()> {
     }
 
     assert_eq!(
-        local_chain.blocks(),
-        &exp_hashes
+        local_chain
+            .iter_checkpoints()
+            .map(|cp| (cp.height(), cp.hash()))
+            .collect::<BTreeSet<_>>(),
+        exp_hashes
             .iter()
             .enumerate()
             .map(|(i, hash)| (i as u32, *hash))
-            .collect(),
+            .collect::<BTreeSet<_>>(),
         "final local_chain state is unexpected after reorg",
     );
 
@@ -287,16 +131,25 @@ fn test_into_tx_graph() -> anyhow::Result<()> {
     let env = TestEnv::new()?;
 
     println!("getting new addresses!");
-    let addr_0 = env.client.get_new_address(None, None)?.assume_checked();
-    let addr_1 = env.client.get_new_address(None, None)?.assume_checked();
-    let addr_2 = env.client.get_new_address(None, None)?.assume_checked();
+    let addr_0 = env
+        .rpc_client()
+        .get_new_address(None, None)?
+        .assume_checked();
+    let addr_1 = env
+        .rpc_client()
+        .get_new_address(None, None)?
+        .assume_checked();
+    let addr_2 = env
+        .rpc_client()
+        .get_new_address(None, None)?
+        .assume_checked();
     println!("got new addresses!");
 
     println!("mining block!");
     env.mine_blocks(101, None)?;
     println!("mined blocks!");
 
-    let (mut chain, _) = LocalChain::from_genesis_hash(env.client.get_block_hash(0)?);
+    let (mut chain, _) = LocalChain::from_genesis_hash(env.rpc_client().get_block_hash(0)?);
     let mut indexed_tx_graph = IndexedTxGraph::<BlockId, _>::new({
         let mut index = SpkTxOutIndex::<usize>::default();
         index.insert_spk(0, addr_0.script_pubkey());
@@ -305,11 +158,12 @@ fn test_into_tx_graph() -> anyhow::Result<()> {
         index
     });
 
-    let emitter = &mut Emitter::new(&env.client, chain.tip(), 0);
+    let emitter = &mut Emitter::new(env.rpc_client(), chain.tip(), 0);
 
-    while let Some((height, block)) = emitter.next_block()? {
-        let _ = chain.apply_update(block_to_chain_update(&block, height))?;
-        let indexed_additions = indexed_tx_graph.apply_block_relevant(block, height);
+    while let Some(emission) = emitter.next_block()? {
+        let height = emission.block_height();
+        let _ = chain.apply_update(emission.checkpoint)?;
+        let indexed_additions = indexed_tx_graph.apply_block_relevant(&emission.block, height);
         assert!(indexed_additions.is_empty());
     }
 
@@ -317,7 +171,7 @@ fn test_into_tx_graph() -> anyhow::Result<()> {
     let exp_txids = {
         let mut txids = BTreeSet::new();
         for _ in 0..3 {
-            txids.insert(env.client.send_to_address(
+            txids.insert(env.rpc_client().send_to_address(
                 &addr_0,
                 Amount::from_sat(10_000),
                 None,
@@ -353,7 +207,7 @@ fn test_into_tx_graph() -> anyhow::Result<()> {
 
     // mine a block that confirms the 3 txs
     let exp_block_hash = env.mine_blocks(1, None)?[0];
-    let exp_block_height = env.client.get_block_info(&exp_block_hash)?.height as u32;
+    let exp_block_height = env.rpc_client().get_block_info(&exp_block_hash)?.height as u32;
     let exp_anchors = exp_txids
         .iter()
         .map({
@@ -367,10 +221,10 @@ fn test_into_tx_graph() -> anyhow::Result<()> {
 
     // must receive mined block which will confirm the transactions.
     {
-        let (height, block) = emitter.next_block()?.expect("must get mined block");
-        let _ = chain
-            .apply_update(CheckPoint::from_header(&block.header, height).into_update(false))?;
-        let indexed_additions = indexed_tx_graph.apply_block_relevant(block, height);
+        let emission = emitter.next_block()?.expect("must get mined block");
+        let height = emission.block_height();
+        let _ = chain.apply_update(emission.checkpoint)?;
+        let indexed_additions = indexed_tx_graph.apply_block_relevant(&emission.block, height);
         assert!(indexed_additions.graph.txs.is_empty());
         assert!(indexed_additions.graph.txouts.is_empty());
         assert_eq!(indexed_additions.graph.anchors, exp_anchors);
@@ -394,10 +248,10 @@ fn ensure_block_emitted_after_reorg_is_at_reorg_height() -> anyhow::Result<()> {
 
     let env = TestEnv::new()?;
     let mut emitter = Emitter::new(
-        &env.client,
+        env.rpc_client(),
         CheckPoint::new(BlockId {
             height: 0,
-            hash: env.client.get_block_hash(0)?,
+            hash: env.rpc_client().get_block_hash(0)?,
         }),
         EMITTER_START_HEIGHT as _,
     );
@@ -407,9 +261,12 @@ fn ensure_block_emitted_after_reorg_is_at_reorg_height() -> anyhow::Result<()> {
 
     for reorg_count in 1..=10 {
         let replaced_blocks = env.reorg_empty_blocks(reorg_count)?;
-        let (height, next_header) = emitter.next_header()?.expect("must emit block after reorg");
+        let next_emission = emitter.next_header()?.expect("must emit block after reorg");
         assert_eq!(
-            (height as usize, next_header.block_hash()),
+            (
+                next_emission.block_height() as usize,
+                next_emission.block_hash()
+            ),
             replaced_blocks[0],
             "block emitted after reorg should be at the reorg height"
         );
@@ -425,8 +282,7 @@ fn process_block(
     block: Block,
     block_height: u32,
 ) -> anyhow::Result<()> {
-    recv_chain
-        .apply_update(CheckPoint::from_header(&block.header, block_height).into_update(false))?;
+    recv_chain.apply_update(CheckPoint::from_header(&block.header, block_height))?;
     let _ = recv_graph.apply_block(block, block_height);
     Ok(())
 }
@@ -439,8 +295,9 @@ fn sync_from_emitter<C>(
 where
     C: bitcoincore_rpc::RpcApi,
 {
-    while let Some((height, block)) = emitter.next_block()? {
-        process_block(recv_chain, recv_graph, block, height)?;
+    while let Some(emission) = emitter.next_block()? {
+        let height = emission.block_height();
+        process_block(recv_chain, recv_graph, emission.block, height)?;
     }
     Ok(())
 }
@@ -467,21 +324,24 @@ fn tx_can_become_unconfirmed_after_reorg() -> anyhow::Result<()> {
 
     let env = TestEnv::new()?;
     let mut emitter = Emitter::new(
-        &env.client,
+        env.rpc_client(),
         CheckPoint::new(BlockId {
             height: 0,
-            hash: env.client.get_block_hash(0)?,
+            hash: env.rpc_client().get_block_hash(0)?,
         }),
         0,
     );
 
     // setup addresses
-    let addr_to_mine = env.client.get_new_address(None, None)?.assume_checked();
-    let spk_to_track = ScriptBuf::new_v0_p2wsh(&WScriptHash::all_zeros());
+    let addr_to_mine = env
+        .rpc_client()
+        .get_new_address(None, None)?
+        .assume_checked();
+    let spk_to_track = ScriptBuf::new_p2wsh(&WScriptHash::all_zeros());
     let addr_to_track = Address::from_script(&spk_to_track, bitcoin::Network::Regtest)?;
 
     // setup receiver
-    let (mut recv_chain, _) = LocalChain::from_genesis_hash(env.client.get_block_hash(0)?);
+    let (mut recv_chain, _) = LocalChain::from_genesis_hash(env.rpc_client().get_block_hash(0)?);
     let mut recv_graph = IndexedTxGraph::<BlockId, _>::new({
         let mut recv_index = SpkTxOutIndex::default();
         recv_index.insert_spk((), spk_to_track.clone());
@@ -497,7 +357,7 @@ fn tx_can_become_unconfirmed_after_reorg() -> anyhow::Result<()> {
 
         // lock outputs that send to `addr_to_track`
         let outpoints_to_lock = env
-            .client
+            .rpc_client()
             .get_transaction(&txid, None)?
             .transaction()?
             .output
@@ -506,7 +366,7 @@ fn tx_can_become_unconfirmed_after_reorg() -> anyhow::Result<()> {
             .filter(|(_, txo)| txo.script_pubkey == spk_to_track)
             .map(|(vout, _)| OutPoint::new(txid, vout as _))
             .collect::<Vec<_>>();
-        env.client.lock_unspent(&outpoints_to_lock)?;
+        env.rpc_client().lock_unspent(&outpoints_to_lock)?;
 
         let _ = env.mine_blocks(1, None)?;
     }
@@ -517,7 +377,7 @@ fn tx_can_become_unconfirmed_after_reorg() -> anyhow::Result<()> {
     assert_eq!(
         get_balance(&recv_chain, &recv_graph)?,
         Balance {
-            confirmed: SEND_AMOUNT.to_sat() * ADDITIONAL_COUNT as u64,
+            confirmed: SEND_AMOUNT * ADDITIONAL_COUNT as u64,
             ..Balance::default()
         },
         "initial balance must be correct",
@@ -531,8 +391,8 @@ fn tx_can_become_unconfirmed_after_reorg() -> anyhow::Result<()> {
         assert_eq!(
             get_balance(&recv_chain, &recv_graph)?,
             Balance {
-                confirmed: SEND_AMOUNT.to_sat() * (ADDITIONAL_COUNT - reorg_count) as u64,
-                trusted_pending: SEND_AMOUNT.to_sat() * reorg_count as u64,
+                confirmed: SEND_AMOUNT * (ADDITIONAL_COUNT - reorg_count) as u64,
+                trusted_pending: SEND_AMOUNT * reorg_count as u64,
                 ..Balance::default()
             },
             "reorg_count: {}",
@@ -555,16 +415,19 @@ fn mempool_avoids_re_emission() -> anyhow::Result<()> {
 
     let env = TestEnv::new()?;
     let mut emitter = Emitter::new(
-        &env.client,
+        env.rpc_client(),
         CheckPoint::new(BlockId {
             height: 0,
-            hash: env.client.get_block_hash(0)?,
+            hash: env.rpc_client().get_block_hash(0)?,
         }),
         0,
     );
 
     // mine blocks and sync up emitter
-    let addr = env.client.get_new_address(None, None)?.assume_checked();
+    let addr = env
+        .rpc_client()
+        .get_new_address(None, None)?
+        .assume_checked();
     env.mine_blocks(BLOCKS_TO_MINE, Some(addr.clone()))?;
     while emitter.next_header()?.is_some() {}
 
@@ -617,16 +480,19 @@ fn mempool_re_emits_if_tx_introduction_height_not_reached() -> anyhow::Result<()
 
     let env = TestEnv::new()?;
     let mut emitter = Emitter::new(
-        &env.client,
+        env.rpc_client(),
         CheckPoint::new(BlockId {
             height: 0,
-            hash: env.client.get_block_hash(0)?,
+            hash: env.rpc_client().get_block_hash(0)?,
         }),
         0,
     );
 
     // mine blocks to get initial balance, sync emitter up to tip
-    let addr = env.client.get_new_address(None, None)?.assume_checked();
+    let addr = env
+        .rpc_client()
+        .get_new_address(None, None)?
+        .assume_checked();
     env.mine_blocks(PREMINE_COUNT, Some(addr.clone()))?;
     while emitter.next_header()?.is_some() {}
 
@@ -660,7 +526,8 @@ fn mempool_re_emits_if_tx_introduction_height_not_reached() -> anyhow::Result<()
 
     // At this point, the emitter has seen all mempool transactions. It should only re-emit those
     // that have introduction heights less than the emitter's last-emitted block tip.
-    while let Some((height, _)) = emitter.next_header()? {
+    while let Some(emission) = emitter.next_header()? {
+        let height = emission.block_height();
         // We call `mempool()` twice.
         // The second call (at height `h`) should skip the tx introduced at height `h`.
         for try_index in 0..2 {
@@ -701,16 +568,19 @@ fn mempool_during_reorg() -> anyhow::Result<()> {
 
     let env = TestEnv::new()?;
     let mut emitter = Emitter::new(
-        &env.client,
+        env.rpc_client(),
         CheckPoint::new(BlockId {
             height: 0,
-            hash: env.client.get_block_hash(0)?,
+            hash: env.rpc_client().get_block_hash(0)?,
         }),
         0,
     );
 
     // mine blocks to get initial balance
-    let addr = env.client.get_new_address(None, None)?.assume_checked();
+    let addr = env
+        .rpc_client()
+        .get_new_address(None, None)?
+        .assume_checked();
     env.mine_blocks(PREMINE_COUNT, Some(addr.clone()))?;
 
     // introduce mempool tx at each block extension
@@ -728,7 +598,7 @@ fn mempool_during_reorg() -> anyhow::Result<()> {
             .into_iter()
             .map(|(tx, _)| tx.txid())
             .collect::<BTreeSet<_>>(),
-        env.client
+        env.rpc_client()
             .get_raw_mempool()?
             .into_iter()
             .collect::<BTreeSet<_>>(),
@@ -747,14 +617,15 @@ fn mempool_during_reorg() -> anyhow::Result<()> {
         // emission.
         // TODO: How can have have reorg logic in `TestEnv` NOT blacklast old blocks first?
         let tx_introductions = dbg!(env
-            .client
+            .rpc_client()
             .get_raw_mempool_verbose()?
             .into_iter()
             .map(|(txid, entry)| (txid, entry.height as usize))
             .collect::<BTreeMap<_, _>>());
 
         // `next_header` emits the replacement block of the reorg
-        if let Some((height, _)) = emitter.next_header()? {
+        if let Some(emission) = emitter.next_header()? {
+            let height = emission.block_height();
             println!("\t- replacement height: {}", height);
 
             // the mempool emission (that follows the first block emission after reorg) should only
@@ -823,10 +694,10 @@ fn no_agreement_point() -> anyhow::Result<()> {
 
     // start height is 99
     let mut emitter = Emitter::new(
-        &env.client,
+        env.rpc_client(),
         CheckPoint::new(BlockId {
             height: 0,
-            hash: env.client.get_block_hash(0)?,
+            hash: env.rpc_client().get_block_hash(0)?,
         }),
         (PREMINE_COUNT - 2) as u32,
     );
@@ -835,27 +706,27 @@ fn no_agreement_point() -> anyhow::Result<()> {
     env.mine_blocks(PREMINE_COUNT, None)?;
 
     // emit block 99a
-    let (_, block_header_99a) = emitter.next_header()?.expect("block 99a header");
+    let block_header_99a = emitter.next_header()?.expect("block 99a header").block;
     let block_hash_99a = block_header_99a.block_hash();
     let block_hash_98a = block_header_99a.prev_blockhash;
 
     // emit block 100a
-    let (_, block_header_100a) = emitter.next_header()?.expect("block 100a header");
+    let block_header_100a = emitter.next_header()?.expect("block 100a header").block;
     let block_hash_100a = block_header_100a.block_hash();
 
     // get hash for block 101a
-    let block_hash_101a = env.client.get_block_hash(101)?;
+    let block_hash_101a = env.rpc_client().get_block_hash(101)?;
 
     // invalidate blocks 99a, 100a, 101a
-    env.client.invalidate_block(&block_hash_99a)?;
-    env.client.invalidate_block(&block_hash_100a)?;
-    env.client.invalidate_block(&block_hash_101a)?;
+    env.rpc_client().invalidate_block(&block_hash_99a)?;
+    env.rpc_client().invalidate_block(&block_hash_100a)?;
+    env.rpc_client().invalidate_block(&block_hash_101a)?;
 
     // mine new blocks 99b, 100b, 101b
     env.mine_blocks(3, None)?;
 
     // emit block header 99b
-    let (_, block_header_99b) = emitter.next_header()?.expect("block 99b header");
+    let block_header_99b = emitter.next_header()?.expect("block 99b header").block;
     let block_hash_99b = block_header_99b.block_hash();
     let block_hash_98b = block_header_99b.prev_blockhash;
 

crates/chain/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "bdk_chain"
-version = "0.6.0"
+version = "0.14.0"
 edition = "2021"
-rust-version = "1.57"
+rust-version = "1.63"
 homepage = "https://bitcoindevkit.org"
 repository = "https://github.com/bitcoindevkit/bdk"
 documentation = "https://docs.rs/bdk_chain"
@@ -14,18 +14,18 @@ readme = "README.md"
 
 [dependencies]
 # For no-std, remember to enable the bitcoin/no-std feature
-bitcoin = { version = "0.30.0", default-features = false }
-serde_crate = { package = "serde", version = "1", optional = true, features = ["derive"] }
+bitcoin = { version = "0.31.0", default-features = false }
+serde_crate = { package = "serde", version = "1", optional = true, features = ["derive", "rc"] }
 
 # Use hashbrown as a feature flag to have HashSet and HashMap from it.
-# note versions > 0.9.1 breaks ours 1.57.0 MSRV.
 hashbrown = { version = "0.9.1", optional = true, features = ["serde"] }
-miniscript = { version = "10.0.0", optional = true, default-features = false }
+miniscript = { version = "11.0.0", optional = true, default-features = false }
 
 [dev-dependencies]
 rand = "0.8"
+proptest = "1.2.0"
 
 [features]
-default = ["std"]
-std = ["bitcoin/std", "miniscript/std"]
-serde = ["serde_crate", "bitcoin/serde"]
+default = ["std", "miniscript"]
+std = ["bitcoin/std", "miniscript?/std"]
+serde = ["serde_crate", "bitcoin/serde", "miniscript?/serde"]

crates/chain/src/chain_data.rs

@@ -9,7 +9,7 @@ use crate::{Anchor, AnchorFromBlockPosition, COINBASE_MATURITY};
 pub enum ChainPosition<A> {
     /// The chain data is seen as confirmed, and in anchored by `A`.
     Confirmed(A),
-    /// The chain data is seen in mempool at this given timestamp.
+    /// The chain data is not confirmed and last seen in the mempool at this timestamp.
     Unconfirmed(u64),
 }
 
@@ -48,14 +48,14 @@ impl<A: Anchor> ChainPosition<A> {
     serde(crate = "serde_crate")
 )]
 pub enum ConfirmationTime {
-    /// The confirmed variant.
+    /// The transaction is confirmed
     Confirmed {
         /// Confirmation height.
         height: u32,
         /// Confirmation time in unix seconds.
         time: u64,
     },
-    /// The unconfirmed variant.
+    /// The transaction is unconfirmed
     Unconfirmed {
         /// The last-seen timestamp in unix seconds.
         last_seen: u64,
@@ -81,7 +81,7 @@ impl From<ChainPosition<ConfirmationTimeHeightAnchor>> for ConfirmationTime {
                 height: a.confirmation_height,
                 time: a.confirmation_time,
             },
-            ChainPosition::Unconfirmed(_) => Self::Unconfirmed { last_seen: 0 },
+            ChainPosition::Unconfirmed(last_seen) => Self::Unconfirmed { last_seen },
         }
     }
 }
@@ -147,6 +147,8 @@ impl From<(&u32, &BlockHash)> for BlockId {
 
 /// An [`Anchor`] implementation that also records the exact confirmation height of the transaction.
 ///
+/// Note that the confirmation block and the anchor block can be different here.
+///
 /// Refer to [`Anchor`] for more details.
 #[derive(Debug, Default, Clone, PartialEq, Eq, Copy, PartialOrd, Ord, core::hash::Hash)]
 #[cfg_attr(
@@ -155,13 +157,12 @@ impl From<(&u32, &BlockHash)> for BlockId {
     serde(crate = "serde_crate")
 )]
 pub struct ConfirmationHeightAnchor {
-    /// The anchor block.
-    pub anchor_block: BlockId,
-
     /// The exact confirmation height of the transaction.
     ///
     /// It is assumed that this value is never larger than the height of the anchor block.
     pub confirmation_height: u32,
+    /// The anchor block.
+    pub anchor_block: BlockId,
 }
 
 impl Anchor for ConfirmationHeightAnchor {
@@ -186,6 +187,8 @@ impl AnchorFromBlockPosition for ConfirmationHeightAnchor {
 /// An [`Anchor`] implementation that also records the exact confirmation time and height of the
 /// transaction.
 ///
+/// Note that the confirmation block and the anchor block can be different here.
+///
 /// Refer to [`Anchor`] for more details.
 #[derive(Debug, Default, Clone, PartialEq, Eq, Copy, PartialOrd, Ord, core::hash::Hash)]
 #[cfg_attr(
@@ -194,12 +197,12 @@ impl AnchorFromBlockPosition for ConfirmationHeightAnchor {
     serde(crate = "serde_crate")
 )]
 pub struct ConfirmationTimeHeightAnchor {
+    /// The confirmation height of the transaction being anchored.
+    pub confirmation_height: u32,
+    /// The confirmation time of the transaction being anchored.
+    pub confirmation_time: u64,
     /// The anchor block.
     pub anchor_block: BlockId,
-    /// The confirmation height of the chain data being anchored.
-    pub confirmation_height: u32,
-    /// The confirmation time of the chain data being anchored.
-    pub confirmation_time: u64,
 }
 
 impl Anchor for ConfirmationTimeHeightAnchor {
@@ -225,12 +228,12 @@ impl AnchorFromBlockPosition for ConfirmationTimeHeightAnchor {
 /// A `TxOut` with as much data as we can retrieve about it
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct FullTxOut<A> {
+    /// The position of the transaction in `outpoint` in the overall chain.
+    pub chain_position: ChainPosition<A>,
     /// The location of the `TxOut`.
     pub outpoint: OutPoint,
     /// The `TxOut`.
     pub txout: TxOut,
-    /// The position of the transaction in `outpoint` in the overall chain.
-    pub chain_position: ChainPosition<A>,
     /// The txid and chain position of the transaction (if any) that has spent this output.
     pub spent_by: Option<(ChainPosition<A>, Txid)>,
     /// Whether this output is on a coinbase transaction.
@@ -295,3 +298,35 @@ impl<A: Anchor> FullTxOut<A> {
         true
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn chain_position_ord() {
+        let unconf1 = ChainPosition::<ConfirmationHeightAnchor>::Unconfirmed(10);
+        let unconf2 = ChainPosition::<ConfirmationHeightAnchor>::Unconfirmed(20);
+        let conf1 = ChainPosition::Confirmed(ConfirmationHeightAnchor {
+            confirmation_height: 9,
+            anchor_block: BlockId {
+                height: 20,
+                ..Default::default()
+            },
+        });
+        let conf2 = ChainPosition::Confirmed(ConfirmationHeightAnchor {
+            confirmation_height: 12,
+            anchor_block: BlockId {
+                height: 15,
+                ..Default::default()
+            },
+        });
+
+        assert!(unconf2 > unconf1, "higher last_seen means higher ord");
+        assert!(unconf1 > conf1, "unconfirmed is higher ord than confirmed");
+        assert!(
+            conf2 > conf1,
+            "confirmation_height is higher then it should be higher ord"
+        );
+    }
+}

crates/chain/src/chain_oracle.rs

@@ -3,7 +3,7 @@ use crate::BlockId;
 /// Represents a service that tracks the blockchain.
 ///
 /// The main method is [`is_block_in_chain`] which determines whether a given block of [`BlockId`]
-/// is an ancestor of another "static block".
+/// is an ancestor of the `chain_tip`.
 ///
 /// [`is_block_in_chain`]: Self::is_block_in_chain
 pub trait ChainOracle {

crates/chain/src/descriptor_ext.rs

@@ -1,10 +1,29 @@
-use crate::miniscript::{Descriptor, DescriptorPublicKey};
+use crate::{
+    alloc::{string::ToString, vec::Vec},
+    miniscript::{Descriptor, DescriptorPublicKey},
+};
+use bitcoin::hashes::{hash_newtype, sha256, Hash};
+
+hash_newtype! {
+    /// Represents the ID of a descriptor, defined as the sha256 hash of
+    /// the descriptor string, checksum excluded.
+    ///
+    /// This is useful for having a fixed-length unique representation of a descriptor,
+    /// in particular, we use it to persist application state changes related to the
+    /// descriptor without having to re-write the whole descriptor each time.
+    ///
+    pub struct DescriptorId(pub sha256::Hash);
+}
 
 /// A trait to extend the functionality of a miniscript descriptor.
 pub trait DescriptorExt {
     /// Returns the minimum value (in satoshis) at which an output is broadcastable.
     /// Panics if the descriptor wildcard is hardened.
     fn dust_value(&self) -> u64;
+
+    /// Returns the descriptor id, calculated as the sha256 of the descriptor, checksum not
+    /// included.
+    fn descriptor_id(&self) -> DescriptorId;
 }
 
 impl DescriptorExt for Descriptor<DescriptorPublicKey> {
@@ -15,4 +34,11 @@ impl DescriptorExt for Descriptor<DescriptorPublicKey> {
             .dust_value()
             .to_sat()
     }
+
+    fn descriptor_id(&self) -> DescriptorId {
+        let desc = self.to_string();
+        let desc_without_checksum = desc.split('#').next().expect("Must be here");
+        let descriptor_bytes = <Vec<u8>>::from(desc_without_checksum.as_bytes());
+        DescriptorId(sha256::Hash::hash(&descriptor_bytes))
+    }
 }

crates/chain/src/indexed_tx_graph.rs

@@ -1,19 +1,16 @@
-//! Contains the [`IndexedTxGraph`] structure and associated types.
-//!
-//! This is essentially a [`TxGraph`] combined with an indexer.
-
+//! Contains the [`IndexedTxGraph`] and associated types. Refer to the
+//! [`IndexedTxGraph`] documentation for more.
 use alloc::vec::Vec;
 use bitcoin::{Block, OutPoint, Transaction, TxOut, Txid};
 
 use crate::{
-    keychain,
     tx_graph::{self, TxGraph},
     Anchor, AnchorFromBlockPosition, Append, BlockId,
 };
 
-/// A struct that combines [`TxGraph`] and an [`Indexer`] implementation.
+/// The [`IndexedTxGraph`] combines a [`TxGraph`] and an [`Indexer`] implementation.
 ///
-/// This structure ensures that [`TxGraph`] and [`Indexer`] are updated atomically.
+/// It ensures that [`TxGraph`] and [`Indexer`] are updated atomically.
 #[derive(Debug)]
 pub struct IndexedTxGraph<A, I> {
     /// Transaction index.
@@ -226,20 +223,26 @@ where
     /// Irrelevant transactions in `txs` will be ignored.
     pub fn apply_block_relevant(
         &mut self,
-        block: Block,
+        block: &Block,
         height: u32,
     ) -> ChangeSet<A, I::ChangeSet> {
         let block_id = BlockId {
             hash: block.block_hash(),
             height,
         };
-        let txs = block.txdata.iter().enumerate().map(|(tx_pos, tx)| {
-            (
-                tx,
-                core::iter::once(A::from_block_position(&block, block_id, tx_pos)),
-            )
-        });
-        self.batch_insert_relevant(txs)
+        let mut changeset = ChangeSet::<A, I::ChangeSet>::default();
+        for (tx_pos, tx) in block.txdata.iter().enumerate() {
+            changeset.indexer.append(self.index.index_tx(tx));
+            if self.index.is_tx_relevant(tx) {
+                let txid = tx.txid();
+                let anchor = A::from_block_position(block, block_id, tx_pos);
+                changeset.graph.append(self.graph.insert_tx(tx.clone()));
+                changeset
+                    .graph
+                    .append(self.graph.insert_anchor(txid, anchor));
+            }
+        }
+        changeset
     }
 
     /// Batch insert all transactions of the given `block` of `height`.
@@ -266,7 +269,7 @@ where
     }
 }
 
-/// A structure that represents changes to an [`IndexedTxGraph`].
+/// Represents changes to an [`IndexedTxGraph`].
 #[derive(Clone, Debug, PartialEq)]
 #[cfg_attr(
     feature = "serde",
@@ -316,8 +319,9 @@ impl<A, IA: Default> From<tx_graph::ChangeSet<A>> for ChangeSet<A, IA> {
     }
 }
 
-impl<A, K> From<keychain::ChangeSet<K>> for ChangeSet<A, keychain::ChangeSet<K>> {
-    fn from(indexer: keychain::ChangeSet<K>) -> Self {
+#[cfg(feature = "miniscript")]
+impl<A, K> From<crate::keychain::ChangeSet<K>> for ChangeSet<A, crate::keychain::ChangeSet<K>> {
+    fn from(indexer: crate::keychain::ChangeSet<K>) -> Self {
         Self {
             graph: Default::default(),
             indexer,

crates/chain/src/keychain.rs

@@ -10,76 +10,12 @@
 //!
 //! [`SpkTxOutIndex`]: crate::SpkTxOutIndex
 
-use crate::{collections::BTreeMap, Append};
-
 #[cfg(feature = "miniscript")]
 mod txout_index;
+use bitcoin::Amount;
 #[cfg(feature = "miniscript")]
 pub use txout_index::*;
 
-/// Represents updates to the derivation index of a [`KeychainTxOutIndex`].
-/// It maps each keychain `K` to its last revealed index.
-///
-/// It can be applied to [`KeychainTxOutIndex`] with [`apply_changeset`]. [`ChangeSet] are
-/// monotone in that they will never decrease the revealed derivation index.
-///
-/// [`KeychainTxOutIndex`]: crate::keychain::KeychainTxOutIndex
-/// [`apply_changeset`]: crate::keychain::KeychainTxOutIndex::apply_changeset
-#[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(
-    feature = "serde",
-    derive(serde::Deserialize, serde::Serialize),
-    serde(
-        crate = "serde_crate",
-        bound(
-            deserialize = "K: Ord + serde::Deserialize<'de>",
-            serialize = "K: Ord + serde::Serialize"
-        )
-    )
-)]
-#[must_use]
-pub struct ChangeSet<K>(pub BTreeMap<K, u32>);
-
-impl<K> ChangeSet<K> {
-    /// Get the inner map of the keychain to its new derivation index.
-    pub fn as_inner(&self) -> &BTreeMap<K, u32> {
-        &self.0
-    }
-}
-
-impl<K: Ord> Append for ChangeSet<K> {
-    /// Append another [`ChangeSet`] into self.
-    ///
-    /// If the keychain already exists, increase the index when the other's index > self's index.
-    /// If the keychain did not exist, append the new keychain.
-    fn append(&mut self, mut other: Self) {
-        self.0.iter_mut().for_each(|(key, index)| {
-            if let Some(other_index) = other.0.remove(key) {
-                *index = other_index.max(*index);
-            }
-        });
-
-        self.0.append(&mut other.0);
-    }
-
-    /// Returns whether the changeset are empty.
-    fn is_empty(&self) -> bool {
-        self.0.is_empty()
-    }
-}
-
-impl<K> Default for ChangeSet<K> {
-    fn default() -> Self {
-        Self(Default::default())
-    }
-}
-
-impl<K> AsRef<BTreeMap<K, u32>> for ChangeSet<K> {
-    fn as_ref(&self) -> &BTreeMap<K, u32> {
-        &self.0
-    }
-}
-
 /// Balance, differentiated into various categories.
 #[derive(Debug, PartialEq, Eq, Clone, Default)]
 #[cfg_attr(
@@ -89,13 +25,13 @@ impl<K> AsRef<BTreeMap<K, u32>> for ChangeSet<K> {
 )]
 pub struct Balance {
     /// All coinbase outputs not yet matured
-    pub immature: u64,
+    pub immature: Amount,
     /// Unconfirmed UTXOs generated by a wallet tx
-    pub trusted_pending: u64,
+    pub trusted_pending: Amount,
     /// Unconfirmed UTXOs received from an external wallet
-    pub untrusted_pending: u64,
+    pub untrusted_pending: Amount,
     /// Confirmed and immediately spendable balance
-    pub confirmed: u64,
+    pub confirmed: Amount,
 }
 
 impl Balance {
@@ -103,12 +39,12 @@ impl Balance {
     ///
     /// This is the balance you can spend right now that shouldn't get cancelled via another party
     /// double spending it.
-    pub fn trusted_spendable(&self) -> u64 {
+    pub fn trusted_spendable(&self) -> Amount {
         self.confirmed + self.trusted_pending
     }
 
     /// Get the whole balance visible to the wallet.
-    pub fn total(&self) -> u64 {
+    pub fn total(&self) -> Amount {
         self.confirmed + self.trusted_pending + self.untrusted_pending + self.immature
     }
 }
@@ -135,40 +71,3 @@ impl core::ops::Add for Balance {
         }
     }
 }
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    #[test]
-    fn append_keychain_derivation_indices() {
-        #[derive(Ord, PartialOrd, Eq, PartialEq, Clone, Debug)]
-        enum Keychain {
-            One,
-            Two,
-            Three,
-            Four,
-        }
-        let mut lhs_di = BTreeMap::<Keychain, u32>::default();
-        let mut rhs_di = BTreeMap::<Keychain, u32>::default();
-        lhs_di.insert(Keychain::One, 7);
-        lhs_di.insert(Keychain::Two, 0);
-        rhs_di.insert(Keychain::One, 3);
-        rhs_di.insert(Keychain::Two, 5);
-        lhs_di.insert(Keychain::Three, 3);
-        rhs_di.insert(Keychain::Four, 4);
-
-        let mut lhs = ChangeSet(lhs_di);
-        let rhs = ChangeSet(rhs_di);
-        lhs.append(rhs);
-
-        // Exiting index doesn't update if the new index in `other` is lower than `self`.
-        assert_eq!(lhs.0.get(&Keychain::One), Some(&7));
-        // Existing index updates if the new index in `other` is higher than `self`.
-        assert_eq!(lhs.0.get(&Keychain::Two), Some(&5));
-        // Existing index is unchanged if keychain doesn't exist in `other`.
-        assert_eq!(lhs.0.get(&Keychain::Three), Some(&3));
-        // New keychain gets added if the keychain is in `other` but not in `self`.
-        assert_eq!(lhs.0.get(&Keychain::Four), Some(&4));
-    }
-}

crates/chain/src/lib.rs

@@ -1,4 +1,4 @@
-//! This crate is a collection of core structures for [Bitcoin Dev Kit] (alpha release).
+//! This crate is a collection of core structures for [Bitcoin Dev Kit].
 //!
 //! The goal of this crate is to give wallets the mechanisms needed to:
 //!
@@ -12,9 +12,8 @@
 //!    you do it synchronously or asynchronously. If you know a fact about the blockchain, you can just
 //!    tell `bdk_chain`'s APIs about it, and that information will be integrated, if it can be done
 //!    consistently.
-//! 2. Error-free APIs.
-//! 3. Data persistence agnostic -- `bdk_chain` does not care where you cache on-chain data, what you
-//!    cache or how you fetch it.
+//! 2. Data persistence agnostic -- `bdk_chain` does not care where you cache on-chain data, what you
+//!    cache or how you retrieve it from persistent storage.
 //!
 //! [Bitcoin Dev Kit]: https://bitcoindevkit.org/
 
@@ -36,8 +35,6 @@ pub use tx_data_traits::*;
 pub use tx_graph::TxGraph;
 mod chain_oracle;
 pub use chain_oracle::*;
-mod persist;
-pub use persist::*;
 
 #[doc(hidden)]
 pub mod example_utils;
@@ -47,11 +44,12 @@ pub use miniscript;
 #[cfg(feature = "miniscript")]
 mod descriptor_ext;
 #[cfg(feature = "miniscript")]
-pub use descriptor_ext::DescriptorExt;
+pub use descriptor_ext::{DescriptorExt, DescriptorId};
 #[cfg(feature = "miniscript")]
 mod spk_iter;
 #[cfg(feature = "miniscript")]
 pub use spk_iter::*;
+pub mod spk_client;
 
 #[allow(unused_imports)]
 #[macro_use]

crates/chain/src/local_chain.rs

@@ -1,13 +1,15 @@
 //! The [`LocalChain`] is a local implementation of [`ChainOracle`].
 
 use core::convert::Infallible;
+use core::ops::RangeBounds;
 
 use crate::collections::BTreeMap;
 use crate::{BlockId, ChainOracle};
 use alloc::sync::Arc;
+use bitcoin::block::Header;
 use bitcoin::BlockHash;
 
-/// A structure that represents changes to [`LocalChain`].
+/// The [`ChangeSet`] represents changes to [`LocalChain`].
 ///
 /// The key represents the block height, and the value either represents added a new [`CheckPoint`]
 /// (if [`Some`]), or removing a [`CheckPoint`] (if [`None`]).
@@ -33,12 +35,42 @@ struct CPInner {
     prev: Option<Arc<CPInner>>,
 }
 
+impl PartialEq for CheckPoint {
+    fn eq(&self, other: &Self) -> bool {
+        let self_cps = self.iter().map(|cp| cp.block_id());
+        let other_cps = other.iter().map(|cp| cp.block_id());
+        self_cps.eq(other_cps)
+    }
+}
+
 impl CheckPoint {
     /// Construct a new base block at the front of a linked list.
     pub fn new(block: BlockId) -> Self {
         Self(Arc::new(CPInner { block, prev: None }))
     }
 
+    /// Construct a checkpoint from a list of [`BlockId`]s in ascending height order.
+    ///
+    /// # Errors
+    ///
+    /// This method will error if any of the follow occurs:
+    ///
+    /// - The `blocks` iterator is empty, in which case, the error will be `None`.
+    /// - The `blocks` iterator is not in ascending height order.
+    /// - The `blocks` iterator contains multiple [`BlockId`]s of the same height.
+    ///
+    /// The error type is the last successful checkpoint constructed (if any).
+    pub fn from_block_ids(
+        block_ids: impl IntoIterator<Item = BlockId>,
+    ) -> Result<Self, Option<Self>> {
+        let mut blocks = block_ids.into_iter();
+        let mut acc = CheckPoint::new(blocks.next().ok_or(None)?);
+        for id in blocks {
+            acc = acc.push(id).map_err(Some)?;
+        }
+        Ok(acc)
+    }
+
     /// Construct a checkpoint from the given `header` and block `height`.
     ///
     /// If `header` is of the genesis block, the checkpoint won't have a [`prev`] node. Otherwise,
@@ -64,16 +96,6 @@ impl CheckPoint {
             .expect("must construct checkpoint")
     }
 
-    /// Convenience method to convert the [`CheckPoint`] into an [`Update`].
-    ///
-    /// For more information, refer to [`Update`].
-    pub fn into_update(self, introduce_older_blocks: bool) -> Update {
-        Update {
-            tip: self,
-            introduce_older_blocks,
-        }
-    }
-
     /// Puts another checkpoint onto the linked list representing the blockchain.
     ///
     /// Returns an `Err(self)` if the block you are pushing on is not at a greater height that the one you
@@ -125,237 +147,82 @@ impl CheckPoint {
     pub fn iter(&self) -> CheckPointIter {
         self.clone().into_iter()
     }
-}
 
-/// A structure that iterates over checkpoints backwards.
-pub struct CheckPointIter {
-    current: Option<Arc<CPInner>>,
-}
-
-impl Iterator for CheckPointIter {
-    type Item = CheckPoint;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        let current = self.current.clone()?;
-        self.current = current.prev.clone();
-        Some(CheckPoint(current))
-    }
-}
-
-impl IntoIterator for CheckPoint {
-    type Item = CheckPoint;
-    type IntoIter = CheckPointIter;
-
-    fn into_iter(self) -> Self::IntoIter {
-        CheckPointIter {
-            current: Some(self.0),
-        }
-    }
-}
-
-/// A struct to update [`LocalChain`].
-///
-/// This is used as input for [`LocalChain::apply_update`]. It contains the update's chain `tip` and
-/// a flag `introduce_older_blocks` which signals whether this update intends to introduce missing
-/// blocks to the original chain.
-///
-/// Block-by-block syncing mechanisms would typically create updates that builds upon the previous
-/// tip. In this case, `introduce_older_blocks` would be `false`.
-///
-/// Script-pubkey based syncing mechanisms may not introduce transactions in a chronological order
-/// so some updates require introducing older blocks (to anchor older transactions). For
-/// script-pubkey based syncing, `introduce_older_blocks` would typically be `true`.
-#[derive(Debug, Clone)]
-pub struct Update {
-    /// The update chain's new tip.
-    pub tip: CheckPoint,
-
-    /// Whether the update allows for introducing older blocks.
+    /// Get checkpoint at `height`.
     ///
-    /// Refer to [struct-level documentation] for more.
+    /// Returns `None` if checkpoint at `height` does not exist`.
+    pub fn get(&self, height: u32) -> Option<Self> {
+        self.range(height..=height).next()
+    }
+
+    /// Iterate checkpoints over a height range.
     ///
-    /// [struct-level documentation]: Update
-    pub introduce_older_blocks: bool,
-}
-
-/// This is a local implementation of [`ChainOracle`].
-#[derive(Debug, Clone)]
-pub struct LocalChain {
-    tip: CheckPoint,
-    index: BTreeMap<u32, BlockHash>,
-}
-
-impl PartialEq for LocalChain {
-    fn eq(&self, other: &Self) -> bool {
-        self.index == other.index
-    }
-}
-
-impl From<LocalChain> for BTreeMap<u32, BlockHash> {
-    fn from(value: LocalChain) -> Self {
-        value.index
-    }
-}
-
-impl ChainOracle for LocalChain {
-    type Error = Infallible;
-
-    fn is_block_in_chain(
-        &self,
-        block: BlockId,
-        chain_tip: BlockId,
-    ) -> Result<Option<bool>, Self::Error> {
-        if block.height > chain_tip.height {
-            return Ok(None);
-        }
-        Ok(
-            match (
-                self.index.get(&block.height),
-                self.index.get(&chain_tip.height),
-            ) {
-                (Some(cp), Some(tip_cp)) => Some(*cp == block.hash && *tip_cp == chain_tip.hash),
-                _ => None,
-            },
-        )
+    /// Note that we always iterate checkpoints in reverse height order (iteration starts at tip
+    /// height).
+    pub fn range<R>(&self, range: R) -> impl Iterator<Item = CheckPoint>
+    where
+        R: RangeBounds<u32>,
+    {
+        let start_bound = range.start_bound().cloned();
+        let end_bound = range.end_bound().cloned();
+        self.iter()
+            .skip_while(move |cp| match end_bound {
+                core::ops::Bound::Included(inc_bound) => cp.height() > inc_bound,
+                core::ops::Bound::Excluded(exc_bound) => cp.height() >= exc_bound,
+                core::ops::Bound::Unbounded => false,
+            })
+            .take_while(move |cp| match start_bound {
+                core::ops::Bound::Included(inc_bound) => cp.height() >= inc_bound,
+                core::ops::Bound::Excluded(exc_bound) => cp.height() > exc_bound,
+                core::ops::Bound::Unbounded => true,
+            })
     }
 
-    fn get_chain_tip(&self) -> Result<BlockId, Self::Error> {
-        Ok(self.tip.block_id())
-    }
-}
-
-impl LocalChain {
-    /// Get the genesis hash.
-    pub fn genesis_hash(&self) -> BlockHash {
-        self.index.get(&0).copied().expect("must have genesis hash")
-    }
-
-    /// Construct [`LocalChain`] from genesis `hash`.
+    /// Inserts `block_id` at its height within the chain.
+    ///
+    /// The effect of `insert` depends on whether a height already exists. If it doesn't the
+    /// `block_id` we inserted and all pre-existing blocks higher than it will be re-inserted after
+    /// it. If the height already existed and has a conflicting block hash then it will be purged
+    /// along with all block followin it. The returned chain will have a tip of the `block_id`
+    /// passed in. Of course, if the `block_id` was already present then this just returns `self`.
     #[must_use]
-    pub fn from_genesis_hash(hash: BlockHash) -> (Self, ChangeSet) {
-        let height = 0;
-        let chain = Self {
-            tip: CheckPoint::new(BlockId { height, hash }),
-            index: core::iter::once((height, hash)).collect(),
-        };
-        let changeset = chain.initial_changeset();
-        (chain, changeset)
-    }
+    pub fn insert(self, block_id: BlockId) -> Self {
+        assert_ne!(block_id.height, 0, "cannot insert the genesis block");
 
-    /// Construct a [`LocalChain`] from an initial `changeset`.
-    pub fn from_changeset(changeset: ChangeSet) -> Result<Self, MissingGenesisError> {
-        let genesis_entry = changeset.get(&0).copied().flatten();
-        let genesis_hash = match genesis_entry {
-            Some(hash) => hash,
-            None => return Err(MissingGenesisError),
-        };
-
-        let (mut chain, _) = Self::from_genesis_hash(genesis_hash);
-        chain.apply_changeset(&changeset)?;
-
-        debug_assert!(chain._check_index_is_consistent_with_tip());
-        debug_assert!(chain._check_changeset_is_applied(&changeset));
-
-        Ok(chain)
-    }
-
-    /// Construct a [`LocalChain`] from a given `checkpoint` tip.
-    pub fn from_tip(tip: CheckPoint) -> Result<Self, MissingGenesisError> {
-        let mut chain = Self {
-            tip,
-            index: BTreeMap::new(),
-        };
-        chain.reindex(0);
-
-        if chain.index.get(&0).copied().is_none() {
-            return Err(MissingGenesisError);
-        }
-
-        debug_assert!(chain._check_index_is_consistent_with_tip());
-        Ok(chain)
-    }
-
-    /// Constructs a [`LocalChain`] from a [`BTreeMap`] of height to [`BlockHash`].
-    ///
-    /// The [`BTreeMap`] enforces the height order. However, the caller must ensure the blocks are
-    /// all of the same chain.
-    pub fn from_blocks(blocks: BTreeMap<u32, BlockHash>) -> Result<Self, MissingGenesisError> {
-        if !blocks.contains_key(&0) {
-            return Err(MissingGenesisError);
-        }
-
-        let mut tip: Option<CheckPoint> = None;
-
-        for block in &blocks {
-            match tip {
-                Some(curr) => {
-                    tip = Some(
-                        curr.push(BlockId::from(block))
-                            .expect("BTreeMap is ordered"),
-                    )
+        let mut cp = self.clone();
+        let mut tail = vec![];
+        let base = loop {
+            if cp.height() == block_id.height {
+                if cp.hash() == block_id.hash {
+                    return self;
                 }
-                None => tip = Some(CheckPoint::new(BlockId::from(block))),
+                // if we have a conflict we just return the inserted block because the tail is by
+                // implication invalid.
+                tail = vec![];
+                break cp.prev().expect("can't be called on genesis block");
             }
-        }
 
-        let chain = Self {
-            index: blocks,
-            tip: tip.expect("already checked to have genesis"),
+            if cp.height() < block_id.height {
+                break cp;
+            }
+
+            tail.push(cp.block_id());
+            cp = cp.prev().expect("will break before genesis block");
         };
 
-        debug_assert!(chain._check_index_is_consistent_with_tip());
-        Ok(chain)
+        base.extend(core::iter::once(block_id).chain(tail.into_iter().rev()))
+            .expect("tail is in order")
     }
 
-    /// Get the highest checkpoint.
-    pub fn tip(&self) -> CheckPoint {
-        self.tip.clone()
-    }
-
-    /// Applies the given `update` to the chain.
-    ///
-    /// The method returns [`ChangeSet`] on success. This represents the applied changes to `self`.
-    ///
-    /// There must be no ambiguity about which of the existing chain's blocks are still valid and
-    /// which are now invalid. That is, the new chain must implicitly connect to a definite block in
-    /// the existing chain and invalidate the block after it (if it exists) by including a block at
-    /// the same height but with a different hash to explicitly exclude it as a connection point.
-    ///
-    /// Additionally, an empty chain can be updated with any chain, and a chain with a single block
-    /// can have it's block invalidated by an update chain with a block at the same height but
-    /// different hash.
-    ///
-    /// # Errors
-    ///
-    /// An error will occur if the update does not correctly connect with `self`.
-    ///
-    /// Refer to [`Update`] for more about the update struct.
-    ///
-    /// [module-level documentation]: crate::local_chain
-    pub fn apply_update(&mut self, update: Update) -> Result<ChangeSet, CannotConnectError> {
-        let changeset = merge_chains(
-            self.tip.clone(),
-            update.tip.clone(),
-            update.introduce_older_blocks,
-        )?;
-        // `._check_index_is_consistent_with_tip` and `._check_changeset_is_applied` is called in
-        // `.apply_changeset`
-        self.apply_changeset(&changeset)
-            .map_err(|_| CannotConnectError {
-                try_include_height: 0,
-            })?;
-        Ok(changeset)
-    }
-
-    /// Apply the given `changeset`.
-    pub fn apply_changeset(&mut self, changeset: &ChangeSet) -> Result<(), MissingGenesisError> {
+    /// Apply `changeset` to the checkpoint.
+    fn apply_changeset(mut self, changeset: &ChangeSet) -> Result<CheckPoint, MissingGenesisError> {
         if let Some(start_height) = changeset.keys().next().cloned() {
             // changes after point of agreement
             let mut extension = BTreeMap::default();
             // point of agreement
             let mut base: Option<CheckPoint> = None;
 
-            for cp in self.iter_checkpoints() {
+            for cp in self.iter() {
                 if cp.height() >= start_height {
                     extension.insert(cp.height(), cp.hash());
                 } else {
@@ -381,13 +248,257 @@ impl LocalChain {
                     .expect("extension is strictly greater than base"),
                 None => LocalChain::from_blocks(extension)?.tip(),
             };
-            self.tip = new_tip;
-            self.reindex(start_height);
-
-            debug_assert!(self._check_index_is_consistent_with_tip());
-            debug_assert!(self._check_changeset_is_applied(changeset));
+            self = new_tip;
         }
 
+        Ok(self)
+    }
+}
+
+/// Iterates over checkpoints backwards.
+pub struct CheckPointIter {
+    current: Option<Arc<CPInner>>,
+}
+
+impl Iterator for CheckPointIter {
+    type Item = CheckPoint;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let current = self.current.clone()?;
+        self.current.clone_from(&current.prev);
+        Some(CheckPoint(current))
+    }
+}
+
+impl IntoIterator for CheckPoint {
+    type Item = CheckPoint;
+    type IntoIter = CheckPointIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        CheckPointIter {
+            current: Some(self.0),
+        }
+    }
+}
+
+/// This is a local implementation of [`ChainOracle`].
+#[derive(Debug, Clone, PartialEq)]
+pub struct LocalChain {
+    tip: CheckPoint,
+}
+
+impl ChainOracle for LocalChain {
+    type Error = Infallible;
+
+    fn is_block_in_chain(
+        &self,
+        block: BlockId,
+        chain_tip: BlockId,
+    ) -> Result<Option<bool>, Self::Error> {
+        let chain_tip_cp = match self.tip.get(chain_tip.height) {
+            // we can only determine whether `block` is in chain of `chain_tip` if `chain_tip` can
+            // be identified in chain
+            Some(cp) if cp.hash() == chain_tip.hash => cp,
+            _ => return Ok(None),
+        };
+        match chain_tip_cp.get(block.height) {
+            Some(cp) => Ok(Some(cp.hash() == block.hash)),
+            None => Ok(None),
+        }
+    }
+
+    fn get_chain_tip(&self) -> Result<BlockId, Self::Error> {
+        Ok(self.tip.block_id())
+    }
+}
+
+impl LocalChain {
+    /// Get the genesis hash.
+    pub fn genesis_hash(&self) -> BlockHash {
+        self.tip.get(0).expect("genesis must exist").hash()
+    }
+
+    /// Construct [`LocalChain`] from genesis `hash`.
+    #[must_use]
+    pub fn from_genesis_hash(hash: BlockHash) -> (Self, ChangeSet) {
+        let height = 0;
+        let chain = Self {
+            tip: CheckPoint::new(BlockId { height, hash }),
+        };
+        let changeset = chain.initial_changeset();
+        (chain, changeset)
+    }
+
+    /// Construct a [`LocalChain`] from an initial `changeset`.
+    pub fn from_changeset(changeset: ChangeSet) -> Result<Self, MissingGenesisError> {
+        let genesis_entry = changeset.get(&0).copied().flatten();
+        let genesis_hash = match genesis_entry {
+            Some(hash) => hash,
+            None => return Err(MissingGenesisError),
+        };
+
+        let (mut chain, _) = Self::from_genesis_hash(genesis_hash);
+        chain.apply_changeset(&changeset)?;
+
+        debug_assert!(chain._check_changeset_is_applied(&changeset));
+
+        Ok(chain)
+    }
+
+    /// Construct a [`LocalChain`] from a given `checkpoint` tip.
+    pub fn from_tip(tip: CheckPoint) -> Result<Self, MissingGenesisError> {
+        let genesis_cp = tip.iter().last().expect("must have at least one element");
+        if genesis_cp.height() != 0 {
+            return Err(MissingGenesisError);
+        }
+        Ok(Self { tip })
+    }
+
+    /// Constructs a [`LocalChain`] from a [`BTreeMap`] of height to [`BlockHash`].
+    ///
+    /// The [`BTreeMap`] enforces the height order. However, the caller must ensure the blocks are
+    /// all of the same chain.
+    pub fn from_blocks(blocks: BTreeMap<u32, BlockHash>) -> Result<Self, MissingGenesisError> {
+        if !blocks.contains_key(&0) {
+            return Err(MissingGenesisError);
+        }
+
+        let mut tip: Option<CheckPoint> = None;
+        for block in &blocks {
+            match tip {
+                Some(curr) => {
+                    tip = Some(
+                        curr.push(BlockId::from(block))
+                            .expect("BTreeMap is ordered"),
+                    )
+                }
+                None => tip = Some(CheckPoint::new(BlockId::from(block))),
+            }
+        }
+
+        Ok(Self {
+            tip: tip.expect("already checked to have genesis"),
+        })
+    }
+
+    /// Get the highest checkpoint.
+    pub fn tip(&self) -> CheckPoint {
+        self.tip.clone()
+    }
+
+    /// Applies the given `update` to the chain.
+    ///
+    /// The method returns [`ChangeSet`] on success. This represents the changes applied to `self`.
+    ///
+    /// There must be no ambiguity about which of the existing chain's blocks are still valid and
+    /// which are now invalid. That is, the new chain must implicitly connect to a definite block in
+    /// the existing chain and invalidate the block after it (if it exists) by including a block at
+    /// the same height but with a different hash to explicitly exclude it as a connection point.
+    ///
+    /// # Errors
+    ///
+    /// An error will occur if the update does not correctly connect with `self`.
+    ///
+    /// [module-level documentation]: crate::local_chain
+    pub fn apply_update(&mut self, update: CheckPoint) -> Result<ChangeSet, CannotConnectError> {
+        let (new_tip, changeset) = merge_chains(self.tip.clone(), update)?;
+        self.tip = new_tip;
+        self._check_changeset_is_applied(&changeset);
+        Ok(changeset)
+    }
+
+    /// Update the chain with a given [`Header`] at `height` which you claim is connected to a existing block in the chain.
+    ///
+    /// This is useful when you have a block header that you want to record as part of the chain but
+    /// don't necessarily know that the `prev_blockhash` is in the chain.
+    ///
+    /// This will usually insert two new [`BlockId`]s into the chain: the header's block and the
+    /// header's `prev_blockhash` block. `connected_to` must already be in the chain but is allowed
+    /// to be `prev_blockhash` (in which case only one new block id will be inserted).
+    /// To be successful, `connected_to` must be chosen carefully so that `LocalChain`'s [update
+    /// rules][`apply_update`] are satisfied.
+    ///
+    /// # Errors
+    ///
+    /// [`ApplyHeaderError::InconsistentBlocks`] occurs if the `connected_to` block and the
+    /// [`Header`] is inconsistent. For example, if the `connected_to` block is the same height as
+    /// `header` or `prev_blockhash`, but has a different block hash. Or if the `connected_to`
+    /// height is greater than the header's `height`.
+    ///
+    /// [`ApplyHeaderError::CannotConnect`] occurs if the internal call to [`apply_update`] fails.
+    ///
+    /// [`apply_update`]: Self::apply_update
+    pub fn apply_header_connected_to(
+        &mut self,
+        header: &Header,
+        height: u32,
+        connected_to: BlockId,
+    ) -> Result<ChangeSet, ApplyHeaderError> {
+        let this = BlockId {
+            height,
+            hash: header.block_hash(),
+        };
+        let prev = height.checked_sub(1).map(|prev_height| BlockId {
+            height: prev_height,
+            hash: header.prev_blockhash,
+        });
+        let conn = match connected_to {
+            // `connected_to` can be ignored if same as `this` or `prev` (duplicate)
+            conn if conn == this || Some(conn) == prev => None,
+            // this occurs if:
+            // - `connected_to` height is the same as `prev`, but different hash
+            // - `connected_to` height is the same as `this`, but different hash
+            // - `connected_to` height is greater than `this` (this is not allowed)
+            conn if conn.height >= height.saturating_sub(1) => {
+                return Err(ApplyHeaderError::InconsistentBlocks)
+            }
+            conn => Some(conn),
+        };
+
+        let update = CheckPoint::from_block_ids([conn, prev, Some(this)].into_iter().flatten())
+            .expect("block ids must be in order");
+
+        self.apply_update(update)
+            .map_err(ApplyHeaderError::CannotConnect)
+    }
+
+    /// Update the chain with a given [`Header`] connecting it with the previous block.
+    ///
+    /// This is a convenience method to call [`apply_header_connected_to`] with the `connected_to`
+    /// parameter being `height-1:prev_blockhash`. If there is no previous block (i.e. genesis), we
+    /// use the current block as `connected_to`.
+    ///
+    /// [`apply_header_connected_to`]: LocalChain::apply_header_connected_to
+    pub fn apply_header(
+        &mut self,
+        header: &Header,
+        height: u32,
+    ) -> Result<ChangeSet, CannotConnectError> {
+        let connected_to = match height.checked_sub(1) {
+            Some(prev_height) => BlockId {
+                height: prev_height,
+                hash: header.prev_blockhash,
+            },
+            None => BlockId {
+                height,
+                hash: header.block_hash(),
+            },
+        };
+        self.apply_header_connected_to(header, height, connected_to)
+            .map_err(|err| match err {
+                ApplyHeaderError::InconsistentBlocks => {
+                    unreachable!("connected_to is derived from the block so is always consistent")
+                }
+                ApplyHeaderError::CannotConnect(err) => err,
+            })
+    }
+
+    /// Apply the given `changeset`.
+    pub fn apply_changeset(&mut self, changeset: &ChangeSet) -> Result<(), MissingGenesisError> {
+        let old_tip = self.tip.clone();
+        let new_tip = old_tip.apply_changeset(changeset)?;
+        self.tip = new_tip;
+        debug_assert!(self._check_changeset_is_applied(changeset));
         Ok(())
     }
 
@@ -397,16 +508,16 @@ impl LocalChain {
     ///
     /// Replacing the block hash of an existing checkpoint will result in an error.
     pub fn insert_block(&mut self, block_id: BlockId) -> Result<ChangeSet, AlterCheckPointError> {
-        if let Some(&original_hash) = self.index.get(&block_id.height) {
+        if let Some(original_cp) = self.tip.get(block_id.height) {
+            let original_hash = original_cp.hash();
             if original_hash != block_id.hash {
                 return Err(AlterCheckPointError {
                     height: block_id.height,
                     original_hash,
                     update_hash: Some(block_id.hash),
                 });
-            } else {
-                return Ok(ChangeSet::default());
             }
+            return Ok(ChangeSet::default());
         }
 
         let mut changeset = ChangeSet::default();
@@ -420,21 +531,51 @@ impl LocalChain {
         Ok(changeset)
     }
 
-    /// Reindex the heights in the chain from (and including) `from` height
-    fn reindex(&mut self, from: u32) {
-        let _ = self.index.split_off(&from);
-        for cp in self.iter_checkpoints() {
-            if cp.height() < from {
+    /// Removes blocks from (and inclusive of) the given `block_id`.
+    ///
+    /// This will remove blocks with a height equal or greater than `block_id`, but only if
+    /// `block_id` exists in the chain.
+    ///
+    /// # Errors
+    ///
+    /// This will fail with [`MissingGenesisError`] if the caller attempts to disconnect from the
+    /// genesis block.
+    pub fn disconnect_from(&mut self, block_id: BlockId) -> Result<ChangeSet, MissingGenesisError> {
+        let mut remove_from = Option::<CheckPoint>::None;
+        let mut changeset = ChangeSet::default();
+        for cp in self.tip().iter() {
+            let cp_id = cp.block_id();
+            if cp_id.height < block_id.height {
                 break;
             }
-            self.index.insert(cp.height(), cp.hash());
+            changeset.insert(cp_id.height, None);
+            if cp_id == block_id {
+                remove_from = Some(cp);
+            }
         }
+        self.tip = match remove_from.map(|cp| cp.prev()) {
+            // The checkpoint below the earliest checkpoint to remove will be the new tip.
+            Some(Some(new_tip)) => new_tip,
+            // If there is no checkpoint below the earliest checkpoint to remove, it means the
+            // "earliest checkpoint to remove" is the genesis block. We disallow removing the
+            // genesis block.
+            Some(None) => return Err(MissingGenesisError),
+            // If there is nothing to remove, we return an empty changeset.
+            None => return Ok(ChangeSet::default()),
+        };
+        Ok(changeset)
     }
 
     /// Derives an initial [`ChangeSet`], meaning that it can be applied to an empty chain to
     /// recover the current chain.
     pub fn initial_changeset(&self) -> ChangeSet {
-        self.index.iter().map(|(k, v)| (*k, Some(*v))).collect()
+        self.tip
+            .iter()
+            .map(|cp| {
+                let block_id = cp.block_id();
+                (block_id.height, Some(block_id.hash))
+            })
+            .collect()
     }
 
     /// Iterate over checkpoints in descending height order.
@@ -444,28 +585,49 @@ impl LocalChain {
         }
     }
 
-    /// Get a reference to the internal index mapping the height to block hash.
-    pub fn blocks(&self) -> &BTreeMap<u32, BlockHash> {
-        &self.index
-    }
-
-    fn _check_index_is_consistent_with_tip(&self) -> bool {
-        let tip_history = self
-            .tip
-            .iter()
-            .map(|cp| (cp.height(), cp.hash()))
-            .collect::<BTreeMap<_, _>>();
-        self.index == tip_history
-    }
-
     fn _check_changeset_is_applied(&self, changeset: &ChangeSet) -> bool {
-        for (height, exp_hash) in changeset {
-            if self.index.get(height) != exp_hash.as_ref() {
-                return false;
+        let mut curr_cp = self.tip.clone();
+        for (height, exp_hash) in changeset.iter().rev() {
+            match curr_cp.get(*height) {
+                Some(query_cp) => {
+                    if query_cp.height() != *height || Some(query_cp.hash()) != *exp_hash {
+                        return false;
+                    }
+                    curr_cp = query_cp;
+                }
+                None => {
+                    if exp_hash.is_some() {
+                        return false;
+                    }
+                }
             }
         }
         true
     }
+
+    /// Get checkpoint at given `height` (if it exists).
+    ///
+    /// This is a shorthand for calling [`CheckPoint::get`] on the [`tip`].
+    ///
+    /// [`tip`]: LocalChain::tip
+    pub fn get(&self, height: u32) -> Option<CheckPoint> {
+        self.tip.get(height)
+    }
+
+    /// Iterate checkpoints over a height range.
+    ///
+    /// Note that we always iterate checkpoints in reverse height order (iteration starts at tip
+    /// height).
+    ///
+    /// This is a shorthand for calling [`CheckPoint::range`] on the [`tip`].
+    ///
+    /// [`tip`]: LocalChain::tip
+    pub fn range<R>(&self, range: R) -> impl Iterator<Item = CheckPoint>
+    where
+        R: RangeBounds<u32>,
+    {
+        self.tip.range(range)
+    }
 }
 
 /// An error which occurs when a [`LocalChain`] is constructed without a genesis checkpoint.
@@ -535,14 +697,41 @@ impl core::fmt::Display for CannotConnectError {
 #[cfg(feature = "std")]
 impl std::error::Error for CannotConnectError {}
 
+/// The error type for [`LocalChain::apply_header_connected_to`].
+#[derive(Debug, Clone, PartialEq)]
+pub enum ApplyHeaderError {
+    /// Occurs when `connected_to` block conflicts with either the current block or previous block.
+    InconsistentBlocks,
+    /// Occurs when the update cannot connect with the original chain.
+    CannotConnect(CannotConnectError),
+}
+
+impl core::fmt::Display for ApplyHeaderError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            ApplyHeaderError::InconsistentBlocks => write!(
+                f,
+                "the `connected_to` block conflicts with either the current or previous block"
+            ),
+            ApplyHeaderError::CannotConnect(err) => core::fmt::Display::fmt(err, f),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for ApplyHeaderError {}
+
+/// Applies `update_tip` onto `original_tip`.
+///
+/// On success, a tuple is returned `(changeset, can_replace)`. If `can_replace` is true, then the
+/// `update_tip` can replace the `original_tip`.
 fn merge_chains(
     original_tip: CheckPoint,
     update_tip: CheckPoint,
-    introduce_older_blocks: bool,
-) -> Result<ChangeSet, CannotConnectError> {
+) -> Result<(CheckPoint, ChangeSet), CannotConnectError> {
     let mut changeset = ChangeSet::default();
-    let mut orig = original_tip.into_iter();
-    let mut update = update_tip.into_iter();
+    let mut orig = original_tip.iter();
+    let mut update = update_tip.iter();
     let mut curr_orig = None;
     let mut curr_update = None;
     let mut prev_orig: Option<CheckPoint> = None;
@@ -551,6 +740,12 @@ fn merge_chains(
     let mut prev_orig_was_invalidated = false;
     let mut potentially_invalidated_heights = vec![];
 
+    // If we can, we want to return the update tip as the new tip because this allows checkpoints
+    // in multiple locations to keep the same `Arc` pointers when they are being updated from each
+    // other using this function. We can do this as long as long as the update contains every
+    // block's height of the original chain.
+    let mut is_update_height_superset_of_original = true;
+
     // To find the difference between the new chain and the original we iterate over both of them
     // from the tip backwards in tandem. We always dealing with the highest one from either chain
     // first and move to the next highest. The crucial logic is applied when they have blocks at the
@@ -576,6 +771,8 @@ fn merge_chains(
                 prev_orig_was_invalidated = false;
                 prev_orig = curr_orig.take();
 
+                is_update_height_superset_of_original = false;
+
                 // OPTIMIZATION: we have run out of update blocks so we don't need to continue
                 // iterating because there's no possibility of adding anything to changeset.
                 if u.is_none() {
@@ -598,12 +795,20 @@ fn merge_chains(
                     }
                     point_of_agreement_found = true;
                     prev_orig_was_invalidated = false;
-                    // OPTIMIZATION 1 -- If we know that older blocks cannot be introduced without
-                    // invalidation, we can break after finding the point of agreement.
                     // OPTIMIZATION 2 -- if we have the same underlying pointer at this point, we
                     // can guarantee that no older blocks are introduced.
-                    if !introduce_older_blocks || Arc::as_ptr(&o.0) == Arc::as_ptr(&u.0) {
-                        return Ok(changeset);
+                    if Arc::as_ptr(&o.0) == Arc::as_ptr(&u.0) {
+                        if is_update_height_superset_of_original {
+                            return Ok((update_tip, changeset));
+                        } else {
+                            let new_tip =
+                                original_tip.apply_changeset(&changeset).map_err(|_| {
+                                    CannotConnectError {
+                                        try_include_height: 0,
+                                    }
+                                })?;
+                            return Ok((new_tip, changeset));
+                        }
                     }
                 } else {
                     // We have an invalidation height so we set the height to the updated hash and
@@ -637,5 +842,10 @@ fn merge_chains(
         }
     }
 
-    Ok(changeset)
+    let new_tip = original_tip
+        .apply_changeset(&changeset)
+        .map_err(|_| CannotConnectError {
+            try_include_height: 0,
+        })?;
+    Ok((new_tip, changeset))
 }

crates/chain/src/spk_client.rs

@@ -0,0 +1,446 @@
+//! Helper types for spk-based blockchain clients.
+
+use crate::{
+    collections::{BTreeMap, HashMap},
+    local_chain::CheckPoint,
+    ConfirmationTimeHeightAnchor, TxGraph,
+};
+use alloc::{boxed::Box, sync::Arc, vec::Vec};
+use bitcoin::{OutPoint, Script, ScriptBuf, Transaction, Txid};
+use core::{fmt::Debug, marker::PhantomData, ops::RangeBounds};
+
+/// A cache of [`Arc`]-wrapped full transactions, identified by their [`Txid`]s.
+///
+/// This is used by the chain-source to avoid re-fetching full transactions.
+pub type TxCache = HashMap<Txid, Arc<Transaction>>;
+
+/// Data required to perform a spk-based blockchain client sync.
+///
+/// A client sync fetches relevant chain data for a known list of scripts, transaction ids and
+/// outpoints. The sync process also updates the chain from the given [`CheckPoint`].
+pub struct SyncRequest {
+    /// A checkpoint for the current chain [`LocalChain::tip`].
+    /// The sync process will return a new chain update that extends this tip.
+    ///
+    /// [`LocalChain::tip`]: crate::local_chain::LocalChain::tip
+    pub chain_tip: CheckPoint,
+    /// Cache of full transactions, so the chain-source can avoid re-fetching.
+    pub tx_cache: TxCache,
+    /// Transactions that spend from or to these indexed script pubkeys.
+    pub spks: Box<dyn ExactSizeIterator<Item = ScriptBuf> + Send>,
+    /// Transactions with these txids.
+    pub txids: Box<dyn ExactSizeIterator<Item = Txid> + Send>,
+    /// Transactions with these outpoints or spent from these outpoints.
+    pub outpoints: Box<dyn ExactSizeIterator<Item = OutPoint> + Send>,
+}
+
+impl SyncRequest {
+    /// Construct a new [`SyncRequest`] from a given `cp` tip.
+    pub fn from_chain_tip(cp: CheckPoint) -> Self {
+        Self {
+            chain_tip: cp,
+            tx_cache: TxCache::new(),
+            spks: Box::new(core::iter::empty()),
+            txids: Box::new(core::iter::empty()),
+            outpoints: Box::new(core::iter::empty()),
+        }
+    }
+
+    /// Add to the [`TxCache`] held by the request.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn cache_txs<T>(mut self, full_txs: impl IntoIterator<Item = (Txid, T)>) -> Self
+    where
+        T: Into<Arc<Transaction>>,
+    {
+        self.tx_cache = full_txs
+            .into_iter()
+            .map(|(txid, tx)| (txid, tx.into()))
+            .collect();
+        self
+    }
+
+    /// Add all transactions from [`TxGraph`] into the [`TxCache`].
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn cache_graph_txs<A>(self, graph: &TxGraph<A>) -> Self {
+        self.cache_txs(graph.full_txs().map(|tx_node| (tx_node.txid, tx_node.tx)))
+    }
+
+    /// Set the [`Script`]s that will be synced against.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn set_spks(
+        mut self,
+        spks: impl IntoIterator<IntoIter = impl ExactSizeIterator<Item = ScriptBuf> + Send + 'static>,
+    ) -> Self {
+        self.spks = Box::new(spks.into_iter());
+        self
+    }
+
+    /// Set the [`Txid`]s that will be synced against.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn set_txids(
+        mut self,
+        txids: impl IntoIterator<IntoIter = impl ExactSizeIterator<Item = Txid> + Send + 'static>,
+    ) -> Self {
+        self.txids = Box::new(txids.into_iter());
+        self
+    }
+
+    /// Set the [`OutPoint`]s that will be synced against.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn set_outpoints(
+        mut self,
+        outpoints: impl IntoIterator<
+            IntoIter = impl ExactSizeIterator<Item = OutPoint> + Send + 'static,
+        >,
+    ) -> Self {
+        self.outpoints = Box::new(outpoints.into_iter());
+        self
+    }
+
+    /// Chain on additional [`Script`]s that will be synced against.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn chain_spks(
+        mut self,
+        spks: impl IntoIterator<
+            IntoIter = impl ExactSizeIterator<Item = ScriptBuf> + Send + 'static,
+            Item = ScriptBuf,
+        >,
+    ) -> Self {
+        self.spks = Box::new(ExactSizeChain::new(self.spks, spks.into_iter()));
+        self
+    }
+
+    /// Chain on additional [`Txid`]s that will be synced against.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn chain_txids(
+        mut self,
+        txids: impl IntoIterator<
+            IntoIter = impl ExactSizeIterator<Item = Txid> + Send + 'static,
+            Item = Txid,
+        >,
+    ) -> Self {
+        self.txids = Box::new(ExactSizeChain::new(self.txids, txids.into_iter()));
+        self
+    }
+
+    /// Chain on additional [`OutPoint`]s that will be synced against.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn chain_outpoints(
+        mut self,
+        outpoints: impl IntoIterator<
+            IntoIter = impl ExactSizeIterator<Item = OutPoint> + Send + 'static,
+            Item = OutPoint,
+        >,
+    ) -> Self {
+        self.outpoints = Box::new(ExactSizeChain::new(self.outpoints, outpoints.into_iter()));
+        self
+    }
+
+    /// Add a closure that will be called for [`Script`]s previously added to this request.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn inspect_spks(
+        mut self,
+        mut inspect: impl FnMut(&Script) + Send + Sync + 'static,
+    ) -> Self {
+        self.spks = Box::new(self.spks.inspect(move |spk| inspect(spk)));
+        self
+    }
+
+    /// Add a closure that will be called for [`Txid`]s previously added to this request.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn inspect_txids(mut self, mut inspect: impl FnMut(&Txid) + Send + Sync + 'static) -> Self {
+        self.txids = Box::new(self.txids.inspect(move |txid| inspect(txid)));
+        self
+    }
+
+    /// Add a closure that will be called for [`OutPoint`]s previously added to this request.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn inspect_outpoints(
+        mut self,
+        mut inspect: impl FnMut(&OutPoint) + Send + Sync + 'static,
+    ) -> Self {
+        self.outpoints = Box::new(self.outpoints.inspect(move |op| inspect(op)));
+        self
+    }
+
+    /// Populate the request with revealed script pubkeys from `index` with the given `spk_range`.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[cfg(feature = "miniscript")]
+    #[must_use]
+    pub fn populate_with_revealed_spks<K: Clone + Ord + Debug + Send + Sync>(
+        self,
+        index: &crate::keychain::KeychainTxOutIndex<K>,
+        spk_range: impl RangeBounds<K>,
+    ) -> Self {
+        use alloc::borrow::ToOwned;
+        self.chain_spks(
+            index
+                .revealed_spks(spk_range)
+                .map(|(_, _, spk)| spk.to_owned())
+                .collect::<Vec<_>>(),
+        )
+    }
+}
+
+/// Data returned from a spk-based blockchain client sync.
+///
+/// See also [`SyncRequest`].
+pub struct SyncResult<A = ConfirmationTimeHeightAnchor> {
+    /// The update to apply to the receiving [`TxGraph`].
+    pub graph_update: TxGraph<A>,
+    /// The update to apply to the receiving [`LocalChain`](crate::local_chain::LocalChain).
+    pub chain_update: CheckPoint,
+}
+
+/// Data required to perform a spk-based blockchain client full scan.
+///
+/// A client full scan iterates through all the scripts for the given keychains, fetching relevant
+/// data until some stop gap number of scripts is found that have no data. This operation is
+/// generally only used when importing or restoring previously used keychains in which the list of
+/// used scripts is not known. The full scan process also updates the chain from the given [`CheckPoint`].
+pub struct FullScanRequest<K> {
+    /// A checkpoint for the current [`LocalChain::tip`].
+    /// The full scan process will return a new chain update that extends this tip.
+    ///
+    /// [`LocalChain::tip`]: crate::local_chain::LocalChain::tip
+    pub chain_tip: CheckPoint,
+    /// Cache of full transactions, so the chain-source can avoid re-fetching.
+    pub tx_cache: TxCache,
+    /// Iterators of script pubkeys indexed by the keychain index.
+    pub spks_by_keychain: BTreeMap<K, Box<dyn Iterator<Item = (u32, ScriptBuf)> + Send>>,
+}
+
+impl<K: Ord + Clone> FullScanRequest<K> {
+    /// Construct a new [`FullScanRequest`] from a given `chain_tip`.
+    #[must_use]
+    pub fn from_chain_tip(chain_tip: CheckPoint) -> Self {
+        Self {
+            chain_tip,
+            tx_cache: TxCache::new(),
+            spks_by_keychain: BTreeMap::new(),
+        }
+    }
+
+    /// Add to the [`TxCache`] held by the request.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn cache_txs<T>(mut self, full_txs: impl IntoIterator<Item = (Txid, T)>) -> Self
+    where
+        T: Into<Arc<Transaction>>,
+    {
+        self.tx_cache = full_txs
+            .into_iter()
+            .map(|(txid, tx)| (txid, tx.into()))
+            .collect();
+        self
+    }
+
+    /// Add all transactions from [`TxGraph`] into the [`TxCache`].
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn cache_graph_txs<A>(self, graph: &TxGraph<A>) -> Self {
+        self.cache_txs(graph.full_txs().map(|tx_node| (tx_node.txid, tx_node.tx)))
+    }
+
+    /// Construct a new [`FullScanRequest`] from a given `chain_tip` and `index`.
+    ///
+    /// Unbounded script pubkey iterators for each keychain (`K`) are extracted using
+    /// [`KeychainTxOutIndex::all_unbounded_spk_iters`] and is used to populate the
+    /// [`FullScanRequest`].
+    ///
+    /// [`KeychainTxOutIndex::all_unbounded_spk_iters`]: crate::keychain::KeychainTxOutIndex::all_unbounded_spk_iters
+    #[cfg(feature = "miniscript")]
+    #[must_use]
+    pub fn from_keychain_txout_index(
+        chain_tip: CheckPoint,
+        index: &crate::keychain::KeychainTxOutIndex<K>,
+    ) -> Self
+    where
+        K: Debug,
+    {
+        let mut req = Self::from_chain_tip(chain_tip);
+        for (keychain, spks) in index.all_unbounded_spk_iters() {
+            req = req.set_spks_for_keychain(keychain, spks);
+        }
+        req
+    }
+
+    /// Set the [`Script`]s for a given `keychain`.
+    ///
+    /// This consumes the [`FullScanRequest`] and returns the updated one.
+    #[must_use]
+    pub fn set_spks_for_keychain(
+        mut self,
+        keychain: K,
+        spks: impl IntoIterator<IntoIter = impl Iterator<Item = (u32, ScriptBuf)> + Send + 'static>,
+    ) -> Self {
+        self.spks_by_keychain
+            .insert(keychain, Box::new(spks.into_iter()));
+        self
+    }
+
+    /// Chain on additional [`Script`]s that will be synced against.
+    ///
+    /// This consumes the [`FullScanRequest`] and returns the updated one.
+    #[must_use]
+    pub fn chain_spks_for_keychain(
+        mut self,
+        keychain: K,
+        spks: impl IntoIterator<IntoIter = impl Iterator<Item = (u32, ScriptBuf)> + Send + 'static>,
+    ) -> Self {
+        match self.spks_by_keychain.remove(&keychain) {
+            // clippy here suggests to remove `into_iter` from `spks.into_iter()`, but doing so
+            // results in a compilation error
+            #[allow(clippy::useless_conversion)]
+            Some(keychain_spks) => self
+                .spks_by_keychain
+                .insert(keychain, Box::new(keychain_spks.chain(spks.into_iter()))),
+            None => self
+                .spks_by_keychain
+                .insert(keychain, Box::new(spks.into_iter())),
+        };
+        self
+    }
+
+    /// Add a closure that will be called for every [`Script`] previously added to any keychain in
+    /// this request.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn inspect_spks_for_all_keychains(
+        mut self,
+        inspect: impl FnMut(K, u32, &Script) + Send + Sync + Clone + 'static,
+    ) -> Self
+    where
+        K: Send + 'static,
+    {
+        for (keychain, spks) in core::mem::take(&mut self.spks_by_keychain) {
+            let mut inspect = inspect.clone();
+            self.spks_by_keychain.insert(
+                keychain.clone(),
+                Box::new(spks.inspect(move |(i, spk)| inspect(keychain.clone(), *i, spk))),
+            );
+        }
+        self
+    }
+
+    /// Add a closure that will be called for every [`Script`] previously added to a given
+    /// `keychain` in this request.
+    ///
+    /// This consumes the [`SyncRequest`] and returns the updated one.
+    #[must_use]
+    pub fn inspect_spks_for_keychain(
+        mut self,
+        keychain: K,
+        mut inspect: impl FnMut(u32, &Script) + Send + Sync + 'static,
+    ) -> Self
+    where
+        K: Send + 'static,
+    {
+        if let Some(spks) = self.spks_by_keychain.remove(&keychain) {
+            self.spks_by_keychain.insert(
+                keychain,
+                Box::new(spks.inspect(move |(i, spk)| inspect(*i, spk))),
+            );
+        }
+        self
+    }
+}
+
+/// Data returned from a spk-based blockchain client full scan.
+///
+/// See also [`FullScanRequest`].
+pub struct FullScanResult<K, A = ConfirmationTimeHeightAnchor> {
+    /// The update to apply to the receiving [`LocalChain`](crate::local_chain::LocalChain).
+    pub graph_update: TxGraph<A>,
+    /// The update to apply to the receiving [`TxGraph`].
+    pub chain_update: CheckPoint,
+    /// Last active indices for the corresponding keychains (`K`).
+    pub last_active_indices: BTreeMap<K, u32>,
+}
+
+/// A version of [`core::iter::Chain`] which can combine two [`ExactSizeIterator`]s to form a new
+/// [`ExactSizeIterator`].
+///
+/// The danger of this is explained in [the `ExactSizeIterator` docs]
+/// (https://doc.rust-lang.org/core/iter/trait.ExactSizeIterator.html#when-shouldnt-an-adapter-be-exactsizeiterator).
+/// This does not apply here since it would be impossible to scan an item count that overflows
+/// `usize` anyway.
+struct ExactSizeChain<A, B, I> {
+    a: Option<A>,
+    b: Option<B>,
+    i: PhantomData<I>,
+}
+
+impl<A, B, I> ExactSizeChain<A, B, I> {
+    fn new(a: A, b: B) -> Self {
+        ExactSizeChain {
+            a: Some(a),
+            b: Some(b),
+            i: PhantomData,
+        }
+    }
+}
+
+impl<A, B, I> Iterator for ExactSizeChain<A, B, I>
+where
+    A: Iterator<Item = I>,
+    B: Iterator<Item = I>,
+{
+    type Item = I;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if let Some(a) = &mut self.a {
+            let item = a.next();
+            if item.is_some() {
+                return item;
+            }
+            self.a = None;
+        }
+        if let Some(b) = &mut self.b {
+            let item = b.next();
+            if item.is_some() {
+                return item;
+            }
+            self.b = None;
+        }
+        None
+    }
+}
+
+impl<A, B, I> ExactSizeIterator for ExactSizeChain<A, B, I>
+where
+    A: ExactSizeIterator<Item = I>,
+    B: ExactSizeIterator<Item = I>,
+{
+    fn len(&self) -> usize {
+        let a_len = self.a.as_ref().map(|a| a.len()).unwrap_or(0);
+        let b_len = self.b.as_ref().map(|a| a.len()).unwrap_or(0);
+        a_len + b_len
+    }
+}

crates/chain/src/spk_iter.rs

@@ -43,18 +43,24 @@ impl<D> SpkIterator<D>
 where
     D: Borrow<Descriptor<DescriptorPublicKey>>,
 {
-    /// Creates a new script pubkey iterator starting at 0 from a descriptor.
+    /// Create a new script pubkey iterator from `descriptor`.
+    ///
+    /// This iterates from derivation index 0 and stops at index 0x7FFFFFFF (as specified in
+    /// BIP-32). Non-wildcard descriptors will only return one script pubkey at derivation index 0.
+    ///
+    /// Use [`new_with_range`](SpkIterator::new_with_range) to create an iterator with a specified
+    /// derivation index range.
     pub fn new(descriptor: D) -> Self {
         SpkIterator::new_with_range(descriptor, 0..=BIP32_MAX_INDEX)
     }
 
-    // Creates a new script pubkey iterator from a descriptor with a given range.
-    // If the descriptor doesn't have a wildcard, we shorten whichever range you pass in
-    // to have length <= 1. This means that if you pass in 0..0 or 0..1 the range will
-    // remain the same, but if you pass in 0..10, we'll shorten it to 0..1
-    // Also note that if the descriptor doesn't have a wildcard, passing in a range starting
-    // from n > 0, will return an empty iterator.
-    pub(crate) fn new_with_range<R>(descriptor: D, range: R) -> Self
+    /// Create a new script pubkey iterator from `descriptor` and a given `range`.
+    ///
+    /// Non-wildcard descriptors will only emit a single script pubkey (at derivation index 0).
+    /// Wildcard descriptors have an end-bound of 0x7FFFFFFF (inclusive).
+    ///
+    /// Refer to [`new`](SpkIterator::new) for more.
+    pub fn new_with_range<R>(descriptor: D, range: R) -> Self
     where
         R: RangeBounds<u32>,
     {
@@ -73,13 +79,6 @@ where
         // Because `end` is exclusive, we want the maximum value to be BIP32_MAX_INDEX + 1.
         end = end.min(BIP32_MAX_INDEX + 1);
 
-        if !descriptor.borrow().has_wildcard() {
-            // The length of the range should be at most 1
-            if end != start {
-                end = start + 1;
-            }
-        }
-
         Self {
             next_index: start,
             end,
@@ -87,6 +86,11 @@ where
             secp: Secp256k1::verification_only(),
         }
     }
+
+    /// Get a reference to the internal descriptor.
+    pub fn descriptor(&self) -> &D {
+        &self.descriptor
+    }
 }
 
 impl<D> Iterator for SpkIterator<D>
@@ -148,14 +152,14 @@ mod test {
         Descriptor<DescriptorPublicKey>,
         Descriptor<DescriptorPublicKey>,
     ) {
-        let mut txout_index = KeychainTxOutIndex::<TestKeychain>::default();
+        let mut txout_index = KeychainTxOutIndex::<TestKeychain>::new(0);
 
         let secp = Secp256k1::signing_only();
         let (external_descriptor,_) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/0/*)").unwrap();
         let (internal_descriptor,_) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/1/*)").unwrap();
 
-        txout_index.add_keychain(TestKeychain::External, external_descriptor.clone());
-        txout_index.add_keychain(TestKeychain::Internal, internal_descriptor.clone());
+        let _ = txout_index.insert_descriptor(TestKeychain::External, external_descriptor.clone());
+        let _ = txout_index.insert_descriptor(TestKeychain::Internal, internal_descriptor.clone());
 
         (txout_index, external_descriptor, internal_descriptor)
     }
@@ -245,18 +249,19 @@ mod test {
             SpkIterator::new_with_range(&no_wildcard_descriptor, 1..=2).next(),
             None
         );
-    }
-
-    // The following dummy traits were created to test if SpkIterator is working properly.
-    trait TestSendStatic: Send + 'static {
-        fn test(&self) -> u32 {
-            20
-        }
-    }
-
-    impl TestSendStatic for SpkIterator<Descriptor<DescriptorPublicKey>> {
-        fn test(&self) -> u32 {
-            20
-        }
+        assert_eq!(
+            SpkIterator::new_with_range(&no_wildcard_descriptor, 10..11).next(),
+            None
+        );
+        assert_eq!(
+            SpkIterator::new_with_range(&no_wildcard_descriptor, 10..=10).next(),
+            None
+        );
     }
 }
+
+#[test]
+fn spk_iterator_is_send_and_static() {
+    fn is_send_and_static<A: Send + 'static>() {}
+    is_send_and_static::<SpkIterator<Descriptor<DescriptorPublicKey>>>()
+}

crates/chain/src/spk_txout_index.rs

@@ -4,7 +4,7 @@ use crate::{
     collections::{hash_map::Entry, BTreeMap, BTreeSet, HashMap},
     indexed_tx_graph::Indexer,
 };
-use bitcoin::{self, OutPoint, Script, ScriptBuf, Transaction, TxOut, Txid};
+use bitcoin::{Amount, OutPoint, Script, ScriptBuf, SignedAmount, Transaction, TxOut, Txid};
 
 /// An index storing [`TxOut`]s that have a script pubkey that matches those in a list.
 ///
@@ -168,9 +168,7 @@ impl<I: Clone + Ord> SpkTxOutIndex<I> {
     ///
     /// Returns `None` if the `TxOut` hasn't been scanned or if nothing matching was found there.
     pub fn txout(&self, outpoint: OutPoint) -> Option<(&I, &TxOut)> {
-        self.txouts
-            .get(&outpoint)
-            .map(|(spk_i, txout)| (spk_i, txout))
+        self.txouts.get(&outpoint).map(|v| (&v.0, &v.1))
     }
 
     /// Returns the script that has been inserted at the `index`.
@@ -217,7 +215,7 @@ impl<I: Clone + Ord> SpkTxOutIndex<I> {
     /// let unused_change_spks =
     ///     txout_index.unused_spks((change_index, u32::MIN)..(change_index, u32::MAX));
     /// ```
-    pub fn unused_spks<R>(&self, range: R) -> impl DoubleEndedIterator<Item = (&I, &Script)>
+    pub fn unused_spks<R>(&self, range: R) -> impl DoubleEndedIterator<Item = (&I, &Script)> + Clone
     where
         R: RangeBounds<I>,
     {
@@ -231,7 +229,7 @@ impl<I: Clone + Ord> SpkTxOutIndex<I> {
     /// Here, "unused" means that after the script pubkey was stored in the index, the index has
     /// never scanned a transaction output with it.
     pub fn is_used(&self, index: &I) -> bool {
-        self.unused.get(index).is_none()
+        !self.unused.contains(index)
     }
 
     /// Marks the script pubkey at `index` as used even though it hasn't seen an output spending to it.
@@ -272,37 +270,45 @@ impl<I: Clone + Ord> SpkTxOutIndex<I> {
         self.spk_indices.get(script)
     }
 
-    /// Computes total input value going from script pubkeys in the index (sent) and the total output
-    /// value going to script pubkeys in the index (received) in `tx`. For the `sent` to be computed
-    /// correctly, the output being spent must have already been scanned by the index. Calculating
-    /// received just uses the [`Transaction`] outputs directly, so it will be correct even if it has
-    /// not been scanned.
-    pub fn sent_and_received(&self, tx: &Transaction) -> (u64, u64) {
-        let mut sent = 0;
-        let mut received = 0;
+    /// Computes the total value transfer effect `tx` has on the script pubkeys in `range`. Value is
+    /// *sent* when a script pubkey in the `range` is on an input and *received* when it is on an
+    /// output. For `sent` to be computed correctly, the output being spent must have already been
+    /// scanned by the index. Calculating received just uses the [`Transaction`] outputs directly,
+    /// so it will be correct even if it has not been scanned.
+    pub fn sent_and_received(
+        &self,
+        tx: &Transaction,
+        range: impl RangeBounds<I>,
+    ) -> (Amount, Amount) {
+        let mut sent = Amount::ZERO;
+        let mut received = Amount::ZERO;
 
         for txin in &tx.input {
-            if let Some((_, txout)) = self.txout(txin.previous_output) {
-                sent += txout.value;
+            if let Some((index, txout)) = self.txout(txin.previous_output) {
+                if range.contains(index) {
+                    sent += txout.value;
+                }
             }
         }
         for txout in &tx.output {
-            if self.index_of_spk(&txout.script_pubkey).is_some() {
-                received += txout.value;
+            if let Some(index) = self.index_of_spk(&txout.script_pubkey) {
+                if range.contains(index) {
+                    received += txout.value;
+                }
             }
         }
 
         (sent, received)
     }
 
-    /// Computes the net value that this transaction gives to the script pubkeys in the index and
-    /// *takes* from the transaction outputs in the index. Shorthand for calling
-    /// [`sent_and_received`] and subtracting sent from received.
+    /// Computes the net value transfer effect of `tx` on the script pubkeys in `range`. Shorthand
+    /// for calling [`sent_and_received`] and subtracting sent from received.
     ///
     /// [`sent_and_received`]: Self::sent_and_received
-    pub fn net_value(&self, tx: &Transaction) -> i64 {
-        let (sent, received) = self.sent_and_received(tx);
-        received as i64 - sent as i64
+    pub fn net_value(&self, tx: &Transaction, range: impl RangeBounds<I>) -> SignedAmount {
+        let (sent, received) = self.sent_and_received(tx, range);
+        received.to_signed().expect("valid `SignedAmount`")
+            - sent.to_signed().expect("valid `SignedAmount`")
     }
 
     /// Whether any of the inputs of this transaction spend a txout tracked or whether any output

crates/chain/src/tx_data_traits.rs

@@ -5,21 +5,25 @@ use alloc::vec::Vec;
 
 /// Trait that "anchors" blockchain data to a specific block of height and hash.
 ///
-/// [`Anchor`] implementations must be [`Ord`] by the anchor block's [`BlockId`] first.
-///
-/// I.e. If transaction A is anchored in block B, then if block B is in the best chain, we can
+/// If transaction A is anchored in block B, and block B is in the best chain, we can
 /// assume that transaction A is also confirmed in the best chain. This does not necessarily mean
 /// that transaction A is confirmed in block B. It could also mean transaction A is confirmed in a
 /// parent block of B.
 ///
+/// Every [`Anchor`] implementation must contain a [`BlockId`] parameter, and must implement
+/// [`Ord`]. When implementing [`Ord`], the anchors' [`BlockId`]s should take precedence
+/// over other elements inside the [`Anchor`]s for comparison purposes, i.e., you should first
+/// compare the anchors' [`BlockId`]s and then care about the rest.
+///
+/// The example shows different types of anchors:
 /// ```
 /// # use bdk_chain::local_chain::LocalChain;
 /// # use bdk_chain::tx_graph::TxGraph;
 /// # use bdk_chain::BlockId;
 /// # use bdk_chain::ConfirmationHeightAnchor;
+/// # use bdk_chain::ConfirmationTimeHeightAnchor;
 /// # use bdk_chain::example_utils::*;
 /// # use bitcoin::hashes::Hash;
-///
 /// // Initialize the local chain with two blocks.
 /// let chain = LocalChain::from_blocks(
 ///     [
@@ -47,6 +51,7 @@ use alloc::vec::Vec;
 /// );
 ///
 /// // Insert `tx` into a `TxGraph` that uses `ConfirmationHeightAnchor` as the anchor type.
+/// // This anchor records the anchor block and the confirmation height of the transaction.
 /// // When a transaction is anchored with `ConfirmationHeightAnchor`, the anchor block and
 /// // confirmation block can be different. However, the confirmation block cannot be higher than
 /// // the anchor block and both blocks must be in the same chain for the anchor to be valid.
@@ -62,6 +67,25 @@ use alloc::vec::Vec;
 ///         confirmation_height: 1,
 ///     },
 /// );
+///
+/// // Insert `tx` into a `TxGraph` that uses `ConfirmationTimeHeightAnchor` as the anchor type.
+/// // This anchor records the anchor block, the confirmation height and time of the transaction.
+/// // When a transaction is anchored with `ConfirmationTimeHeightAnchor`, the anchor block and
+/// // confirmation block can be different. However, the confirmation block cannot be higher than
+/// // the anchor block and both blocks must be in the same chain for the anchor to be valid.
+/// let mut graph_c = TxGraph::<ConfirmationTimeHeightAnchor>::default();
+/// let _ = graph_c.insert_tx(tx.clone());
+/// graph_c.insert_anchor(
+///     tx.txid(),
+///     ConfirmationTimeHeightAnchor {
+///         anchor_block: BlockId {
+///             height: 2,
+///             hash: Hash::hash("third".as_bytes()),
+///         },
+///         confirmation_height: 1,
+///         confirmation_time: 123,
+///     },
+/// );
 /// ```
 pub trait Anchor: core::fmt::Debug + Clone + Eq + PartialOrd + Ord + core::hash::Hash {
     /// Returns the [`BlockId`] that the associated blockchain data is "anchored" in.
@@ -99,8 +123,10 @@ pub trait Append {
 }
 
 impl<K: Ord, V> Append for BTreeMap<K, V> {
-    fn append(&mut self, mut other: Self) {
-        BTreeMap::append(self, &mut other)
+    fn append(&mut self, other: Self) {
+        // We use `extend` instead of `BTreeMap::append` due to performance issues with `append`.
+        // Refer to https://github.com/rust-lang/rust/issues/34666#issuecomment-675658420
+        BTreeMap::extend(self, other)
     }
 
     fn is_empty(&self) -> bool {
@@ -109,8 +135,10 @@ impl<K: Ord, V> Append for BTreeMap<K, V> {
 }
 
 impl<T: Ord> Append for BTreeSet<T> {
-    fn append(&mut self, mut other: Self) {
-        BTreeSet::append(self, &mut other)
+    fn append(&mut self, other: Self) {
+        // We use `extend` instead of `BTreeMap::append` due to performance issues with `append`.
+        // Refer to https://github.com/rust-lang/rust/issues/34666#issuecomment-675658420
+        BTreeSet::extend(self, other)
     }
 
     fn is_empty(&self) -> bool {

crates/chain/src/tx_graph.rs

@@ -1,39 +1,75 @@
 //! Module for structures that store and traverse transactions.
 //!
-//! [`TxGraph`] is a monotone structure that inserts transactions and indexes the spends. The
-//! [`ChangeSet`] structure reports changes of [`TxGraph`] but can also be applied to a
-//! [`TxGraph`] as well. Lastly, [`TxDescendants`] is an [`Iterator`] that traverses descendants of
-//! a given transaction.
+//! [`TxGraph`] contains transactions and indexes them so you can easily traverse the graph of
+//! those transactions. `TxGraph` is *monotone* in that you can always insert a transaction -- it
+//! does not care whether that transaction is in the current best chain or whether it conflicts with
+//! any of the existing transactions or what order you insert the transactions. This means that you
+//! can always combine two [`TxGraph`]s together, without resulting in inconsistencies. Furthermore,
+//! there is currently no way to delete a transaction.
+//!
+//! Transactions can be either whole or partial (i.e., transactions for which we only know some
+//! outputs, which we usually call "floating outputs"; these are usually inserted using the
+//! [`insert_txout`] method.).
+//!
+//! The graph contains transactions in the form of [`TxNode`]s. Each node contains the txid, the
+//! transaction (whole or partial), the blocks that it is anchored to (see the [`Anchor`]
+//! documentation for more details), and the timestamp of the last time we saw the transaction as
+//! unconfirmed.
 //!
 //! Conflicting transactions are allowed to coexist within a [`TxGraph`]. This is useful for
-//! identifying and traversing conflicts and descendants of a given transaction.
+//! identifying and traversing conflicts and descendants of a given transaction. Some [`TxGraph`]
+//! methods only consider transactions that are "canonical" (i.e., in the best chain or in mempool).
+//! We decide which transactions are canonical based on the transaction's anchors and the
+//! `last_seen` (as unconfirmed) timestamp; see the [`try_get_chain_position`] documentation for
+//! more details.
+//!
+//! The [`ChangeSet`] reports changes made to a [`TxGraph`]; it can be used to either save to
+//! persistent storage, or to be applied to another [`TxGraph`].
+//!
+//! Lastly, you can use [`TxAncestors`]/[`TxDescendants`] to traverse ancestors and descendants of
+//! a given transaction, respectively.
 //!
 //! # Applying changes
 //!
-//! Methods that apply changes to [`TxGraph`] will return [`ChangeSet`].
-//! [`ChangeSet`] can be applied back to a [`TxGraph`] or be used to inform persistent storage
+//! Methods that change the state of [`TxGraph`] will return [`ChangeSet`]s.
+//! [`ChangeSet`]s can be applied back to a [`TxGraph`] or be used to inform persistent storage
 //! of the changes to [`TxGraph`].
 //!
+//! # Generics
+//!
+//! Anchors are represented as generics within `TxGraph<A>`. To make use of all functionality of the
+//! `TxGraph`, anchors (`A`) should implement [`Anchor`].
+//!
+//! Anchors are made generic so that different types of data can be stored with how a transaction is
+//! *anchored* to a given block. An example of this is storing a merkle proof of the transaction to
+//! the confirmation block - this can be done with a custom [`Anchor`] type. The minimal [`Anchor`]
+//! type would just be a [`BlockId`] which just represents the height and hash of the block which
+//! the transaction is contained in. Note that a transaction can be contained in multiple
+//! conflicting blocks (by nature of the Bitcoin network).
+//!
 //! ```
 //! # use bdk_chain::BlockId;
 //! # use bdk_chain::tx_graph::TxGraph;
 //! # use bdk_chain::example_utils::*;
 //! # use bitcoin::Transaction;
 //! # let tx_a = tx_from_hex(RAW_TX_1);
-//! let mut graph: TxGraph = TxGraph::default();
-//! let mut another_graph: TxGraph = TxGraph::default();
+//! let mut tx_graph: TxGraph = TxGraph::default();
 //!
 //! // insert a transaction
-//! let changeset = graph.insert_tx(tx_a);
+//! let changeset = tx_graph.insert_tx(tx_a);
 //!
-//! // the resulting changeset can be applied to another tx graph
-//! another_graph.apply_changeset(changeset);
+//! // We can restore the state of the `tx_graph` by applying all
+//! // the changesets obtained by mutating the original (the order doesn't matter).
+//! let mut restored_tx_graph: TxGraph = TxGraph::default();
+//! restored_tx_graph.apply_changeset(changeset);
+//!
+//! assert_eq!(tx_graph, restored_tx_graph);
 //! ```
 //!
-//! A [`TxGraph`] can also be updated with another [`TxGraph`].
+//! A [`TxGraph`] can also be updated with another [`TxGraph`] which merges them together.
 //!
 //! ```
-//! # use bdk_chain::BlockId;
+//! # use bdk_chain::{Append, BlockId};
 //! # use bdk_chain::tx_graph::TxGraph;
 //! # use bdk_chain::example_utils::*;
 //! # use bitcoin::Transaction;
@@ -49,14 +85,17 @@
 //! let changeset = graph.apply_update(update);
 //! assert!(changeset.is_empty());
 //! ```
+//! [`try_get_chain_position`]: TxGraph::try_get_chain_position
+//! [`insert_txout`]: TxGraph::insert_txout
 
 use crate::{
-    collections::*, keychain::Balance, local_chain::LocalChain, Anchor, Append, BlockId,
-    ChainOracle, ChainPosition, FullTxOut,
+    collections::*, keychain::Balance, Anchor, Append, BlockId, ChainOracle, ChainPosition,
+    FullTxOut,
 };
 use alloc::collections::vec_deque::VecDeque;
+use alloc::sync::Arc;
 use alloc::vec::Vec;
-use bitcoin::{OutPoint, Script, Transaction, TxOut, Txid};
+use bitcoin::{Amount, OutPoint, Script, Transaction, TxOut, Txid};
 use core::fmt::{self, Formatter};
 use core::{
     convert::Infallible,
@@ -91,13 +130,13 @@ impl<A> Default for TxGraph<A> {
     }
 }
 
-/// An outward-facing view of a (transaction) node in the [`TxGraph`].
+/// A transaction node in the [`TxGraph`].
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub struct TxNode<'a, T, A> {
     /// Txid of the transaction.
     pub txid: Txid,
     /// A partial or full representation of the transaction.
-    pub tx: &'a T,
+    pub tx: T,
     /// The blocks that the transaction is "anchored" in.
     pub anchors: &'a BTreeSet<A>,
     /// The last-seen unix timestamp of the transaction as unconfirmed.
@@ -108,7 +147,7 @@ impl<'a, T, A> Deref for TxNode<'a, T, A> {
     type Target = T;
 
     fn deref(&self) -> &Self::Target {
-        self.tx
+        &self.tx
     }
 }
 
@@ -118,7 +157,7 @@ impl<'a, T, A> Deref for TxNode<'a, T, A> {
 /// outputs).
 #[derive(Clone, Debug, PartialEq)]
 enum TxNodeInternal {
-    Whole(Transaction),
+    Whole(Arc<Transaction>),
     Partial(BTreeMap<u32, TxOut>),
 }
 
@@ -128,7 +167,7 @@ impl Default for TxNodeInternal {
     }
 }
 
-/// An outwards-facing view of a transaction that is part of the *best chain*'s history.
+/// A transaction that is included in the chain, or is still in mempool.
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub struct CanonicalTx<'a, T, A> {
     /// How the transaction is observed as (confirmed or unconfirmed).
@@ -173,6 +212,7 @@ impl<A> TxGraph<A> {
     pub fn all_txouts(&self) -> impl Iterator<Item = (OutPoint, &TxOut)> {
         self.txs.iter().flat_map(|(txid, (tx, _, _))| match tx {
             TxNodeInternal::Whole(tx) => tx
+                .as_ref()
                 .output
                 .iter()
                 .enumerate()
@@ -204,13 +244,13 @@ impl<A> TxGraph<A> {
     }
 
     /// Iterate over all full transactions in the graph.
-    pub fn full_txs(&self) -> impl Iterator<Item = TxNode<'_, Transaction, A>> {
+    pub fn full_txs(&self) -> impl Iterator<Item = TxNode<'_, Arc<Transaction>, A>> {
         self.txs
             .iter()
             .filter_map(|(&txid, (tx, anchors, last_seen))| match tx {
                 TxNodeInternal::Whole(tx) => Some(TxNode {
                     txid,
-                    tx,
+                    tx: tx.clone(),
                     anchors,
                     last_seen_unconfirmed: *last_seen,
                 }),
@@ -223,16 +263,16 @@ impl<A> TxGraph<A> {
     /// Refer to [`get_txout`] for getting a specific [`TxOut`].
     ///
     /// [`get_txout`]: Self::get_txout
-    pub fn get_tx(&self, txid: Txid) -> Option<&Transaction> {
+    pub fn get_tx(&self, txid: Txid) -> Option<Arc<Transaction>> {
         self.get_tx_node(txid).map(|n| n.tx)
     }
 
     /// Get a transaction node by txid. This only returns `Some` for full transactions.
-    pub fn get_tx_node(&self, txid: Txid) -> Option<TxNode<'_, Transaction, A>> {
+    pub fn get_tx_node(&self, txid: Txid) -> Option<TxNode<'_, Arc<Transaction>, A>> {
         match &self.txs.get(&txid)? {
             (TxNodeInternal::Whole(tx), anchors, last_seen) => Some(TxNode {
                 txid,
-                tx,
+                tx: tx.clone(),
                 anchors,
                 last_seen_unconfirmed: *last_seen,
             }),
@@ -243,7 +283,7 @@ impl<A> TxGraph<A> {
     /// Obtains a single tx output (if any) at the specified outpoint.
     pub fn get_txout(&self, outpoint: OutPoint) -> Option<&TxOut> {
         match &self.txs.get(&outpoint.txid)?.0 {
-            TxNodeInternal::Whole(tx) => tx.output.get(outpoint.vout as usize),
+            TxNodeInternal::Whole(tx) => tx.as_ref().output.get(outpoint.vout as usize),
             TxNodeInternal::Partial(txouts) => txouts.get(&outpoint.vout),
         }
     }
@@ -254,6 +294,7 @@ impl<A> TxGraph<A> {
     pub fn tx_outputs(&self, txid: Txid) -> Option<BTreeMap<u32, &TxOut>> {
         Some(match &self.txs.get(&txid)?.0 {
             TxNodeInternal::Whole(tx) => tx
+                .as_ref()
                 .output
                 .iter()
                 .enumerate()
@@ -278,7 +319,7 @@ impl<A> TxGraph<A> {
     ///
     /// [`insert_txout`]: Self::insert_txout
     pub fn calculate_fee(&self, tx: &Transaction) -> Result<u64, CalculateFeeError> {
-        if tx.is_coin_base() {
+        if tx.is_coinbase() {
             return Ok(0);
         }
 
@@ -290,7 +331,7 @@ impl<A> TxGraph<A> {
                     (sum, missing_outpoints)
                 }
                 Some(txout) => {
-                    sum += txout.value as i64;
+                    sum += txout.value.to_sat() as i64;
                     (sum, missing_outpoints)
                 }
             },
@@ -302,7 +343,7 @@ impl<A> TxGraph<A> {
         let outputs_sum = tx
             .output
             .iter()
-            .map(|txout| txout.value as i64)
+            .map(|txout| txout.value.to_sat() as i64)
             .sum::<i64>();
 
         let fee = inputs_sum - outputs_sum;
@@ -315,7 +356,7 @@ impl<A> TxGraph<A> {
 
     /// The transactions spending from this output.
     ///
-    /// `TxGraph` allows conflicting transactions within the graph. Obviously the transactions in
+    /// [`TxGraph`] allows conflicting transactions within the graph. Obviously the transactions in
     /// the returned set will never be in the same active-chain.
     pub fn outspends(&self, outpoint: OutPoint) -> &HashSet<Txid> {
         self.spends.get(&outpoint).unwrap_or(&self.empty_outspends)
@@ -331,16 +372,15 @@ impl<A> TxGraph<A> {
         &self,
         txid: Txid,
     ) -> impl DoubleEndedIterator<Item = (u32, &HashSet<Txid>)> + '_ {
-        let start = OutPoint { txid, vout: 0 };
-        let end = OutPoint {
-            txid,
-            vout: u32::MAX,
-        };
+        let start = OutPoint::new(txid, 0);
+        let end = OutPoint::new(txid, u32::MAX);
         self.spends
             .range(start..=end)
             .map(|(outpoint, spends)| (outpoint.vout, spends))
     }
+}
 
+impl<A: Clone + Ord> TxGraph<A> {
     /// Creates an iterator that filters and maps ancestor transactions.
     ///
     /// The iterator starts with the ancestors of the supplied `tx` (ancestor transactions of `tx`
@@ -354,13 +394,10 @@ impl<A> TxGraph<A> {
     ///
     /// The supplied closure returns an `Option<T>`, allowing the caller to map each `Transaction`
     /// it visits and decide whether to visit ancestors.
-    pub fn walk_ancestors<'g, F, O>(
-        &'g self,
-        tx: &'g Transaction,
-        walk_map: F,
-    ) -> TxAncestors<'g, A, F>
+    pub fn walk_ancestors<'g, T, F, O>(&'g self, tx: T, walk_map: F) -> TxAncestors<'g, A, F>
     where
-        F: FnMut(usize, &'g Transaction) -> Option<O> + 'g,
+        T: Into<Arc<Transaction>>,
+        F: FnMut(usize, Arc<Transaction>) -> Option<O> + 'g,
     {
         TxAncestors::new_exclude_root(self, tx, walk_map)
     }
@@ -381,7 +418,9 @@ impl<A> TxGraph<A> {
     {
         TxDescendants::new_exclude_root(self, txid, walk_map)
     }
+}
 
+impl<A> TxGraph<A> {
     /// Creates an iterator that both filters and maps conflicting transactions (this includes
     /// descendants of directly-conflicting transactions, which are also considered conflicts).
     ///
@@ -394,7 +433,7 @@ impl<A> TxGraph<A> {
     where
         F: FnMut(usize, Txid) -> Option<O> + 'g,
     {
-        let txids = self.direct_conflitcs(tx).map(|(_, txid)| txid);
+        let txids = self.direct_conflicts(tx).map(|(_, txid)| txid);
         TxDescendants::from_multiple_include_root(self, txids, walk_map)
     }
 
@@ -405,7 +444,7 @@ impl<A> TxGraph<A> {
     /// Note that this only returns directly conflicting txids and won't include:
     /// - descendants of conflicting transactions (which are technically also conflicting)
     /// - transactions conflicting with the given transaction's ancestors
-    pub fn direct_conflitcs<'g>(
+    pub fn direct_conflicts<'g>(
         &'g self,
         tx: &'g Transaction,
     ) -> impl Iterator<Item = (usize, Txid)> + '_ {
@@ -430,6 +469,19 @@ impl<A> TxGraph<A> {
 }
 
 impl<A: Clone + Ord> TxGraph<A> {
+    /// Transform the [`TxGraph`] to have [`Anchor`]s of another type.
+    ///
+    /// This takes in a closure of signature `FnMut(A) -> A2` which is called for each [`Anchor`] to
+    /// transform it.
+    pub fn map_anchors<A2: Clone + Ord, F>(self, f: F) -> TxGraph<A2>
+    where
+        F: FnMut(A) -> A2,
+    {
+        let mut new_graph = TxGraph::<A2>::default();
+        new_graph.apply_changeset(self.initial_changeset().map_anchors(f));
+        new_graph
+    }
+
     /// Construct a new [`TxGraph`] from a list of transactions.
     pub fn new(txs: impl IntoIterator<Item = Transaction>) -> Self {
         let mut new = Self::default();
@@ -464,7 +516,8 @@ impl<A: Clone + Ord> TxGraph<A> {
     /// Inserts the given transaction into [`TxGraph`].
     ///
     /// The [`ChangeSet`] returned will be empty if `tx` already exists.
-    pub fn insert_tx(&mut self, tx: Transaction) -> ChangeSet<A> {
+    pub fn insert_tx<T: Into<Arc<Transaction>>>(&mut self, tx: T) -> ChangeSet<A> {
+        let tx = tx.into();
         let mut update = Self::default();
         update
             .txs
@@ -475,7 +528,7 @@ impl<A: Clone + Ord> TxGraph<A> {
     /// Batch insert unconfirmed transactions.
     ///
     /// Items of `txs` are tuples containing the transaction and a *last seen* timestamp. The
-    /// *last seen* communicates when the transaction is last seen in the mempool which is used for
+    /// *last seen* communicates when the transaction is last seen in mempool which is used for
     /// conflict-resolution (refer to [`TxGraph::insert_seen_at`] for details).
     pub fn batch_insert_unconfirmed(
         &mut self,
@@ -501,7 +554,11 @@ impl<A: Clone + Ord> TxGraph<A> {
 
     /// Inserts the given `seen_at` for `txid` into [`TxGraph`].
     ///
-    /// Note that [`TxGraph`] only keeps track of the latest `seen_at`.
+    /// Note that [`TxGraph`] only keeps track of the latest `seen_at`. To batch
+    /// update all unconfirmed transactions with the latest `seen_at`, see
+    /// [`update_last_seen_unconfirmed`].
+    ///
+    /// [`update_last_seen_unconfirmed`]: Self::update_last_seen_unconfirmed
     pub fn insert_seen_at(&mut self, txid: Txid, seen_at: u64) -> ChangeSet<A> {
         let mut update = Self::default();
         let (_, _, update_last_seen) = update.txs.entry(txid).or_default();
@@ -509,6 +566,65 @@ impl<A: Clone + Ord> TxGraph<A> {
         self.apply_update(update)
     }
 
+    /// Update the last seen time for all unconfirmed transactions.
+    ///
+    /// This method updates the last seen unconfirmed time for this [`TxGraph`] by inserting
+    /// the given `seen_at` for every transaction not yet anchored to a confirmed block,
+    /// and returns the [`ChangeSet`] after applying all updates to `self`.
+    ///
+    /// This is useful for keeping track of the latest time a transaction was seen
+    /// unconfirmed, which is important for evaluating transaction conflicts in the same
+    /// [`TxGraph`]. For details of how [`TxGraph`] resolves conflicts, see the docs for
+    /// [`try_get_chain_position`].
+    ///
+    /// A normal use of this method is to call it with the current system time. Although
+    /// block headers contain a timestamp, using the header time would be less effective
+    /// at tracking mempool transactions, because it can drift from actual clock time, plus
+    /// we may want to update a transaction's last seen time repeatedly between blocks.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// # use bdk_chain::example_utils::*;
+    /// # use std::time::UNIX_EPOCH;
+    /// # let tx = tx_from_hex(RAW_TX_1);
+    /// # let mut tx_graph = bdk_chain::TxGraph::<()>::new([tx]);
+    /// let now = std::time::SystemTime::now()
+    ///     .duration_since(UNIX_EPOCH)
+    ///     .expect("valid duration")
+    ///     .as_secs();
+    /// let changeset = tx_graph.update_last_seen_unconfirmed(now);
+    /// assert!(!changeset.last_seen.is_empty());
+    /// ```
+    ///
+    /// Note that [`TxGraph`] only keeps track of the latest `seen_at`, so the given time must
+    /// by strictly greater than what is currently stored for a transaction to have an effect.
+    /// To insert a last seen time for a single txid, see [`insert_seen_at`].
+    ///
+    /// [`insert_seen_at`]: Self::insert_seen_at
+    /// [`try_get_chain_position`]: Self::try_get_chain_position
+    pub fn update_last_seen_unconfirmed(&mut self, seen_at: u64) -> ChangeSet<A> {
+        let mut changeset = ChangeSet::default();
+        let unanchored_txs: Vec<Txid> = self
+            .txs
+            .iter()
+            .filter_map(
+                |(&txid, (_, anchors, _))| {
+                    if anchors.is_empty() {
+                        Some(txid)
+                    } else {
+                        None
+                    }
+                },
+            )
+            .collect();
+
+        for txid in unanchored_txs {
+            changeset.append(self.insert_seen_at(txid, seen_at));
+        }
+        changeset
+    }
+
     /// Extends this graph with another so that `self` becomes the union of the two sets of
     /// transactions.
     ///
@@ -527,7 +643,8 @@ impl<A: Clone + Ord> TxGraph<A> {
 
     /// Applies [`ChangeSet`] to [`TxGraph`].
     pub fn apply_changeset(&mut self, changeset: ChangeSet<A>) {
-        for tx in changeset.txs {
+        for wrapped_tx in changeset.txs {
+            let tx = wrapped_tx.as_ref();
             let txid = tx.txid();
 
             tx.input
@@ -542,27 +659,26 @@ impl<A: Clone + Ord> TxGraph<A> {
 
             match self.txs.get_mut(&txid) {
                 Some((tx_node @ TxNodeInternal::Partial(_), _, _)) => {
-                    *tx_node = TxNodeInternal::Whole(tx);
+                    *tx_node = TxNodeInternal::Whole(wrapped_tx.clone());
                 }
                 Some((TxNodeInternal::Whole(tx), _, _)) => {
                     debug_assert_eq!(
-                        tx.txid(),
+                        tx.as_ref().txid(),
                         txid,
                         "tx should produce txid that is same as key"
                     );
                 }
                 None => {
-                    self.txs
-                        .insert(txid, (TxNodeInternal::Whole(tx), BTreeSet::new(), 0));
+                    self.txs.insert(
+                        txid,
+                        (TxNodeInternal::Whole(wrapped_tx), BTreeSet::new(), 0),
+                    );
                 }
             }
         }
 
         for (outpoint, txout) in changeset.txouts {
-            let tx_entry = self
-                .txs
-                .entry(outpoint.txid)
-                .or_insert_with(Default::default);
+            let tx_entry = self.txs.entry(outpoint.txid).or_default();
 
             match tx_entry {
                 (TxNodeInternal::Whole(_), _, _) => { /* do nothing since we already have full tx */
@@ -575,13 +691,13 @@ impl<A: Clone + Ord> TxGraph<A> {
 
         for (anchor, txid) in changeset.anchors {
             if self.anchors.insert((anchor.clone(), txid)) {
-                let (_, anchors, _) = self.txs.entry(txid).or_insert_with(Default::default);
+                let (_, anchors, _) = self.txs.entry(txid).or_default();
                 anchors.insert(anchor);
             }
         }
 
         for (txid, new_last_seen) in changeset.last_seen {
-            let (_, _, last_seen) = self.txs.entry(txid).or_insert_with(Default::default);
+            let (_, _, last_seen) = self.txs.entry(txid).or_default();
             if new_last_seen > *last_seen {
                 *last_seen = new_last_seen;
             }
@@ -593,7 +709,7 @@ impl<A: Clone + Ord> TxGraph<A> {
     /// The [`ChangeSet`] would be the set difference between `update` and `self` (transactions that
     /// exist in `update` but not in `self`).
     pub(crate) fn determine_changeset(&self, update: TxGraph<A>) -> ChangeSet<A> {
-        let mut changeset = ChangeSet::default();
+        let mut changeset = ChangeSet::<A>::default();
 
         for (&txid, (update_tx_node, _, update_last_seen)) in &update.txs {
             let prev_last_seen: u64 = match (self.txs.get(&txid), update_tx_node) {
@@ -643,73 +759,22 @@ impl<A: Clone + Ord> TxGraph<A> {
 }
 
 impl<A: Anchor> TxGraph<A> {
-    /// Find missing block heights of `chain`.
-    ///
-    /// This works by scanning through anchors, and seeing whether the anchor block of the anchor
-    /// exists in the [`LocalChain`]. The returned iterator does not output duplicate heights.
-    pub fn missing_heights<'a>(&'a self, chain: &'a LocalChain) -> impl Iterator<Item = u32> + 'a {
-        // Map of txids to skip.
-        //
-        // Usually, if a height of a tx anchor is missing from the chain, we would want to return
-        // this height in the iterator. The exception is when the tx is confirmed in chain. All the
-        // other missing-height anchors of this tx can be skipped.
-        //
-        // * Some(true)  => skip all anchors of this txid
-        // * Some(false) => do not skip anchors of this txid
-        // * None        => we do not know whether we can skip this txid
-        let mut txids_to_skip = HashMap::<Txid, bool>::new();
-
-        // Keeps track of the last height emitted so we don't double up.
-        let mut last_height_emitted = Option::<u32>::None;
-
-        self.anchors
-            .iter()
-            .filter(move |(_, txid)| {
-                let skip = *txids_to_skip.entry(*txid).or_insert_with(|| {
-                    let tx_anchors = match self.txs.get(txid) {
-                        Some((_, anchors, _)) => anchors,
-                        None => return true,
-                    };
-                    let mut has_missing_height = false;
-                    for anchor_block in tx_anchors.iter().map(Anchor::anchor_block) {
-                        match chain.blocks().get(&anchor_block.height) {
-                            None => {
-                                has_missing_height = true;
-                                continue;
-                            }
-                            Some(chain_hash) => {
-                                if chain_hash == &anchor_block.hash {
-                                    return true;
-                                }
-                            }
-                        }
-                    }
-                    !has_missing_height
-                });
-                #[cfg(feature = "std")]
-                debug_assert!({
-                    println!("txid={} skip={}", txid, skip);
-                    true
-                });
-                !skip
-            })
-            .filter_map(move |(a, _)| {
-                let anchor_block = a.anchor_block();
-                if Some(anchor_block.height) != last_height_emitted
-                    && !chain.blocks().contains_key(&anchor_block.height)
-                {
-                    last_height_emitted = Some(anchor_block.height);
-                    Some(anchor_block.height)
-                } else {
-                    None
-                }
-            })
-    }
-
     /// Get the position of the transaction in `chain` with tip `chain_tip`.
     ///
-    /// If the given transaction of `txid` does not exist in the chain of `chain_tip`, `None` is
-    /// returned.
+    /// Chain data is fetched from `chain`, a [`ChainOracle`] implementation.
+    ///
+    /// This method returns `Ok(None)` if the transaction is not found in the chain, and no longer
+    /// belongs in the mempool. The following factors are used to approximate whether an
+    /// unconfirmed transaction exists in the mempool (not evicted):
+    ///
+    /// 1. Unconfirmed transactions that conflict with confirmed transactions are evicted.
+    /// 2. Unconfirmed transactions that spend from transactions that are evicted, are also
+    ///    evicted.
+    /// 3. Given two conflicting unconfirmed transactions, the transaction with the lower
+    ///    `last_seen_unconfirmed` parameter is evicted. A transaction's `last_seen_unconfirmed`
+    ///    parameter is the max of all it's descendants' `last_seen_unconfirmed` parameters. If the
+    ///    final `last_seen_unconfirmed`s are the same, the transaction with the lower `txid` (by
+    ///    lexicographical order) is evicted.
     ///
     /// # Error
     ///
@@ -735,17 +800,17 @@ impl<A: Anchor> TxGraph<A> {
             }
         }
 
-        // The tx is not anchored to a block which is in the best chain, which means that it
+        // The tx is not anchored to a block in the best chain, which means that it
         // might be in mempool, or it might have been dropped already.
         // Let's check conflicts to find out!
         let tx = match tx_node {
             TxNodeInternal::Whole(tx) => {
                 // A coinbase tx that is not anchored in the best chain cannot be unconfirmed and
                 // should always be filtered out.
-                if tx.is_coin_base() {
+                if tx.is_coinbase() {
                     return Ok(None);
                 }
-                tx
+                tx.clone()
             }
             TxNodeInternal::Partial(_) => {
                 // Partial transactions (outputs only) cannot have conflicts.
@@ -762,8 +827,8 @@ impl<A: Anchor> TxGraph<A> {
         // First of all, we retrieve all our ancestors. Since we're using `new_include_root`, the
         // resulting array will also include `tx`
         let unconfirmed_ancestor_txs =
-            TxAncestors::new_include_root(self, tx, |_, ancestor_tx: &Transaction| {
-                let tx_node = self.get_tx_node(ancestor_tx.txid())?;
+            TxAncestors::new_include_root(self, tx.clone(), |_, ancestor_tx: Arc<Transaction>| {
+                let tx_node = self.get_tx_node(ancestor_tx.as_ref().txid())?;
                 // We're filtering the ancestors to keep only the unconfirmed ones (= no anchors in
                 // the best chain)
                 for block in tx_node.anchors {
@@ -779,8 +844,10 @@ impl<A: Anchor> TxGraph<A> {
 
         // We determine our tx's last seen, which is the max between our last seen,
         // and our unconf descendants' last seen.
-        let unconfirmed_descendants_txs =
-            TxDescendants::new_include_root(self, tx.txid(), |_, descendant_txid: Txid| {
+        let unconfirmed_descendants_txs = TxDescendants::new_include_root(
+            self,
+            tx.as_ref().txid(),
+            |_, descendant_txid: Txid| {
                 let tx_node = self.get_tx_node(descendant_txid)?;
                 // We're filtering the ancestors to keep only the unconfirmed ones (= no anchors in
                 // the best chain)
@@ -792,8 +859,9 @@ impl<A: Anchor> TxGraph<A> {
                     }
                 }
                 Some(Ok(tx_node))
-            })
-            .collect::<Result<Vec<_>, C::Error>>()?;
+            },
+        )
+        .collect::<Result<Vec<_>, C::Error>>()?;
 
         let tx_last_seen = unconfirmed_descendants_txs
             .iter()
@@ -804,7 +872,8 @@ impl<A: Anchor> TxGraph<A> {
         // Now we traverse our ancestors and consider all their conflicts
         for tx_node in unconfirmed_ancestor_txs {
             // We retrieve all the transactions conflicting with this specific ancestor
-            let conflicting_txs = self.walk_conflicts(tx_node.tx, |_, txid| self.get_tx_node(txid));
+            let conflicting_txs =
+                self.walk_conflicts(tx_node.tx.as_ref(), |_, txid| self.get_tx_node(txid));
 
             // If a conflicting tx is in the best chain, or has `last_seen` higher than this ancestor, then
             // this tx cannot exist in the best chain
@@ -818,7 +887,7 @@ impl<A: Anchor> TxGraph<A> {
                     return Ok(None);
                 }
                 if conflicting_tx.last_seen_unconfirmed == *last_seen
-                    && conflicting_tx.txid() > tx.txid()
+                    && conflicting_tx.as_ref().txid() > tx.as_ref().txid()
                 {
                     // Conflicting tx has priority if txid of conflicting tx > txid of original tx
                     return Ok(None);
@@ -911,7 +980,7 @@ impl<A: Anchor> TxGraph<A> {
         &'a self,
         chain: &'a C,
         chain_tip: BlockId,
-    ) -> impl Iterator<Item = Result<CanonicalTx<'a, Transaction, A>, C::Error>> {
+    ) -> impl Iterator<Item = Result<CanonicalTx<'a, Arc<Transaction>, A>, C::Error>> {
         self.full_txs().filter_map(move |tx| {
             self.try_get_chain_position(chain, chain_tip, tx.txid)
                 .map(|v| {
@@ -933,7 +1002,7 @@ impl<A: Anchor> TxGraph<A> {
         &'a self,
         chain: &'a C,
         chain_tip: BlockId,
-    ) -> impl Iterator<Item = CanonicalTx<'a, Transaction, A>> {
+    ) -> impl Iterator<Item = CanonicalTx<'a, Arc<Transaction>, A>> {
         self.try_list_chain_txs(chain, chain_tip)
             .map(|r| r.expect("oracle is infallible"))
     }
@@ -945,7 +1014,8 @@ impl<A: Anchor> TxGraph<A> {
     /// (`OI`) for convenience. If `OI` is not necessary, the caller can use `()`, or
     /// [`Iterator::enumerate`] over a list of [`OutPoint`]s.
     ///
-    /// Floating outputs are ignored.
+    /// Floating outputs (i.e., outputs for which we don't have the full transaction in the graph)
+    /// are ignored.
     ///
     /// # Error
     ///
@@ -971,7 +1041,7 @@ impl<A: Anchor> TxGraph<A> {
                         None => return Ok(None),
                     };
 
-                    let txout = match tx_node.tx.output.get(op.vout as usize) {
+                    let txout = match tx_node.tx.as_ref().output.get(op.vout as usize) {
                         Some(txout) => txout.clone(),
                         None => return Ok(None),
                     };
@@ -993,7 +1063,7 @@ impl<A: Anchor> TxGraph<A> {
                             txout,
                             chain_position,
                             spent_by,
-                            is_on_coinbase: tx_node.tx.is_coin_base(),
+                            is_on_coinbase: tx_node.tx.is_coinbase(),
                         },
                     )))
                 },
@@ -1085,10 +1155,10 @@ impl<A: Anchor> TxGraph<A> {
         outpoints: impl IntoIterator<Item = (OI, OutPoint)>,
         mut trust_predicate: impl FnMut(&OI, &Script) -> bool,
     ) -> Result<Balance, C::Error> {
-        let mut immature = 0;
-        let mut trusted_pending = 0;
-        let mut untrusted_pending = 0;
-        let mut confirmed = 0;
+        let mut immature = Amount::ZERO;
+        let mut trusted_pending = Amount::ZERO;
+        let mut untrusted_pending = Amount::ZERO;
+        let mut confirmed = Amount::ZERO;
 
         for res in self.try_filter_chain_unspents(chain, chain_tip, outpoints) {
             let (spk_i, txout) = res?;
@@ -1136,9 +1206,9 @@ impl<A: Anchor> TxGraph<A> {
     }
 }
 
-/// A structure that represents changes to a [`TxGraph`].
+/// The [`ChangeSet`] represents changes to a [`TxGraph`].
 ///
-/// Since [`TxGraph`] is monotone "changeset" can only contain transactions to be added and
+/// Since [`TxGraph`] is monotone, the "changeset" can only contain transactions to be added and
 /// not removed.
 ///
 /// Refer to [module-level documentation] for more.
@@ -1159,7 +1229,7 @@ impl<A: Anchor> TxGraph<A> {
 #[must_use]
 pub struct ChangeSet<A = ()> {
     /// Added transactions.
-    pub txs: BTreeSet<Transaction>,
+    pub txs: BTreeSet<Arc<Transaction>>,
     /// Added txouts.
     pub txouts: BTreeMap<OutPoint, TxOut>,
     /// Added anchors.
@@ -1180,11 +1250,6 @@ impl<A> Default for ChangeSet<A> {
 }
 
 impl<A> ChangeSet<A> {
-    /// Returns true if the [`ChangeSet`] is empty (no transactions or txouts).
-    pub fn is_empty(&self) -> bool {
-        self.txs.is_empty() && self.txouts.is_empty()
-    }
-
     /// Iterates over all outpoints contained within [`ChangeSet`].
     pub fn txouts(&self) -> impl Iterator<Item = (OutPoint, &TxOut)> {
         self.txs
@@ -1202,8 +1267,6 @@ impl<A> ChangeSet<A> {
     ///
     /// This is useful if you want to find which heights you need to fetch data about in order to
     /// confirm or exclude these anchors.
-    ///
-    /// See also: [`TxGraph::missing_heights`]
     pub fn anchor_heights(&self) -> impl Iterator<Item = u32> + '_
     where
         A: Anchor,
@@ -1218,31 +1281,15 @@ impl<A> ChangeSet<A> {
                 !duplicate
             })
     }
-
-    /// Returns an iterator for the [`anchor_heights`] in this changeset that are not included in
-    /// `local_chain`. This tells you which heights you need to include in `local_chain` in order
-    /// for it to conclusively act as a [`ChainOracle`] for the transaction anchors this changeset
-    /// will add.
-    ///
-    /// [`ChainOracle`]: crate::ChainOracle
-    /// [`anchor_heights`]: Self::anchor_heights
-    pub fn missing_heights_from<'a>(
-        &'a self,
-        local_chain: &'a LocalChain,
-    ) -> impl Iterator<Item = u32> + 'a
-    where
-        A: Anchor,
-    {
-        self.anchor_heights()
-            .filter(move |height| !local_chain.blocks().contains_key(height))
-    }
 }
 
 impl<A: Ord> Append for ChangeSet<A> {
-    fn append(&mut self, mut other: Self) {
-        self.txs.append(&mut other.txs);
-        self.txouts.append(&mut other.txouts);
-        self.anchors.append(&mut other.anchors);
+    fn append(&mut self, other: Self) {
+        // We use `extend` instead of `BTreeMap::append` due to performance issues with `append`.
+        // Refer to https://github.com/rust-lang/rust/issues/34666#issuecomment-675658420
+        self.txs.extend(other.txs);
+        self.txouts.extend(other.txouts);
+        self.anchors.extend(other.anchors);
 
         // last_seen timestamps should only increase
         self.last_seen.extend(
@@ -1262,6 +1309,26 @@ impl<A: Ord> Append for ChangeSet<A> {
     }
 }
 
+impl<A: Ord> ChangeSet<A> {
+    /// Transform the [`ChangeSet`] to have [`Anchor`]s of another type.
+    ///
+    /// This takes in a closure of signature `FnMut(A) -> A2` which is called for each [`Anchor`] to
+    /// transform it.
+    pub fn map_anchors<A2: Ord, F>(self, mut f: F) -> ChangeSet<A2>
+    where
+        F: FnMut(A) -> A2,
+    {
+        ChangeSet {
+            txs: self.txs,
+            txouts: self.txouts,
+            anchors: BTreeSet::<(A2, Txid)>::from_iter(
+                self.anchors.into_iter().map(|(a, txid)| (f(a), txid)),
+            ),
+            last_seen: self.last_seen,
+        }
+    }
+}
+
 impl<A> AsRef<TxGraph<A>> for TxGraph<A> {
     fn as_ref(&self) -> &TxGraph<A> {
         self
@@ -1272,13 +1339,13 @@ impl<A> AsRef<TxGraph<A>> for TxGraph<A> {
 ///
 /// The iterator excludes partial transactions.
 ///
-/// This `struct` is created by the [`walk_ancestors`] method of [`TxGraph`].
+/// Returned by the [`walk_ancestors`] method of [`TxGraph`].
 ///
 /// [`walk_ancestors`]: TxGraph::walk_ancestors
 pub struct TxAncestors<'g, A, F> {
     graph: &'g TxGraph<A>,
     visited: HashSet<Txid>,
-    queue: VecDeque<(usize, &'g Transaction)>,
+    queue: VecDeque<(usize, Arc<Transaction>)>,
     filter_map: F,
 }
 
@@ -1286,13 +1353,13 @@ impl<'g, A, F> TxAncestors<'g, A, F> {
     /// Creates a `TxAncestors` that includes the starting `Transaction` when iterating.
     pub(crate) fn new_include_root(
         graph: &'g TxGraph<A>,
-        tx: &'g Transaction,
+        tx: impl Into<Arc<Transaction>>,
         filter_map: F,
     ) -> Self {
         Self {
             graph,
             visited: Default::default(),
-            queue: [(0, tx)].into(),
+            queue: [(0, tx.into())].into(),
             filter_map,
         }
     }
@@ -1300,7 +1367,7 @@ impl<'g, A, F> TxAncestors<'g, A, F> {
     /// Creates a `TxAncestors` that excludes the starting `Transaction` when iterating.
     pub(crate) fn new_exclude_root(
         graph: &'g TxGraph<A>,
-        tx: &'g Transaction,
+        tx: impl Into<Arc<Transaction>>,
         filter_map: F,
     ) -> Self {
         let mut ancestors = Self {
@@ -1309,7 +1376,7 @@ impl<'g, A, F> TxAncestors<'g, A, F> {
             queue: Default::default(),
             filter_map,
         };
-        ancestors.populate_queue(1, tx);
+        ancestors.populate_queue(1, tx.into());
         ancestors
     }
 
@@ -1322,12 +1389,13 @@ impl<'g, A, F> TxAncestors<'g, A, F> {
         filter_map: F,
     ) -> Self
     where
-        I: IntoIterator<Item = &'g Transaction>,
+        I: IntoIterator,
+        I::Item: Into<Arc<Transaction>>,
     {
         Self {
             graph,
             visited: Default::default(),
-            queue: txs.into_iter().map(|tx| (0, tx)).collect(),
+            queue: txs.into_iter().map(|tx| (0, tx.into())).collect(),
             filter_map,
         }
     }
@@ -1341,7 +1409,8 @@ impl<'g, A, F> TxAncestors<'g, A, F> {
         filter_map: F,
     ) -> Self
     where
-        I: IntoIterator<Item = &'g Transaction>,
+        I: IntoIterator,
+        I::Item: Into<Arc<Transaction>>,
     {
         let mut ancestors = Self {
             graph,
@@ -1350,12 +1419,12 @@ impl<'g, A, F> TxAncestors<'g, A, F> {
             filter_map,
         };
         for tx in txs {
-            ancestors.populate_queue(1, tx);
+            ancestors.populate_queue(1, tx.into());
         }
         ancestors
     }
 
-    fn populate_queue(&mut self, depth: usize, tx: &'g Transaction) {
+    fn populate_queue(&mut self, depth: usize, tx: Arc<Transaction>) {
         let ancestors = tx
             .input
             .iter()
@@ -1369,7 +1438,7 @@ impl<'g, A, F> TxAncestors<'g, A, F> {
 
 impl<'g, A, F, O> Iterator for TxAncestors<'g, A, F>
 where
-    F: FnMut(usize, &'g Transaction) -> Option<O>,
+    F: FnMut(usize, Arc<Transaction>) -> Option<O>,
 {
     type Item = O;
 
@@ -1378,7 +1447,7 @@ where
             // we have exhausted all paths when queue is empty
             let (ancestor_depth, tx) = self.queue.pop_front()?;
             // ignore paths when user filters them out
-            let item = match (self.filter_map)(ancestor_depth, tx) {
+            let item = match (self.filter_map)(ancestor_depth, tx.clone()) {
                 Some(item) => item,
                 None => continue,
             };
@@ -1390,7 +1459,7 @@ where
 
 /// An iterator that traverses transaction descendants.
 ///
-/// This `struct` is created by the [`walk_descendants`] method of [`TxGraph`].
+/// Returned by the [`walk_descendants`] method of [`TxGraph`].
 ///
 /// [`walk_descendants`]: TxGraph::walk_descendants
 pub struct TxDescendants<'g, A, F> {

crates/chain/tests/common/mod.rs

@@ -1,4 +1,7 @@
+#![cfg(feature = "miniscript")]
+
 mod tx_template;
+#[allow(unused_imports)]
 pub use tx_template::*;
 
 #[allow(unused_macros)]
@@ -31,12 +34,9 @@ macro_rules! local_chain {
 macro_rules! chain_update {
     [ $(($height:expr, $hash:expr)), * ] => {{
         #[allow(unused_mut)]
-        bdk_chain::local_chain::Update {
-            tip: bdk_chain::local_chain::LocalChain::from_blocks([$(($height, $hash).into()),*].into_iter().collect())
-                .expect("chain must have genesis block")
-                .tip(),
-            introduce_older_blocks: true,
-        }
+        bdk_chain::local_chain::LocalChain::from_blocks([$(($height, $hash).into()),*].into_iter().collect())
+            .expect("chain must have genesis block")
+            .tip()
     }};
 }
 
@@ -69,9 +69,21 @@ macro_rules! changeset {
 #[allow(unused)]
 pub fn new_tx(lt: u32) -> bitcoin::Transaction {
     bitcoin::Transaction {
-        version: 0x00,
+        version: bitcoin::transaction::Version::non_standard(0x00),
         lock_time: bitcoin::absolute::LockTime::from_consensus(lt),
         input: vec![],
         output: vec![],
     }
 }
+
+#[allow(unused)]
+pub const DESCRIPTORS: [&str; 7] = [
+    "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/0/*)",
+    "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/1/*)",
+    "wpkh([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/1/0/*)",
+    "tr(tprv8ZgxMBicQKsPd3krDUsBAmtnRsK3rb8u5yi1zhQgMhF1tR8MW7xfE4rnrbbsrbPR52e7rKapu6ztw1jXveJSCGHEriUGZV7mCe88duLp5pj/86'/1'/0'/0/*)",
+    "tr(tprv8ZgxMBicQKsPd3krDUsBAmtnRsK3rb8u5yi1zhQgMhF1tR8MW7xfE4rnrbbsrbPR52e7rKapu6ztw1jXveJSCGHEriUGZV7mCe88duLp5pj/86'/1'/0'/1/*)",
+    "wpkh(xprv9s21ZrQH143K4EXURwMHuLS469fFzZyXk7UUpdKfQwhoHcAiYTakpe8pMU2RiEdvrU9McyuE7YDoKcXkoAwEGoK53WBDnKKv2zZbb9BzttX/1/0/*)",
+    // non-wildcard
+    "wpkh([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/1/0)",
+];

crates/chain/tests/common/tx_template.rs

@@ -1,10 +1,12 @@
+#![cfg(feature = "miniscript")]
+
 use rand::distributions::{Alphanumeric, DistString};
 use std::collections::HashMap;
 
-use bdk_chain::{tx_graph::TxGraph, BlockId, SpkTxOutIndex};
+use bdk_chain::{tx_graph::TxGraph, Anchor, SpkTxOutIndex};
 use bitcoin::{
-    locktime::absolute::LockTime, secp256k1::Secp256k1, OutPoint, ScriptBuf, Sequence, Transaction,
-    TxIn, TxOut, Txid, Witness,
+    locktime::absolute::LockTime, secp256k1::Secp256k1, transaction, Amount, OutPoint, ScriptBuf,
+    Sequence, Transaction, TxIn, TxOut, Txid, Witness,
 };
 use miniscript::Descriptor;
 
@@ -49,11 +51,12 @@ impl TxOutTemplate {
 }
 
 #[allow(dead_code)]
-pub fn init_graph<'a>(
-    tx_templates: impl IntoIterator<Item = &'a TxTemplate<'a, BlockId>>,
-) -> (TxGraph<BlockId>, SpkTxOutIndex<u32>, HashMap<&'a str, Txid>) {
-    let (descriptor, _) = Descriptor::parse_descriptor(&Secp256k1::signing_only(), "tr(tprv8ZgxMBicQKsPd3krDUsBAmtnRsK3rb8u5yi1zhQgMhF1tR8MW7xfE4rnrbbsrbPR52e7rKapu6ztw1jXveJSCGHEriUGZV7mCe88duLp5pj/86'/1'/0'/0/*)").unwrap();
-    let mut graph = TxGraph::<BlockId>::default();
+pub fn init_graph<'a, A: Anchor + Clone + 'a>(
+    tx_templates: impl IntoIterator<Item = &'a TxTemplate<'a, A>>,
+) -> (TxGraph<A>, SpkTxOutIndex<u32>, HashMap<&'a str, Txid>) {
+    let (descriptor, _) =
+        Descriptor::parse_descriptor(&Secp256k1::signing_only(), super::DESCRIPTORS[2]).unwrap();
+    let mut graph = TxGraph::<A>::default();
     let mut spk_index = SpkTxOutIndex::default();
     (0..10).for_each(|index| {
         spk_index.insert_spk(
@@ -68,7 +71,7 @@ pub fn init_graph<'a>(
 
     for (bogus_txin_vout, tx_tmp) in tx_templates.into_iter().enumerate() {
         let tx = Transaction {
-            version: 0,
+            version: transaction::Version::non_standard(0),
             lock_time: LockTime::ZERO,
             input: tx_tmp
                 .inputs
@@ -111,11 +114,11 @@ pub fn init_graph<'a>(
                 .iter()
                 .map(|output| match &output.spk_index {
                     None => TxOut {
-                        value: output.value,
+                        value: Amount::from_sat(output.value),
                         script_pubkey: ScriptBuf::new(),
                     },
                     Some(index) => TxOut {
-                        value: output.value,
+                        value: Amount::from_sat(output.value),
                         script_pubkey: spk_index.spk_at_index(index).unwrap().to_owned(),
                     },
                 })
@@ -126,7 +129,7 @@ pub fn init_graph<'a>(
         spk_index.scan(&tx);
         let _ = graph.insert_tx(tx.clone());
         for anchor in tx_tmp.anchors.iter() {
-            let _ = graph.insert_anchor(tx.txid(), *anchor);
+            let _ = graph.insert_anchor(tx.txid(), anchor.clone());
         }
         if let Some(seen_at) = tx_tmp.last_seen {
             let _ = graph.insert_seen_at(tx.txid(), seen_at);

crates/chain/tests/test_indexed_tx_graph.rs

@@ -1,15 +1,20 @@
+#![cfg(feature = "miniscript")]
+
 #[macro_use]
 mod common;
 
-use std::collections::BTreeSet;
+use std::{collections::BTreeSet, sync::Arc};
 
+use crate::common::DESCRIPTORS;
 use bdk_chain::{
     indexed_tx_graph::{self, IndexedTxGraph},
     keychain::{self, Balance, KeychainTxOutIndex},
     local_chain::LocalChain,
-    tx_graph, BlockId, ChainPosition, ConfirmationHeightAnchor,
+    tx_graph, ChainPosition, ConfirmationHeightAnchor, DescriptorExt,
+};
+use bitcoin::{
+    secp256k1::Secp256k1, Amount, OutPoint, Script, ScriptBuf, Transaction, TxIn, TxOut,
 };
-use bitcoin::{secp256k1::Secp256k1, OutPoint, Script, ScriptBuf, Transaction, TxIn, TxOut};
 use miniscript::Descriptor;
 
 /// Ensure [`IndexedTxGraph::insert_relevant_txs`] can successfully index transactions NOT presented
@@ -21,24 +26,24 @@ use miniscript::Descriptor;
 /// agnostic.
 #[test]
 fn insert_relevant_txs() {
-    const DESCRIPTOR: &str = "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/0/*)";
-    let (descriptor, _) = Descriptor::parse_descriptor(&Secp256k1::signing_only(), DESCRIPTOR)
+    let (descriptor, _) = Descriptor::parse_descriptor(&Secp256k1::signing_only(), DESCRIPTORS[0])
         .expect("must be valid");
     let spk_0 = descriptor.at_derivation_index(0).unwrap().script_pubkey();
     let spk_1 = descriptor.at_derivation_index(9).unwrap().script_pubkey();
 
-    let mut graph = IndexedTxGraph::<ConfirmationHeightAnchor, KeychainTxOutIndex<()>>::default();
-    graph.index.add_keychain((), descriptor);
-    graph.index.set_lookahead(&(), 10);
+    let mut graph = IndexedTxGraph::<ConfirmationHeightAnchor, KeychainTxOutIndex<()>>::new(
+        KeychainTxOutIndex::new(10),
+    );
+    let _ = graph.index.insert_descriptor((), descriptor.clone());
 
     let tx_a = Transaction {
         output: vec![
             TxOut {
-                value: 10_000,
+                value: Amount::from_sat(10_000),
                 script_pubkey: spk_0,
             },
             TxOut {
-                value: 20_000,
+                value: Amount::from_sat(20_000),
                 script_pubkey: spk_1,
             },
         ],
@@ -65,10 +70,13 @@ fn insert_relevant_txs() {
 
     let changeset = indexed_tx_graph::ChangeSet {
         graph: tx_graph::ChangeSet {
-            txs: txs.clone().into(),
+            txs: txs.iter().cloned().map(Arc::new).collect(),
             ..Default::default()
         },
-        indexer: keychain::ChangeSet([((), 9_u32)].into()),
+        indexer: keychain::ChangeSet {
+            last_revealed: [(descriptor.descriptor_id(), 9_u32)].into(),
+            keychains_added: [].into(),
+        },
     };
 
     assert_eq!(
@@ -76,10 +84,18 @@ fn insert_relevant_txs() {
         changeset,
     );
 
-    assert_eq!(graph.initial_changeset(), changeset,);
+    // The initial changeset will also contain info about the keychain we added
+    let initial_changeset = indexed_tx_graph::ChangeSet {
+        graph: changeset.graph,
+        indexer: keychain::ChangeSet {
+            last_revealed: changeset.indexer.last_revealed,
+            keychains_added: [((), descriptor)].into(),
+        },
+    };
+
+    assert_eq!(graph.initial_changeset(), initial_changeset);
 }
 
-#[test]
 /// Ensure consistency IndexedTxGraph list_* and balance methods. These methods lists
 /// relevant txouts and utxos from the information fetched from a ChainOracle (here a LocalChain).
 ///
@@ -107,7 +123,7 @@ fn insert_relevant_txs() {
 ///
 /// Finally Add more blocks to local chain until tx1 coinbase maturity hits.
 /// Assert maturity at coinbase maturity inflection height. Block height 98 and 99.
-
+#[test]
 fn test_list_owned_txouts() {
     // Create Local chains
     let local_chain = LocalChain::from_blocks((0..150).map(|i| (i as u32, h!("random"))).collect())
@@ -115,15 +131,17 @@ fn test_list_owned_txouts() {
 
     // Initiate IndexedTxGraph
 
-    let (desc_1, _) = Descriptor::parse_descriptor(&Secp256k1::signing_only(), "tr(tprv8ZgxMBicQKsPd3krDUsBAmtnRsK3rb8u5yi1zhQgMhF1tR8MW7xfE4rnrbbsrbPR52e7rKapu6ztw1jXveJSCGHEriUGZV7mCe88duLp5pj/86'/1'/0'/0/*)").unwrap();
-    let (desc_2, _) = Descriptor::parse_descriptor(&Secp256k1::signing_only(), "tr(tprv8ZgxMBicQKsPd3krDUsBAmtnRsK3rb8u5yi1zhQgMhF1tR8MW7xfE4rnrbbsrbPR52e7rKapu6ztw1jXveJSCGHEriUGZV7mCe88duLp5pj/86'/1'/0'/1/*)").unwrap();
+    let (desc_1, _) =
+        Descriptor::parse_descriptor(&Secp256k1::signing_only(), common::DESCRIPTORS[2]).unwrap();
+    let (desc_2, _) =
+        Descriptor::parse_descriptor(&Secp256k1::signing_only(), common::DESCRIPTORS[3]).unwrap();
 
-    let mut graph =
-        IndexedTxGraph::<ConfirmationHeightAnchor, KeychainTxOutIndex<String>>::default();
+    let mut graph = IndexedTxGraph::<ConfirmationHeightAnchor, KeychainTxOutIndex<String>>::new(
+        KeychainTxOutIndex::new(10),
+    );
 
-    graph.index.add_keychain("keychain_1".into(), desc_1);
-    graph.index.add_keychain("keychain_2".into(), desc_2);
-    graph.index.set_lookahead_for_all(10);
+    let _ = graph.index.insert_descriptor("keychain_1".into(), desc_1);
+    let _ = graph.index.insert_descriptor("keychain_2".into(), desc_2);
 
     // Get trusted and untrusted addresses
 
@@ -133,14 +151,20 @@ fn test_list_owned_txouts() {
     {
         // we need to scope here to take immutanble reference of the graph
         for _ in 0..10 {
-            let ((_, script), _) = graph.index.reveal_next_spk(&"keychain_1".to_string());
+            let ((_, script), _) = graph
+                .index
+                .reveal_next_spk(&"keychain_1".to_string())
+                .unwrap();
             // TODO Assert indexes
             trusted_spks.push(script.to_owned());
         }
     }
     {
         for _ in 0..10 {
-            let ((_, script), _) = graph.index.reveal_next_spk(&"keychain_2".to_string());
+            let ((_, script), _) = graph
+                .index
+                .reveal_next_spk(&"keychain_2".to_string())
+                .unwrap();
             untrusted_spks.push(script.to_owned());
         }
     }
@@ -154,7 +178,7 @@ fn test_list_owned_txouts() {
             ..Default::default()
         }],
         output: vec![TxOut {
-            value: 70000,
+            value: Amount::from_sat(70000),
             script_pubkey: trusted_spks[0].to_owned(),
         }],
         ..common::new_tx(0)
@@ -163,7 +187,7 @@ fn test_list_owned_txouts() {
     // tx2 is an incoming transaction received at untrusted keychain at block 1.
     let tx2 = Transaction {
         output: vec![TxOut {
-            value: 30000,
+            value: Amount::from_sat(30000),
             script_pubkey: untrusted_spks[0].to_owned(),
         }],
         ..common::new_tx(0)
@@ -176,7 +200,7 @@ fn test_list_owned_txouts() {
             ..Default::default()
         }],
         output: vec![TxOut {
-            value: 10000,
+            value: Amount::from_sat(10000),
             script_pubkey: trusted_spks[1].to_owned(),
         }],
         ..common::new_tx(0)
@@ -185,7 +209,7 @@ fn test_list_owned_txouts() {
     // tx4 is an external transaction receiving at untrusted keychain, unconfirmed.
     let tx4 = Transaction {
         output: vec![TxOut {
-            value: 20000,
+            value: Amount::from_sat(20000),
             script_pubkey: untrusted_spks[1].to_owned(),
         }],
         ..common::new_tx(0)
@@ -194,7 +218,7 @@ fn test_list_owned_txouts() {
     // tx5 is spending tx3 and receiving change at trusted keychain, unconfirmed.
     let tx5 = Transaction {
         output: vec![TxOut {
-            value: 15000,
+            value: Amount::from_sat(15000),
             script_pubkey: trusted_spks[2].to_owned(),
         }],
         ..common::new_tx(0)
@@ -212,10 +236,8 @@ fn test_list_owned_txouts() {
             (
                 *tx,
                 local_chain
-                    .blocks()
-                    .get(&height)
-                    .cloned()
-                    .map(|hash| BlockId { height, hash })
+                    .get(height)
+                    .map(|cp| cp.block_id())
                     .map(|anchor_block| ConfirmationHeightAnchor {
                         anchor_block,
                         confirmation_height: anchor_block.height,
@@ -230,32 +252,23 @@ fn test_list_owned_txouts() {
         |height: u32,
          graph: &IndexedTxGraph<ConfirmationHeightAnchor, KeychainTxOutIndex<String>>| {
             let chain_tip = local_chain
-                .blocks()
-                .get(&height)
-                .map(|&hash| BlockId { height, hash })
+                .get(height)
+                .map(|cp| cp.block_id())
                 .unwrap_or_else(|| panic!("block must exist at {}", height));
             let txouts = graph
                 .graph()
-                .filter_chain_txouts(
-                    &local_chain,
-                    chain_tip,
-                    graph.index.outpoints().iter().cloned(),
-                )
+                .filter_chain_txouts(&local_chain, chain_tip, graph.index.outpoints())
                 .collect::<Vec<_>>();
 
             let utxos = graph
                 .graph()
-                .filter_chain_unspents(
-                    &local_chain,
-                    chain_tip,
-                    graph.index.outpoints().iter().cloned(),
-                )
+                .filter_chain_unspents(&local_chain, chain_tip, graph.index.outpoints())
                 .collect::<Vec<_>>();
 
             let balance = graph.graph().balance(
                 &local_chain,
                 chain_tip,
-                graph.index.outpoints().iter().cloned(),
+                graph.index.outpoints(),
                 |_, spk: &Script| trusted_spks.contains(&spk.to_owned()),
             );
 
@@ -342,10 +355,10 @@ fn test_list_owned_txouts() {
         assert_eq!(
             balance,
             Balance {
-                immature: 70000,          // immature coinbase
-                trusted_pending: 25000,   // tx3 + tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 0              // Nothing is confirmed yet
+                immature: Amount::from_sat(70000),          // immature coinbase
+                trusted_pending: Amount::from_sat(25000),   // tx3 + tx5
+                untrusted_pending: Amount::from_sat(20000), // tx4
+                confirmed: Amount::ZERO                     // Nothing is confirmed yet
             }
         );
     }
@@ -377,10 +390,10 @@ fn test_list_owned_txouts() {
         assert_eq!(
             balance,
             Balance {
-                immature: 70000,          // immature coinbase
-                trusted_pending: 25000,   // tx3 + tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 0              // Nothing is confirmed yet
+                immature: Amount::from_sat(70000),          // immature coinbase
+                trusted_pending: Amount::from_sat(25000),   // tx3 + tx5
+                untrusted_pending: Amount::from_sat(20000), // tx4
+                confirmed: Amount::ZERO                     // Nothing is confirmed yet
             }
         );
     }
@@ -409,10 +422,10 @@ fn test_list_owned_txouts() {
         assert_eq!(
             balance,
             Balance {
-                immature: 70000,          // immature coinbase
-                trusted_pending: 15000,   // tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 10000          // tx3 got confirmed
+                immature: Amount::from_sat(70000),          // immature coinbase
+                trusted_pending: Amount::from_sat(15000),   // tx5
+                untrusted_pending: Amount::from_sat(20000), // tx4
+                confirmed: Amount::from_sat(10000)          // tx3 got confirmed
             }
         );
     }
@@ -440,10 +453,10 @@ fn test_list_owned_txouts() {
         assert_eq!(
             balance,
             Balance {
-                immature: 70000,          // immature coinbase
-                trusted_pending: 15000,   // tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 10000          // tx1 got matured
+                immature: Amount::from_sat(70000),          // immature coinbase
+                trusted_pending: Amount::from_sat(15000),   // tx5
+                untrusted_pending: Amount::from_sat(20000), // tx4
+                confirmed: Amount::from_sat(10000)          // tx1 got matured
             }
         );
     }
@@ -456,10 +469,10 @@ fn test_list_owned_txouts() {
         assert_eq!(
             balance,
             Balance {
-                immature: 0,              // coinbase matured
-                trusted_pending: 15000,   // tx5
-                untrusted_pending: 20000, // tx4
-                confirmed: 80000          // tx1 + tx3
+                immature: Amount::ZERO,                     // coinbase matured
+                trusted_pending: Amount::from_sat(15000),   // tx5
+                untrusted_pending: Amount::from_sat(20000), // tx4
+                confirmed: Amount::from_sat(80000)          // tx1 + tx3
             }
         );
     }

crates/chain/tests/test_keychain_txout_index.rs

@@ -5,34 +5,39 @@ mod common;
 use bdk_chain::{
     collections::BTreeMap,
     indexed_tx_graph::Indexer,
-    keychain::{self, KeychainTxOutIndex},
-    Append,
+    keychain::{self, ChangeSet, KeychainTxOutIndex},
+    Append, DescriptorExt, DescriptorId,
 };
 
-use bitcoin::{secp256k1::Secp256k1, OutPoint, ScriptBuf, Transaction, TxOut};
+use bitcoin::{secp256k1::Secp256k1, Amount, OutPoint, ScriptBuf, Transaction, TxOut};
 use miniscript::{Descriptor, DescriptorPublicKey};
 
+use crate::common::DESCRIPTORS;
+
 #[derive(Clone, Debug, PartialEq, Eq, Ord, PartialOrd)]
 enum TestKeychain {
     External,
     Internal,
 }
 
-fn init_txout_index() -> (
-    bdk_chain::keychain::KeychainTxOutIndex<TestKeychain>,
-    Descriptor<DescriptorPublicKey>,
-    Descriptor<DescriptorPublicKey>,
-) {
-    let mut txout_index = bdk_chain::keychain::KeychainTxOutIndex::<TestKeychain>::default();
-
+fn parse_descriptor(descriptor: &str) -> Descriptor<DescriptorPublicKey> {
     let secp = bdk_chain::bitcoin::secp256k1::Secp256k1::signing_only();
-    let (external_descriptor,_) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/0/*)").unwrap();
-    let (internal_descriptor,_) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, "tr([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/1/*)").unwrap();
+    Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, descriptor)
+        .unwrap()
+        .0
+}
 
-    txout_index.add_keychain(TestKeychain::External, external_descriptor.clone());
-    txout_index.add_keychain(TestKeychain::Internal, internal_descriptor.clone());
+fn init_txout_index(
+    external_descriptor: Descriptor<DescriptorPublicKey>,
+    internal_descriptor: Descriptor<DescriptorPublicKey>,
+    lookahead: u32,
+) -> bdk_chain::keychain::KeychainTxOutIndex<TestKeychain> {
+    let mut txout_index = bdk_chain::keychain::KeychainTxOutIndex::<TestKeychain>::new(lookahead);
 
-    (txout_index, external_descriptor, internal_descriptor)
+    let _ = txout_index.insert_descriptor(TestKeychain::External, external_descriptor);
+    let _ = txout_index.insert_descriptor(TestKeychain::Internal, internal_descriptor);
+
+    txout_index
 }
 
 fn spk_at_index(descriptor: &Descriptor<DescriptorPublicKey>, index: u32) -> ScriptBuf {
@@ -42,119 +47,219 @@ fn spk_at_index(descriptor: &Descriptor<DescriptorPublicKey>, index: u32) -> Scr
         .script_pubkey()
 }
 
+// We create two empty changesets lhs and rhs, we then insert various descriptors with various
+// last_revealed, append rhs to lhs, and check that the result is consistent with these rules:
+// - Existing index doesn't update if the new index in `other` is lower than `self`.
+// - Existing index updates if the new index in `other` is higher than `self`.
+// - Existing index is unchanged if keychain doesn't exist in `other`.
+// - New keychain gets added if the keychain is in `other` but not in `self`.
+#[test]
+fn append_changesets_check_last_revealed() {
+    let secp = bitcoin::secp256k1::Secp256k1::signing_only();
+    let descriptor_ids: Vec<_> = DESCRIPTORS
+        .iter()
+        .take(4)
+        .map(|d| {
+            Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, d)
+                .unwrap()
+                .0
+                .descriptor_id()
+        })
+        .collect();
+
+    let mut lhs_di = BTreeMap::<DescriptorId, u32>::default();
+    let mut rhs_di = BTreeMap::<DescriptorId, u32>::default();
+    lhs_di.insert(descriptor_ids[0], 7);
+    lhs_di.insert(descriptor_ids[1], 0);
+    lhs_di.insert(descriptor_ids[2], 3);
+
+    rhs_di.insert(descriptor_ids[0], 3); // value less than lhs desc 0
+    rhs_di.insert(descriptor_ids[1], 5); // value more than lhs desc 1
+    lhs_di.insert(descriptor_ids[3], 4); // key doesn't exist in lhs
+
+    let mut lhs = ChangeSet {
+        keychains_added: BTreeMap::<(), _>::new(),
+        last_revealed: lhs_di,
+    };
+    let rhs = ChangeSet {
+        keychains_added: BTreeMap::<(), _>::new(),
+        last_revealed: rhs_di,
+    };
+    lhs.append(rhs);
+
+    // Existing index doesn't update if the new index in `other` is lower than `self`.
+    assert_eq!(lhs.last_revealed.get(&descriptor_ids[0]), Some(&7));
+    // Existing index updates if the new index in `other` is higher than `self`.
+    assert_eq!(lhs.last_revealed.get(&descriptor_ids[1]), Some(&5));
+    // Existing index is unchanged if keychain doesn't exist in `other`.
+    assert_eq!(lhs.last_revealed.get(&descriptor_ids[2]), Some(&3));
+    // New keychain gets added if the keychain is in `other` but not in `self`.
+    assert_eq!(lhs.last_revealed.get(&descriptor_ids[3]), Some(&4));
+}
+
+#[test]
+fn test_apply_changeset_with_different_descriptors_to_same_keychain() {
+    let external_descriptor = parse_descriptor(DESCRIPTORS[0]);
+    let internal_descriptor = parse_descriptor(DESCRIPTORS[1]);
+    let mut txout_index =
+        init_txout_index(external_descriptor.clone(), internal_descriptor.clone(), 0);
+    assert_eq!(
+        txout_index.keychains().collect::<Vec<_>>(),
+        vec![
+            (&TestKeychain::External, &external_descriptor),
+            (&TestKeychain::Internal, &internal_descriptor)
+        ]
+    );
+
+    let changeset = ChangeSet {
+        keychains_added: [(TestKeychain::External, internal_descriptor.clone())].into(),
+        last_revealed: [].into(),
+    };
+    txout_index.apply_changeset(changeset);
+
+    assert_eq!(
+        txout_index.keychains().collect::<Vec<_>>(),
+        vec![
+            (&TestKeychain::External, &internal_descriptor),
+            (&TestKeychain::Internal, &internal_descriptor)
+        ]
+    );
+
+    let changeset = ChangeSet {
+        keychains_added: [(TestKeychain::Internal, external_descriptor.clone())].into(),
+        last_revealed: [].into(),
+    };
+    txout_index.apply_changeset(changeset);
+
+    assert_eq!(
+        txout_index.keychains().collect::<Vec<_>>(),
+        vec![
+            (&TestKeychain::External, &internal_descriptor),
+            (&TestKeychain::Internal, &external_descriptor)
+        ]
+    );
+}
+
 #[test]
 fn test_set_all_derivation_indices() {
     use bdk_chain::indexed_tx_graph::Indexer;
 
-    let (mut txout_index, _, _) = init_txout_index();
+    let external_descriptor = parse_descriptor(DESCRIPTORS[0]);
+    let internal_descriptor = parse_descriptor(DESCRIPTORS[1]);
+    let mut txout_index =
+        init_txout_index(external_descriptor.clone(), internal_descriptor.clone(), 0);
     let derive_to: BTreeMap<_, _> =
         [(TestKeychain::External, 12), (TestKeychain::Internal, 24)].into();
+    let last_revealed: BTreeMap<_, _> = [
+        (external_descriptor.descriptor_id(), 12),
+        (internal_descriptor.descriptor_id(), 24),
+    ]
+    .into();
     assert_eq!(
-        txout_index.reveal_to_target_multi(&derive_to).1.as_inner(),
-        &derive_to
+        txout_index.reveal_to_target_multi(&derive_to).1,
+        ChangeSet {
+            keychains_added: BTreeMap::new(),
+            last_revealed: last_revealed.clone()
+        }
     );
-    assert_eq!(txout_index.last_revealed_indices(), &derive_to);
+    assert_eq!(txout_index.last_revealed_indices(), derive_to);
     assert_eq!(
         txout_index.reveal_to_target_multi(&derive_to).1,
         keychain::ChangeSet::default(),
         "no changes if we set to the same thing"
     );
-    assert_eq!(txout_index.initial_changeset().as_inner(), &derive_to);
+    assert_eq!(txout_index.initial_changeset().last_revealed, last_revealed);
 }
 
 #[test]
 fn test_lookahead() {
-    let (mut txout_index, external_desc, internal_desc) = init_txout_index();
-
-    // ensure it does not break anything if lookahead is set multiple times
-    (0..=10).for_each(|lookahead| txout_index.set_lookahead(&TestKeychain::External, lookahead));
-    (0..=20)
-        .filter(|v| v % 2 == 0)
-        .for_each(|lookahead| txout_index.set_lookahead(&TestKeychain::Internal, lookahead));
-
-    assert_eq!(txout_index.inner().all_spks().len(), 30);
+    let external_descriptor = parse_descriptor(DESCRIPTORS[0]);
+    let internal_descriptor = parse_descriptor(DESCRIPTORS[1]);
+    let mut txout_index =
+        init_txout_index(external_descriptor.clone(), internal_descriptor.clone(), 10);
 
     // given:
     // - external lookahead set to 10
-    // - internal lookahead set to 20
     // when:
     // - set external derivation index to value higher than last, but within the lookahead value
     // expect:
     // - scripts cached in spk_txout_index should increase correctly
     // - stored scripts of external keychain should be of expected counts
     for index in (0..20).skip_while(|i| i % 2 == 1) {
-        let (revealed_spks, revealed_changeset) =
-            txout_index.reveal_to_target(&TestKeychain::External, index);
+        let (revealed_spks, revealed_changeset) = txout_index
+            .reveal_to_target(&TestKeychain::External, index)
+            .unwrap();
         assert_eq!(
             revealed_spks.collect::<Vec<_>>(),
-            vec![(index, spk_at_index(&external_desc, index))],
+            vec![(index, spk_at_index(&external_descriptor, index))],
         );
         assert_eq!(
-            revealed_changeset.as_inner(),
-            &[(TestKeychain::External, index)].into()
+            &revealed_changeset.last_revealed,
+            &[(external_descriptor.descriptor_id(), index)].into()
         );
 
         assert_eq!(
             txout_index.inner().all_spks().len(),
             10 /* external lookahead */ +
-            20 /* internal lookahead */ +
+            10 /* internal lookahead */ +
             index as usize + 1 /* `derived` count */
         );
         assert_eq!(
             txout_index
-                .revealed_spks_of_keychain(&TestKeychain::External)
+                .revealed_keychain_spks(&TestKeychain::External)
                 .count(),
             index as usize + 1,
         );
         assert_eq!(
             txout_index
-                .revealed_spks_of_keychain(&TestKeychain::Internal)
+                .revealed_keychain_spks(&TestKeychain::Internal)
                 .count(),
             0,
         );
         assert_eq!(
             txout_index
-                .unused_spks_of_keychain(&TestKeychain::External)
+                .unused_keychain_spks(&TestKeychain::External)
                 .count(),
             index as usize + 1,
         );
         assert_eq!(
             txout_index
-                .unused_spks_of_keychain(&TestKeychain::Internal)
+                .unused_keychain_spks(&TestKeychain::Internal)
                 .count(),
             0,
         );
     }
 
     // given:
-    // - internal lookahead is 20
+    // - internal lookahead is 10
     // - internal derivation index is `None`
     // when:
     // - derivation index is set ahead of current derivation index + lookahead
     // expect:
     // - scripts cached in spk_txout_index should increase correctly, a.k.a. no scripts are skipped
-    let (revealed_spks, revealed_changeset) =
-        txout_index.reveal_to_target(&TestKeychain::Internal, 24);
+    let (revealed_spks, revealed_changeset) = txout_index
+        .reveal_to_target(&TestKeychain::Internal, 24)
+        .unwrap();
     assert_eq!(
         revealed_spks.collect::<Vec<_>>(),
         (0..=24)
-            .map(|index| (index, spk_at_index(&internal_desc, index)))
+            .map(|index| (index, spk_at_index(&internal_descriptor, index)))
             .collect::<Vec<_>>(),
     );
     assert_eq!(
-        revealed_changeset.as_inner(),
-        &[(TestKeychain::Internal, 24)].into()
+        &revealed_changeset.last_revealed,
+        &[(internal_descriptor.descriptor_id(), 24)].into()
     );
     assert_eq!(
         txout_index.inner().all_spks().len(),
         10 /* external lookahead */ +
-        20 /* internal lookahead */ +
+        10 /* internal lookahead */ +
         20 /* external stored index count */ +
         25 /* internal stored index count */
     );
     assert_eq!(
         txout_index
-            .revealed_spks_of_keychain(&TestKeychain::Internal)
+            .revealed_keychain_spks(&TestKeychain::Internal)
             .count(),
         25,
     );
@@ -179,18 +284,18 @@ fn test_lookahead() {
         let tx = Transaction {
             output: vec![
                 TxOut {
-                    script_pubkey: external_desc
+                    script_pubkey: external_descriptor
                         .at_derivation_index(external_index)
                         .unwrap()
                         .script_pubkey(),
-                    value: 10_000,
+                    value: Amount::from_sat(10_000),
                 },
                 TxOut {
-                    script_pubkey: internal_desc
+                    script_pubkey: internal_descriptor
                         .at_derivation_index(internal_index)
                         .unwrap()
                         .script_pubkey(),
-                    value: 10_000,
+                    value: Amount::from_sat(10_000),
                 },
             ],
             ..common::new_tx(external_index)
@@ -206,13 +311,13 @@ fn test_lookahead() {
         );
         assert_eq!(
             txout_index
-                .revealed_spks_of_keychain(&TestKeychain::External)
+                .revealed_keychain_spks(&TestKeychain::External)
                 .count(),
             last_external_index as usize + 1,
         );
         assert_eq!(
             txout_index
-                .revealed_spks_of_keychain(&TestKeychain::Internal)
+                .revealed_keychain_spks(&TestKeychain::Internal)
                 .count(),
             last_internal_index as usize + 1,
         );
@@ -226,15 +331,17 @@ fn test_lookahead() {
 // - last used index should change as expected
 #[test]
 fn test_scan_with_lookahead() {
-    let (mut txout_index, external_desc, _) = init_txout_index();
-    txout_index.set_lookahead_for_all(10);
+    let external_descriptor = parse_descriptor(DESCRIPTORS[0]);
+    let internal_descriptor = parse_descriptor(DESCRIPTORS[1]);
+    let mut txout_index =
+        init_txout_index(external_descriptor.clone(), internal_descriptor.clone(), 10);
 
     let spks: BTreeMap<u32, ScriptBuf> = [0, 10, 20, 30]
         .into_iter()
         .map(|i| {
             (
                 i,
-                external_desc
+                external_descriptor
                     .at_derivation_index(i)
                     .unwrap()
                     .script_pubkey(),
@@ -246,13 +353,13 @@ fn test_scan_with_lookahead() {
         let op = OutPoint::new(h!("fake tx"), spk_i);
         let txout = TxOut {
             script_pubkey: spk.clone(),
-            value: 0,
+            value: Amount::ZERO,
         };
 
         let changeset = txout_index.index_txout(op, &txout);
         assert_eq!(
-            changeset.as_inner(),
-            &[(TestKeychain::External, spk_i)].into()
+            &changeset.last_revealed,
+            &[(external_descriptor.descriptor_id(), spk_i)].into()
         );
         assert_eq!(
             txout_index.last_revealed_index(&TestKeychain::External),
@@ -265,14 +372,14 @@ fn test_scan_with_lookahead() {
     }
 
     // now try with index 41 (lookahead surpassed), we expect that the txout to not be indexed
-    let spk_41 = external_desc
+    let spk_41 = external_descriptor
         .at_derivation_index(41)
         .unwrap()
         .script_pubkey();
     let op = OutPoint::new(h!("fake tx"), 41);
     let txout = TxOut {
         script_pubkey: spk_41,
-        value: 0,
+        value: Amount::ZERO,
     };
     let changeset = txout_index.index_txout(op, &txout);
     assert!(changeset.is_empty());
@@ -281,11 +388,13 @@ fn test_scan_with_lookahead() {
 #[test]
 #[rustfmt::skip]
 fn test_wildcard_derivations() {
-    let (mut txout_index, external_desc, _) = init_txout_index();
-    let external_spk_0 = external_desc.at_derivation_index(0).unwrap().script_pubkey();
-    let external_spk_16 = external_desc.at_derivation_index(16).unwrap().script_pubkey();
-    let external_spk_26 = external_desc.at_derivation_index(26).unwrap().script_pubkey();
-    let external_spk_27 = external_desc.at_derivation_index(27).unwrap().script_pubkey();
+    let external_descriptor = parse_descriptor(DESCRIPTORS[0]);
+    let internal_descriptor = parse_descriptor(DESCRIPTORS[1]);
+    let mut txout_index = init_txout_index(external_descriptor.clone(), internal_descriptor.clone(), 0);
+    let external_spk_0 = external_descriptor.at_derivation_index(0).unwrap().script_pubkey();
+    let external_spk_16 = external_descriptor.at_derivation_index(16).unwrap().script_pubkey();
+    let external_spk_26 = external_descriptor.at_derivation_index(26).unwrap().script_pubkey();
+    let external_spk_27 = external_descriptor.at_derivation_index(27).unwrap().script_pubkey();
 
     // - nothing is derived
     // - unused list is also empty
@@ -293,13 +402,13 @@ fn test_wildcard_derivations() {
     // - next_derivation_index() == (0, true)
     // - derive_new() == ((0, <spk>), keychain::ChangeSet)
     // - next_unused() == ((0, <spk>), keychain::ChangeSet:is_empty())
-    assert_eq!(txout_index.next_index(&TestKeychain::External), (0, true));
-    let (spk, changeset) = txout_index.reveal_next_spk(&TestKeychain::External);
+    assert_eq!(txout_index.next_index(&TestKeychain::External).unwrap(), (0, true));
+    let (spk, changeset) = txout_index.reveal_next_spk(&TestKeychain::External).unwrap();
     assert_eq!(spk, (0_u32, external_spk_0.as_script()));
-    assert_eq!(changeset.as_inner(), &[(TestKeychain::External, 0)].into());
-    let (spk, changeset) = txout_index.next_unused_spk(&TestKeychain::External);
+    assert_eq!(&changeset.last_revealed, &[(external_descriptor.descriptor_id(), 0)].into());
+    let (spk, changeset) = txout_index.next_unused_spk(&TestKeychain::External).unwrap();
     assert_eq!(spk, (0_u32, external_spk_0.as_script()));
-    assert_eq!(changeset.as_inner(), &[].into());
+    assert_eq!(&changeset.last_revealed, &[].into());
 
     // - derived till 25
     // - used all spks till 15.
@@ -313,42 +422,43 @@ fn test_wildcard_derivations() {
 
     (0..=15)
         .chain([17, 20, 23])
-        .for_each(|index| assert!(txout_index.mark_used(&TestKeychain::External, index)));
+        .for_each(|index| assert!(txout_index.mark_used(TestKeychain::External, index)));
 
-    assert_eq!(txout_index.next_index(&TestKeychain::External), (26, true));
+    assert_eq!(txout_index.next_index(&TestKeychain::External).unwrap(), (26, true));
 
-    let (spk, changeset) = txout_index.reveal_next_spk(&TestKeychain::External);
+    let (spk, changeset) = txout_index.reveal_next_spk(&TestKeychain::External).unwrap();
     assert_eq!(spk, (26, external_spk_26.as_script()));
 
-    assert_eq!(changeset.as_inner(), &[(TestKeychain::External, 26)].into());
+    assert_eq!(&changeset.last_revealed, &[(external_descriptor.descriptor_id(), 26)].into());
 
-    let (spk, changeset) = txout_index.next_unused_spk(&TestKeychain::External);
+    let (spk, changeset) = txout_index.next_unused_spk(&TestKeychain::External).unwrap();
     assert_eq!(spk, (16, external_spk_16.as_script()));
-    assert_eq!(changeset.as_inner(), &[].into());
+    assert_eq!(&changeset.last_revealed, &[].into());
 
     // - Use all the derived till 26.
     // - next_unused() = ((27, <spk>), keychain::ChangeSet)
     (0..=26).for_each(|index| {
-        txout_index.mark_used(&TestKeychain::External, index);
+        txout_index.mark_used(TestKeychain::External, index);
     });
 
-    let (spk, changeset) = txout_index.next_unused_spk(&TestKeychain::External);
+    let (spk, changeset) = txout_index.next_unused_spk(&TestKeychain::External).unwrap();
     assert_eq!(spk, (27, external_spk_27.as_script()));
-    assert_eq!(changeset.as_inner(), &[(TestKeychain::External, 27)].into());
+    assert_eq!(&changeset.last_revealed, &[(external_descriptor.descriptor_id(), 27)].into());
 }
 
 #[test]
 fn test_non_wildcard_derivations() {
-    let mut txout_index = KeychainTxOutIndex::<TestKeychain>::default();
+    let mut txout_index = KeychainTxOutIndex::<TestKeychain>::new(0);
 
     let secp = bitcoin::secp256k1::Secp256k1::signing_only();
-    let (no_wildcard_descriptor, _) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, "wpkh([73c5da0a/86'/0'/0']xprv9xgqHN7yz9MwCkxsBPN5qetuNdQSUttZNKw1dcYTV4mkaAFiBVGQziHs3NRSWMkCzvgjEe3n9xV8oYywvM8at9yRqyaZVz6TYYhX98VjsUk/1/0)").unwrap();
+    let (no_wildcard_descriptor, _) =
+        Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, DESCRIPTORS[6]).unwrap();
     let external_spk = no_wildcard_descriptor
         .at_derivation_index(0)
         .unwrap()
         .script_pubkey();
 
-    txout_index.add_keychain(TestKeychain::External, no_wildcard_descriptor);
+    let _ = txout_index.insert_descriptor(TestKeychain::External, no_wildcard_descriptor.clone());
 
     // given:
     // - `txout_index` with no stored scripts
@@ -356,14 +466,24 @@ fn test_non_wildcard_derivations() {
     // - next derivation index should be new
     // - when we derive a new script, script @ index 0
     // - when we get the next unused script, script @ index 0
-    assert_eq!(txout_index.next_index(&TestKeychain::External), (0, true));
-    let (spk, changeset) = txout_index.reveal_next_spk(&TestKeychain::External);
+    assert_eq!(
+        txout_index.next_index(&TestKeychain::External).unwrap(),
+        (0, true)
+    );
+    let (spk, changeset) = txout_index
+        .reveal_next_spk(&TestKeychain::External)
+        .unwrap();
     assert_eq!(spk, (0, external_spk.as_script()));
-    assert_eq!(changeset.as_inner(), &[(TestKeychain::External, 0)].into());
+    assert_eq!(
+        &changeset.last_revealed,
+        &[(no_wildcard_descriptor.descriptor_id(), 0)].into()
+    );
 
-    let (spk, changeset) = txout_index.next_unused_spk(&TestKeychain::External);
+    let (spk, changeset) = txout_index
+        .next_unused_spk(&TestKeychain::External)
+        .unwrap();
     assert_eq!(spk, (0, external_spk.as_script()));
-    assert_eq!(changeset.as_inner(), &[].into());
+    assert_eq!(&changeset.last_revealed, &[].into());
 
     // given:
     // - the non-wildcard descriptor already has a stored and used script
@@ -371,26 +491,289 @@ fn test_non_wildcard_derivations() {
     // - next derivation index should not be new
     // - derive new and next unused should return the old script
     // - store_up_to should not panic and return empty changeset
-    assert_eq!(txout_index.next_index(&TestKeychain::External), (0, false));
-    txout_index.mark_used(&TestKeychain::External, 0);
+    assert_eq!(
+        txout_index.next_index(&TestKeychain::External).unwrap(),
+        (0, false)
+    );
+    txout_index.mark_used(TestKeychain::External, 0);
 
-    let (spk, changeset) = txout_index.reveal_next_spk(&TestKeychain::External);
+    let (spk, changeset) = txout_index
+        .reveal_next_spk(&TestKeychain::External)
+        .unwrap();
     assert_eq!(spk, (0, external_spk.as_script()));
-    assert_eq!(changeset.as_inner(), &[].into());
+    assert_eq!(&changeset.last_revealed, &[].into());
 
-    let (spk, changeset) = txout_index.next_unused_spk(&TestKeychain::External);
+    let (spk, changeset) = txout_index
+        .next_unused_spk(&TestKeychain::External)
+        .unwrap();
     assert_eq!(spk, (0, external_spk.as_script()));
-    assert_eq!(changeset.as_inner(), &[].into());
-    let (revealed_spks, revealed_changeset) =
-        txout_index.reveal_to_target(&TestKeychain::External, 200);
+    assert_eq!(&changeset.last_revealed, &[].into());
+    let (revealed_spks, revealed_changeset) = txout_index
+        .reveal_to_target(&TestKeychain::External, 200)
+        .unwrap();
     assert_eq!(revealed_spks.count(), 0);
     assert!(revealed_changeset.is_empty());
 
     // we check that spks_of_keychain returns a SpkIterator with just one element
     assert_eq!(
         txout_index
-            .spks_of_keychain(&TestKeychain::External)
+            .revealed_keychain_spks(&TestKeychain::External)
             .count(),
         1,
     );
 }
+
+/// Check that calling `lookahead_to_target` stores the expected spks.
+#[test]
+fn lookahead_to_target() {
+    #[derive(Default)]
+    struct TestCase {
+        /// Global lookahead value.
+        lookahead: u32,
+        /// Last revealed index for external keychain.
+        external_last_revealed: Option<u32>,
+        /// Last revealed index for internal keychain.
+        internal_last_revealed: Option<u32>,
+        /// Call `lookahead_to_target(External, u32)`.
+        external_target: Option<u32>,
+        /// Call `lookahead_to_target(Internal, u32)`.
+        internal_target: Option<u32>,
+    }
+
+    let test_cases = &[
+        TestCase {
+            lookahead: 0,
+            external_target: Some(100),
+            ..Default::default()
+        },
+        TestCase {
+            lookahead: 10,
+            internal_target: Some(99),
+            ..Default::default()
+        },
+        TestCase {
+            lookahead: 100,
+            internal_target: Some(9),
+            external_target: Some(10),
+            ..Default::default()
+        },
+        TestCase {
+            lookahead: 12,
+            external_last_revealed: Some(2),
+            internal_last_revealed: Some(2),
+            internal_target: Some(15),
+            external_target: Some(13),
+        },
+        TestCase {
+            lookahead: 13,
+            external_last_revealed: Some(100),
+            internal_last_revealed: Some(21),
+            internal_target: Some(120),
+            external_target: Some(130),
+        },
+    ];
+
+    for t in test_cases {
+        let external_descriptor = parse_descriptor(DESCRIPTORS[0]);
+        let internal_descriptor = parse_descriptor(DESCRIPTORS[1]);
+        let mut index = init_txout_index(
+            external_descriptor.clone(),
+            internal_descriptor.clone(),
+            t.lookahead,
+        );
+
+        if let Some(last_revealed) = t.external_last_revealed {
+            let _ = index.reveal_to_target(&TestKeychain::External, last_revealed);
+        }
+        if let Some(last_revealed) = t.internal_last_revealed {
+            let _ = index.reveal_to_target(&TestKeychain::Internal, last_revealed);
+        }
+
+        let keychain_test_cases = [
+            (
+                external_descriptor.descriptor_id(),
+                TestKeychain::External,
+                t.external_last_revealed,
+                t.external_target,
+            ),
+            (
+                internal_descriptor.descriptor_id(),
+                TestKeychain::Internal,
+                t.internal_last_revealed,
+                t.internal_target,
+            ),
+        ];
+        for (descriptor_id, keychain, last_revealed, target) in keychain_test_cases {
+            if let Some(target) = target {
+                let original_last_stored_index = match last_revealed {
+                    Some(last_revealed) => Some(last_revealed + t.lookahead),
+                    None => t.lookahead.checked_sub(1),
+                };
+                let exp_last_stored_index = match original_last_stored_index {
+                    Some(original_last_stored_index) => {
+                        Ord::max(target, original_last_stored_index)
+                    }
+                    None => target,
+                };
+                index.lookahead_to_target(&keychain, target);
+                let keys = index
+                    .inner()
+                    .all_spks()
+                    .range((descriptor_id, 0)..=(descriptor_id, u32::MAX))
+                    .map(|(k, _)| *k)
+                    .collect::<Vec<_>>();
+                let exp_keys = core::iter::repeat(descriptor_id)
+                    .zip(0_u32..=exp_last_stored_index)
+                    .collect::<Vec<_>>();
+                assert_eq!(keys, exp_keys);
+            }
+        }
+    }
+}
+
+/// `::index_txout` should still index txouts with spks derived from descriptors without keychains.
+/// This includes properly refilling the lookahead for said descriptors.
+#[test]
+fn index_txout_after_changing_descriptor_under_keychain() {
+    let secp = bdk_chain::bitcoin::secp256k1::Secp256k1::signing_only();
+    let (desc_a, _) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, DESCRIPTORS[0])
+        .expect("descriptor 0 must be valid");
+    let (desc_b, _) = Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, DESCRIPTORS[1])
+        .expect("descriptor 1 must be valid");
+    let desc_id_a = desc_a.descriptor_id();
+
+    let mut txout_index = bdk_chain::keychain::KeychainTxOutIndex::<()>::new(10);
+
+    // Introduce `desc_a` under keychain `()` and replace the descriptor.
+    let _ = txout_index.insert_descriptor((), desc_a.clone());
+    let _ = txout_index.insert_descriptor((), desc_b.clone());
+
+    // Loop through spks in intervals of `lookahead` to create outputs with. We should always be
+    // able to index these outputs if `lookahead` is respected.
+    let spk_indices = [9, 19, 29, 39];
+    for i in spk_indices {
+        let spk_at_index = desc_a
+            .at_derivation_index(i)
+            .expect("must derive")
+            .script_pubkey();
+        let index_changeset = txout_index.index_txout(
+            // Use spk derivation index as vout as we just want an unique outpoint.
+            OutPoint::new(h!("mock_tx"), i as _),
+            &TxOut {
+                value: Amount::from_sat(10_000),
+                script_pubkey: spk_at_index,
+            },
+        );
+        assert_eq!(
+            index_changeset,
+            bdk_chain::keychain::ChangeSet {
+                keychains_added: BTreeMap::default(),
+                last_revealed: [(desc_id_a, i)].into(),
+            },
+            "must always increase last active if impl respects lookahead"
+        );
+    }
+}
+
+#[test]
+fn insert_descriptor_no_change() {
+    let secp = Secp256k1::signing_only();
+    let (desc, _) =
+        Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, DESCRIPTORS[0]).unwrap();
+    let mut txout_index = KeychainTxOutIndex::<()>::default();
+    assert_eq!(
+        txout_index.insert_descriptor((), desc.clone()),
+        keychain::ChangeSet {
+            keychains_added: [((), desc.clone())].into(),
+            last_revealed: Default::default()
+        },
+    );
+    assert_eq!(
+        txout_index.insert_descriptor((), desc.clone()),
+        keychain::ChangeSet::default(),
+        "inserting the same descriptor for keychain should return an empty changeset",
+    );
+}
+
+#[test]
+fn applying_changesets_one_by_one_vs_aggregate_must_have_same_result() {
+    let desc = parse_descriptor(DESCRIPTORS[0]);
+    let changesets: &[ChangeSet<TestKeychain>] = &[
+        ChangeSet {
+            keychains_added: [(TestKeychain::Internal, desc.clone())].into(),
+            last_revealed: [].into(),
+        },
+        ChangeSet {
+            keychains_added: [(TestKeychain::External, desc.clone())].into(),
+            last_revealed: [(desc.descriptor_id(), 12)].into(),
+        },
+    ];
+
+    let mut indexer_a = KeychainTxOutIndex::<TestKeychain>::new(0);
+    for changeset in changesets {
+        indexer_a.apply_changeset(changeset.clone());
+    }
+
+    let mut indexer_b = KeychainTxOutIndex::<TestKeychain>::new(0);
+    let aggregate_changesets = changesets
+        .iter()
+        .cloned()
+        .reduce(|mut agg, cs| {
+            agg.append(cs);
+            agg
+        })
+        .expect("must aggregate changesets");
+    indexer_b.apply_changeset(aggregate_changesets);
+
+    assert_eq!(
+        indexer_a.keychains().collect::<Vec<_>>(),
+        indexer_b.keychains().collect::<Vec<_>>()
+    );
+    assert_eq!(
+        indexer_a.spk_at_index(TestKeychain::External, 0),
+        indexer_b.spk_at_index(TestKeychain::External, 0)
+    );
+    assert_eq!(
+        indexer_a.spk_at_index(TestKeychain::Internal, 0),
+        indexer_b.spk_at_index(TestKeychain::Internal, 0)
+    );
+    assert_eq!(
+        indexer_a.last_revealed_indices(),
+        indexer_b.last_revealed_indices()
+    );
+}
+
+// When the same descriptor is associated with various keychains,
+// index methods only return the highest keychain by Ord
+#[test]
+fn test_only_highest_ord_keychain_is_returned() {
+    let desc = parse_descriptor(DESCRIPTORS[0]);
+
+    let mut indexer = KeychainTxOutIndex::<TestKeychain>::new(0);
+    let _ = indexer.insert_descriptor(TestKeychain::Internal, desc.clone());
+    let _ = indexer.insert_descriptor(TestKeychain::External, desc);
+
+    // reveal_next_spk will work with either keychain
+    let spk0: ScriptBuf = indexer
+        .reveal_next_spk(&TestKeychain::External)
+        .unwrap()
+        .0
+         .1
+        .into();
+    let spk1: ScriptBuf = indexer
+        .reveal_next_spk(&TestKeychain::Internal)
+        .unwrap()
+        .0
+         .1
+        .into();
+
+    // index_of_spk will always return External
+    assert_eq!(
+        indexer.index_of_spk(&spk0),
+        Some((TestKeychain::External, 0))
+    );
+    assert_eq!(
+        indexer.index_of_spk(&spk1),
+        Some((TestKeychain::External, 1))
+    );
+}

crates/chain/tests/test_local_chain.rs

@@ -1,7 +1,16 @@
-use bdk_chain::local_chain::{
-    AlterCheckPointError, CannotConnectError, ChangeSet, LocalChain, Update,
+#![cfg(feature = "miniscript")]
+
+use std::ops::{Bound, RangeBounds};
+
+use bdk_chain::{
+    local_chain::{
+        AlterCheckPointError, ApplyHeaderError, CannotConnectError, ChangeSet, CheckPoint,
+        LocalChain, MissingGenesisError,
+    },
+    BlockId,
 };
-use bitcoin::BlockHash;
+use bitcoin::{block::Header, hashes::Hash, BlockHash};
+use proptest::prelude::*;
 
 #[macro_use]
 mod common;
@@ -10,7 +19,7 @@ mod common;
 struct TestLocalChain<'a> {
     name: &'static str,
     chain: LocalChain,
-    update: Update,
+    update: CheckPoint,
     exp: ExpectedResult<'a>,
 }
 
@@ -288,6 +297,27 @@ fn update_local_chain() {
                 ],
             },
         },
+        // Allow update that is shorter than original chain
+        //        | 0 | 1 | 2 | 3 | 4 | 5
+        // chain  | A       C   D   E   F
+        // update | A       C   D'
+        TestLocalChain {
+            name: "allow update that is shorter than original chain",
+            chain: local_chain![(0, h!("_")), (2, h!("C")), (3, h!("D")), (4, h!("E")), (5, h!("F"))],
+            update: chain_update![(0, h!("_")), (2, h!("C")), (3, h!("D'"))],
+            exp: ExpectedResult::Ok {
+                changeset: &[
+                    (3, Some(h!("D'"))),
+                    (4, None),
+                    (5, None),
+                ],
+                init_changeset: &[
+                    (0, Some(h!("_"))),
+                    (2, Some(h!("C"))),
+                    (3, Some(h!("D'"))),
+                ],
+            },
+        },
     ]
     .into_iter()
     .for_each(TestLocalChain::run);
@@ -350,3 +380,469 @@ fn local_chain_insert_block() {
         assert_eq!(chain, t.expected_final, "[{}] unexpected final chain", i,);
     }
 }
+
+#[test]
+fn local_chain_disconnect_from() {
+    struct TestCase {
+        name: &'static str,
+        original: LocalChain,
+        disconnect_from: (u32, BlockHash),
+        exp_result: Result<ChangeSet, MissingGenesisError>,
+        exp_final: LocalChain,
+    }
+
+    let test_cases = [
+        TestCase {
+            name: "try_replace_genesis_should_fail",
+            original: local_chain![(0, h!("_"))],
+            disconnect_from: (0, h!("_")),
+            exp_result: Err(MissingGenesisError),
+            exp_final: local_chain![(0, h!("_"))],
+        },
+        TestCase {
+            name: "try_replace_genesis_should_fail_2",
+            original: local_chain![(0, h!("_")), (2, h!("B")), (3, h!("C"))],
+            disconnect_from: (0, h!("_")),
+            exp_result: Err(MissingGenesisError),
+            exp_final: local_chain![(0, h!("_")), (2, h!("B")), (3, h!("C"))],
+        },
+        TestCase {
+            name: "from_does_not_exist",
+            original: local_chain![(0, h!("_")), (3, h!("C"))],
+            disconnect_from: (2, h!("B")),
+            exp_result: Ok(ChangeSet::default()),
+            exp_final: local_chain![(0, h!("_")), (3, h!("C"))],
+        },
+        TestCase {
+            name: "from_has_different_blockhash",
+            original: local_chain![(0, h!("_")), (2, h!("B"))],
+            disconnect_from: (2, h!("not_B")),
+            exp_result: Ok(ChangeSet::default()),
+            exp_final: local_chain![(0, h!("_")), (2, h!("B"))],
+        },
+        TestCase {
+            name: "disconnect_one",
+            original: local_chain![(0, h!("_")), (2, h!("B"))],
+            disconnect_from: (2, h!("B")),
+            exp_result: Ok(ChangeSet::from_iter([(2, None)])),
+            exp_final: local_chain![(0, h!("_"))],
+        },
+        TestCase {
+            name: "disconnect_three",
+            original: local_chain![(0, h!("_")), (2, h!("B")), (3, h!("C")), (4, h!("D"))],
+            disconnect_from: (2, h!("B")),
+            exp_result: Ok(ChangeSet::from_iter([(2, None), (3, None), (4, None)])),
+            exp_final: local_chain![(0, h!("_"))],
+        },
+    ];
+
+    for (i, t) in test_cases.into_iter().enumerate() {
+        println!("Case {}: {}", i, t.name);
+
+        let mut chain = t.original;
+        let result = chain.disconnect_from(t.disconnect_from.into());
+        assert_eq!(
+            result, t.exp_result,
+            "[{}:{}] unexpected changeset result",
+            i, t.name
+        );
+        assert_eq!(
+            chain, t.exp_final,
+            "[{}:{}] unexpected final chain",
+            i, t.name
+        );
+    }
+}
+
+#[test]
+fn checkpoint_from_block_ids() {
+    struct TestCase<'a> {
+        name: &'a str,
+        blocks: &'a [(u32, BlockHash)],
+        exp_result: Result<(), Option<(u32, BlockHash)>>,
+    }
+
+    let test_cases = [
+        TestCase {
+            name: "in_order",
+            blocks: &[(0, h!("A")), (1, h!("B")), (3, h!("D"))],
+            exp_result: Ok(()),
+        },
+        TestCase {
+            name: "with_duplicates",
+            blocks: &[(1, h!("B")), (2, h!("C")), (2, h!("C'"))],
+            exp_result: Err(Some((2, h!("C")))),
+        },
+        TestCase {
+            name: "not_in_order",
+            blocks: &[(1, h!("B")), (3, h!("D")), (2, h!("C"))],
+            exp_result: Err(Some((3, h!("D")))),
+        },
+        TestCase {
+            name: "empty",
+            blocks: &[],
+            exp_result: Err(None),
+        },
+        TestCase {
+            name: "single",
+            blocks: &[(21, h!("million"))],
+            exp_result: Ok(()),
+        },
+    ];
+
+    for (i, t) in test_cases.into_iter().enumerate() {
+        println!("running test case {}: '{}'", i, t.name);
+        let result = CheckPoint::from_block_ids(
+            t.blocks
+                .iter()
+                .map(|&(height, hash)| BlockId { height, hash }),
+        );
+        match t.exp_result {
+            Ok(_) => {
+                assert!(result.is_ok(), "[{}:{}] should be Ok", i, t.name);
+                let result_vec = {
+                    let mut v = result
+                        .unwrap()
+                        .into_iter()
+                        .map(|cp| (cp.height(), cp.hash()))
+                        .collect::<Vec<_>>();
+                    v.reverse();
+                    v
+                };
+                assert_eq!(
+                    &result_vec, t.blocks,
+                    "[{}:{}] not equal to original block ids",
+                    i, t.name
+                );
+            }
+            Err(exp_last) => {
+                assert!(result.is_err(), "[{}:{}] should be Err", i, t.name);
+                let err = result.unwrap_err();
+                assert_eq!(
+                    err.as_ref()
+                        .map(|last_cp| (last_cp.height(), last_cp.hash())),
+                    exp_last,
+                    "[{}:{}] error's last cp height should be {:?}, got {:?}",
+                    i,
+                    t.name,
+                    exp_last,
+                    err
+                );
+            }
+        }
+    }
+}
+
+#[test]
+fn checkpoint_query() {
+    struct TestCase {
+        chain: LocalChain,
+        /// The heights we want to call [`CheckPoint::query`] with, represented as an inclusive
+        /// range.
+        ///
+        /// If a [`CheckPoint`] exists at that height, we expect [`CheckPoint::query`] to return
+        /// it. If not, [`CheckPoint::query`] should return `None`.
+        query_range: (u32, u32),
+    }
+
+    let test_cases = [
+        TestCase {
+            chain: local_chain![(0, h!("_")), (1, h!("A"))],
+            query_range: (0, 2),
+        },
+        TestCase {
+            chain: local_chain![(0, h!("_")), (2, h!("B")), (3, h!("C"))],
+            query_range: (0, 3),
+        },
+    ];
+
+    for t in test_cases.into_iter() {
+        let tip = t.chain.tip();
+        for h in t.query_range.0..=t.query_range.1 {
+            let query_result = tip.get(h);
+
+            // perform an exhausitive search for the checkpoint at height `h`
+            let exp_hash = t
+                .chain
+                .iter_checkpoints()
+                .find(|cp| cp.height() == h)
+                .map(|cp| cp.hash());
+
+            match query_result {
+                Some(cp) => {
+                    assert_eq!(Some(cp.hash()), exp_hash);
+                    assert_eq!(cp.height(), h);
+                }
+                None => assert!(exp_hash.is_none()),
+            }
+        }
+    }
+}
+
+#[test]
+fn checkpoint_insert() {
+    struct TestCase<'a> {
+        /// The name of the test.
+        name: &'a str,
+        /// The original checkpoint chain to call [`CheckPoint::insert`] on.
+        chain: &'a [(u32, BlockHash)],
+        /// The `block_id` to insert.
+        to_insert: (u32, BlockHash),
+        /// The expected final checkpoint chain after calling [`CheckPoint::insert`].
+        exp_final_chain: &'a [(u32, BlockHash)],
+    }
+
+    let test_cases = [
+        TestCase {
+            name: "insert_above_tip",
+            chain: &[(1, h!("a")), (2, h!("b"))],
+            to_insert: (4, h!("d")),
+            exp_final_chain: &[(1, h!("a")), (2, h!("b")), (4, h!("d"))],
+        },
+        TestCase {
+            name: "insert_already_exists_expect_no_change",
+            chain: &[(1, h!("a")), (2, h!("b")), (3, h!("c"))],
+            to_insert: (2, h!("b")),
+            exp_final_chain: &[(1, h!("a")), (2, h!("b")), (3, h!("c"))],
+        },
+        TestCase {
+            name: "insert_in_middle",
+            chain: &[(2, h!("b")), (4, h!("d")), (5, h!("e"))],
+            to_insert: (3, h!("c")),
+            exp_final_chain: &[(2, h!("b")), (3, h!("c")), (4, h!("d")), (5, h!("e"))],
+        },
+        TestCase {
+            name: "replace_one",
+            chain: &[(3, h!("c")), (4, h!("d")), (5, h!("e"))],
+            to_insert: (5, h!("E")),
+            exp_final_chain: &[(3, h!("c")), (4, h!("d")), (5, h!("E"))],
+        },
+        TestCase {
+            name: "insert_conflict_should_evict",
+            chain: &[(3, h!("c")), (4, h!("d")), (5, h!("e")), (6, h!("f"))],
+            to_insert: (4, h!("D")),
+            exp_final_chain: &[(3, h!("c")), (4, h!("D"))],
+        },
+    ];
+
+    fn genesis_block() -> impl Iterator<Item = BlockId> {
+        core::iter::once((0, h!("_"))).map(BlockId::from)
+    }
+
+    for (i, t) in test_cases.into_iter().enumerate() {
+        println!("Running [{}] '{}'", i, t.name);
+
+        let chain = CheckPoint::from_block_ids(
+            genesis_block().chain(t.chain.iter().copied().map(BlockId::from)),
+        )
+        .expect("test formed incorrectly, must construct checkpoint chain");
+
+        let exp_final_chain = CheckPoint::from_block_ids(
+            genesis_block().chain(t.exp_final_chain.iter().copied().map(BlockId::from)),
+        )
+        .expect("test formed incorrectly, must construct checkpoint chain");
+
+        assert_eq!(
+            chain.insert(t.to_insert.into()),
+            exp_final_chain,
+            "unexpected final chain"
+        );
+    }
+}
+
+#[test]
+fn local_chain_apply_header_connected_to() {
+    fn header_from_prev_blockhash(prev_blockhash: BlockHash) -> Header {
+        Header {
+            version: bitcoin::block::Version::default(),
+            prev_blockhash,
+            merkle_root: bitcoin::hash_types::TxMerkleNode::all_zeros(),
+            time: 0,
+            bits: bitcoin::CompactTarget::default(),
+            nonce: 0,
+        }
+    }
+
+    struct TestCase {
+        name: &'static str,
+        chain: LocalChain,
+        header: Header,
+        height: u32,
+        connected_to: BlockId,
+        exp_result: Result<Vec<(u32, Option<BlockHash>)>, ApplyHeaderError>,
+    }
+
+    let test_cases = [
+        {
+            let header = header_from_prev_blockhash(h!("_"));
+            let hash = header.block_hash();
+            let height = 1;
+            let connected_to = BlockId { height, hash };
+            TestCase {
+                name: "connected_to_self_header_applied_to_self",
+                chain: local_chain![(0, h!("_")), (height, hash)],
+                header,
+                height,
+                connected_to,
+                exp_result: Ok(vec![]),
+            }
+        },
+        {
+            let prev_hash = h!("A");
+            let prev_height = 1;
+            let header = header_from_prev_blockhash(prev_hash);
+            let hash = header.block_hash();
+            let height = prev_height + 1;
+            let connected_to = BlockId {
+                height: prev_height,
+                hash: prev_hash,
+            };
+            TestCase {
+                name: "connected_to_prev_header_applied_to_self",
+                chain: local_chain![(0, h!("_")), (prev_height, prev_hash)],
+                header,
+                height,
+                connected_to,
+                exp_result: Ok(vec![(height, Some(hash))]),
+            }
+        },
+        {
+            let header = header_from_prev_blockhash(BlockHash::all_zeros());
+            let hash = header.block_hash();
+            let height = 0;
+            let connected_to = BlockId { height, hash };
+            TestCase {
+                name: "genesis_applied_to_self",
+                chain: local_chain![(0, hash)],
+                header,
+                height,
+                connected_to,
+                exp_result: Ok(vec![]),
+            }
+        },
+        {
+            let header = header_from_prev_blockhash(h!("Z"));
+            let height = 10;
+            let hash = header.block_hash();
+            let prev_height = height - 1;
+            let prev_hash = header.prev_blockhash;
+            TestCase {
+                name: "connect_at_connected_to",
+                chain: local_chain![(0, h!("_")), (2, h!("B")), (3, h!("C"))],
+                header,
+                height: 10,
+                connected_to: BlockId {
+                    height: 3,
+                    hash: h!("C"),
+                },
+                exp_result: Ok(vec![(prev_height, Some(prev_hash)), (height, Some(hash))]),
+            }
+        },
+        {
+            let prev_hash = h!("A");
+            let prev_height = 1;
+            let header = header_from_prev_blockhash(prev_hash);
+            let connected_to = BlockId {
+                height: prev_height,
+                hash: h!("not_prev_hash"),
+            };
+            TestCase {
+                name: "inconsistent_prev_hash",
+                chain: local_chain![(0, h!("_")), (prev_height, h!("not_prev_hash"))],
+                header,
+                height: prev_height + 1,
+                connected_to,
+                exp_result: Err(ApplyHeaderError::InconsistentBlocks),
+            }
+        },
+        {
+            let prev_hash = h!("A");
+            let prev_height = 1;
+            let header = header_from_prev_blockhash(prev_hash);
+            let height = prev_height + 1;
+            let connected_to = BlockId {
+                height,
+                hash: h!("not_current_hash"),
+            };
+            TestCase {
+                name: "inconsistent_current_block",
+                chain: local_chain![(0, h!("_")), (height, h!("not_current_hash"))],
+                header,
+                height,
+                connected_to,
+                exp_result: Err(ApplyHeaderError::InconsistentBlocks),
+            }
+        },
+        {
+            let header = header_from_prev_blockhash(h!("B"));
+            let height = 3;
+            let connected_to = BlockId {
+                height: 4,
+                hash: h!("D"),
+            };
+            TestCase {
+                name: "connected_to_is_greater",
+                chain: local_chain![(0, h!("_")), (2, h!("B"))],
+                header,
+                height,
+                connected_to,
+                exp_result: Err(ApplyHeaderError::InconsistentBlocks),
+            }
+        },
+    ];
+
+    for (i, t) in test_cases.into_iter().enumerate() {
+        println!("running test case {}: '{}'", i, t.name);
+        let mut chain = t.chain;
+        let result = chain.apply_header_connected_to(&t.header, t.height, t.connected_to);
+        let exp_result = t
+            .exp_result
+            .map(|cs| cs.iter().cloned().collect::<ChangeSet>());
+        assert_eq!(result, exp_result, "[{}:{}] unexpected result", i, t.name);
+    }
+}
+
+fn generate_height_range_bounds(
+    height_upper_bound: u32,
+) -> impl Strategy<Value = (Bound<u32>, Bound<u32>)> {
+    fn generate_height_bound(height_upper_bound: u32) -> impl Strategy<Value = Bound<u32>> {
+        prop_oneof![
+            (0..height_upper_bound).prop_map(Bound::Included),
+            (0..height_upper_bound).prop_map(Bound::Excluded),
+            Just(Bound::Unbounded),
+        ]
+    }
+    (
+        generate_height_bound(height_upper_bound),
+        generate_height_bound(height_upper_bound),
+    )
+}
+
+fn generate_checkpoints(max_height: u32, max_count: usize) -> impl Strategy<Value = CheckPoint> {
+    proptest::collection::btree_set(1..max_height, 0..max_count).prop_map(|mut heights| {
+        heights.insert(0); // must have genesis
+        CheckPoint::from_block_ids(heights.into_iter().map(|height| {
+            let hash = bitcoin::hashes::Hash::hash(height.to_le_bytes().as_slice());
+            BlockId { height, hash }
+        }))
+        .expect("blocks must be in order as it comes from btreeset")
+    })
+}
+
+proptest! {
+    #![proptest_config(ProptestConfig {
+        ..Default::default()
+    })]
+
+    /// Ensure that [`CheckPoint::range`] returns the expected checkpoint heights by comparing it
+    /// against a more primitive approach.
+    #[test]
+    fn checkpoint_range(
+        range in generate_height_range_bounds(21_000),
+        cp in generate_checkpoints(21_000, 2100)
+    ) {
+        let exp_heights = cp.iter().map(|cp| cp.height()).filter(|h| range.contains(h)).collect::<Vec<u32>>();
+        let heights = cp.range(range).map(|cp| cp.height()).collect::<Vec<u32>>();
+        prop_assert_eq!(heights, exp_heights);
+    }
+}

crates/chain/tests/test_spk_txout_index.rs

@@ -1,5 +1,7 @@
 use bdk_chain::{indexed_tx_graph::Indexer, SpkTxOutIndex};
-use bitcoin::{absolute, OutPoint, ScriptBuf, Transaction, TxIn, TxOut};
+use bitcoin::{
+    absolute, transaction, Amount, OutPoint, ScriptBuf, SignedAmount, Transaction, TxIn, TxOut,
+};
 
 #[test]
 fn spk_txout_sent_and_received() {
@@ -11,26 +13,37 @@ fn spk_txout_sent_and_received() {
     index.insert_spk(1, spk2.clone());
 
     let tx1 = Transaction {
-        version: 0x02,
+        version: transaction::Version::TWO,
         lock_time: absolute::LockTime::ZERO,
         input: vec![],
         output: vec![TxOut {
-            value: 42_000,
+            value: Amount::from_sat(42_000),
             script_pubkey: spk1.clone(),
         }],
     };
 
-    assert_eq!(index.sent_and_received(&tx1), (0, 42_000));
-    assert_eq!(index.net_value(&tx1), 42_000);
+    assert_eq!(
+        index.sent_and_received(&tx1, ..),
+        (Amount::from_sat(0), Amount::from_sat(42_000))
+    );
+    assert_eq!(
+        index.sent_and_received(&tx1, ..1),
+        (Amount::from_sat(0), Amount::from_sat(42_000))
+    );
+    assert_eq!(
+        index.sent_and_received(&tx1, 1..),
+        (Amount::from_sat(0), Amount::from_sat(0))
+    );
+    assert_eq!(index.net_value(&tx1, ..), SignedAmount::from_sat(42_000));
     index.index_tx(&tx1);
     assert_eq!(
-        index.sent_and_received(&tx1),
-        (0, 42_000),
+        index.sent_and_received(&tx1, ..),
+        (Amount::from_sat(0), Amount::from_sat(42_000)),
         "shouldn't change after scanning"
     );
 
     let tx2 = Transaction {
-        version: 0x1,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![TxIn {
             previous_output: OutPoint {
@@ -41,18 +54,29 @@ fn spk_txout_sent_and_received() {
         }],
         output: vec![
             TxOut {
-                value: 20_000,
+                value: Amount::from_sat(20_000),
                 script_pubkey: spk2,
             },
             TxOut {
                 script_pubkey: spk1,
-                value: 30_000,
+                value: Amount::from_sat(30_000),
             },
         ],
     };
 
-    assert_eq!(index.sent_and_received(&tx2), (42_000, 50_000));
-    assert_eq!(index.net_value(&tx2), 8_000);
+    assert_eq!(
+        index.sent_and_received(&tx2, ..),
+        (Amount::from_sat(42_000), Amount::from_sat(50_000))
+    );
+    assert_eq!(
+        index.sent_and_received(&tx2, ..1),
+        (Amount::from_sat(42_000), Amount::from_sat(30_000))
+    );
+    assert_eq!(
+        index.sent_and_received(&tx2, 1..),
+        (Amount::from_sat(0), Amount::from_sat(20_000))
+    );
+    assert_eq!(index.net_value(&tx2, ..), SignedAmount::from_sat(8_000));
 }
 
 #[test]
@@ -73,11 +97,11 @@ fn mark_used() {
     assert!(spk_index.is_used(&1));
 
     let tx1 = Transaction {
-        version: 0x02,
+        version: transaction::Version::TWO,
         lock_time: absolute::LockTime::ZERO,
         input: vec![],
         output: vec![TxOut {
-            value: 42_000,
+            value: Amount::from_sat(42_000),
             script_pubkey: spk1,
         }],
     };

crates/chain/tests/test_tx_graph.rs

@@ -1,3 +1,5 @@
+#![cfg(feature = "miniscript")]
+
 #[macro_use]
 mod common;
 use bdk_chain::tx_graph::CalculateFeeError;
@@ -8,9 +10,13 @@ use bdk_chain::{
     Anchor, Append, BlockId, ChainOracle, ChainPosition, ConfirmationHeightAnchor,
 };
 use bitcoin::{
-    absolute, hashes::Hash, BlockHash, OutPoint, ScriptBuf, Transaction, TxIn, TxOut, Txid,
+    absolute, hashes::Hash, transaction, Amount, BlockHash, OutPoint, ScriptBuf, Transaction, TxIn,
+    TxOut, Txid,
 };
+use common::*;
 use core::iter;
+use rand::RngCore;
+use std::sync::Arc;
 use std::vec;
 
 #[test]
@@ -20,14 +26,14 @@ fn insert_txouts() {
         (
             OutPoint::new(h!("tx1"), 1),
             TxOut {
-                value: 10_000,
+                value: Amount::from_sat(10_000),
                 script_pubkey: ScriptBuf::new(),
             },
         ),
         (
             OutPoint::new(h!("tx1"), 2),
             TxOut {
-                value: 20_000,
+                value: Amount::from_sat(20_000),
                 script_pubkey: ScriptBuf::new(),
             },
         ),
@@ -37,21 +43,21 @@ fn insert_txouts() {
     let update_ops = [(
         OutPoint::new(h!("tx2"), 0),
         TxOut {
-            value: 20_000,
+            value: Amount::from_sat(20_000),
             script_pubkey: ScriptBuf::new(),
         },
     )];
 
     // One full transaction to be included in the update
     let update_txs = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![TxIn {
             previous_output: OutPoint::null(),
             ..Default::default()
         }],
         output: vec![TxOut {
-            value: 30_000,
+            value: Amount::from_sat(30_000),
             script_pubkey: ScriptBuf::new(),
         }],
     };
@@ -117,7 +123,7 @@ fn insert_txouts() {
         assert_eq!(
             graph.insert_tx(update_txs.clone()),
             ChangeSet {
-                txs: [update_txs.clone()].into(),
+                txs: [Arc::new(update_txs.clone())].into(),
                 ..Default::default()
             }
         );
@@ -141,7 +147,7 @@ fn insert_txouts() {
     assert_eq!(
         changeset,
         ChangeSet {
-            txs: [update_txs.clone()].into(),
+            txs: [Arc::new(update_txs.clone())].into(),
             txouts: update_ops.clone().into(),
             anchors: [(conf_anchor, update_txs.txid()), (unconf_anchor, h!("tx2"))].into(),
             last_seen: [(h!("tx2"), 1000000)].into()
@@ -161,14 +167,14 @@ fn insert_txouts() {
             (
                 1u32,
                 &TxOut {
-                    value: 10_000,
+                    value: Amount::from_sat(10_000),
                     script_pubkey: ScriptBuf::new(),
                 }
             ),
             (
                 2u32,
                 &TxOut {
-                    value: 20_000,
+                    value: Amount::from_sat(20_000),
                     script_pubkey: ScriptBuf::new(),
                 }
             )
@@ -181,7 +187,7 @@ fn insert_txouts() {
         [(
             0u32,
             &TxOut {
-                value: 30_000,
+                value: Amount::from_sat(30_000),
                 script_pubkey: ScriptBuf::new()
             }
         )]
@@ -192,7 +198,7 @@ fn insert_txouts() {
     assert_eq!(
         graph.initial_changeset(),
         ChangeSet {
-            txs: [update_txs.clone()].into(),
+            txs: [Arc::new(update_txs.clone())].into(),
             txouts: update_ops.into_iter().chain(original_ops).collect(),
             anchors: [(conf_anchor, update_txs.txid()), (unconf_anchor, h!("tx2"))].into(),
             last_seen: [(h!("tx2"), 1000000)].into()
@@ -203,7 +209,7 @@ fn insert_txouts() {
 #[test]
 fn insert_tx_graph_doesnt_count_coinbase_as_spent() {
     let tx = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![TxIn {
             previous_output: OutPoint::null(),
@@ -213,7 +219,8 @@ fn insert_tx_graph_doesnt_count_coinbase_as_spent() {
     };
 
     let mut graph = TxGraph::<()>::default();
-    let _ = graph.insert_tx(tx);
+    let changeset = graph.insert_tx(tx);
+    assert!(!changeset.is_empty());
     assert!(graph.outspends(OutPoint::null()).is_empty());
     assert!(graph.tx_spends(Txid::all_zeros()).next().is_none());
 }
@@ -221,10 +228,10 @@ fn insert_tx_graph_doesnt_count_coinbase_as_spent() {
 #[test]
 fn insert_tx_graph_keeps_track_of_spend() {
     let tx1 = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
     };
 
     let op = OutPoint {
@@ -233,7 +240,7 @@ fn insert_tx_graph_keeps_track_of_spend() {
     };
 
     let tx2 = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![TxIn {
             previous_output: op,
@@ -262,52 +269,57 @@ fn insert_tx_graph_keeps_track_of_spend() {
 #[test]
 fn insert_tx_can_retrieve_full_tx_from_graph() {
     let tx = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![TxIn {
             previous_output: OutPoint::null(),
             ..Default::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
     };
 
     let mut graph = TxGraph::<()>::default();
     let _ = graph.insert_tx(tx.clone());
-    assert_eq!(graph.get_tx(tx.txid()), Some(&tx));
+    assert_eq!(
+        graph.get_tx(tx.txid()).map(|tx| tx.as_ref().clone()),
+        Some(tx)
+    );
 }
 
 #[test]
 fn insert_tx_displaces_txouts() {
     let mut tx_graph = TxGraph::<()>::default();
     let tx = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![],
         output: vec![TxOut {
-            value: 42_000,
-            script_pubkey: ScriptBuf::default(),
+            value: Amount::from_sat(42_000),
+            script_pubkey: ScriptBuf::new(),
         }],
     };
 
-    let _ = tx_graph.insert_txout(
+    let changeset = tx_graph.insert_txout(
         OutPoint {
             txid: tx.txid(),
             vout: 0,
         },
         TxOut {
-            value: 1_337_000,
+            value: Amount::from_sat(1_337_000),
             script_pubkey: ScriptBuf::default(),
         },
     );
 
+    assert!(!changeset.is_empty());
+
     let _ = tx_graph.insert_txout(
         OutPoint {
             txid: tx.txid(),
             vout: 0,
         },
         TxOut {
-            value: 1_000_000_000,
-            script_pubkey: ScriptBuf::default(),
+            value: Amount::from_sat(1_000_000_000),
+            script_pubkey: ScriptBuf::new(),
         },
     );
 
@@ -321,7 +333,7 @@ fn insert_tx_displaces_txouts() {
             })
             .unwrap()
             .value,
-        42_000
+        Amount::from_sat(42_000)
     );
     assert_eq!(
         tx_graph.get_txout(OutPoint {
@@ -336,12 +348,12 @@ fn insert_tx_displaces_txouts() {
 fn insert_txout_does_not_displace_tx() {
     let mut tx_graph = TxGraph::<()>::default();
     let tx = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![],
         output: vec![TxOut {
-            value: 42_000,
-            script_pubkey: ScriptBuf::default(),
+            value: Amount::from_sat(42_000),
+            script_pubkey: ScriptBuf::new(),
         }],
     };
 
@@ -353,8 +365,8 @@ fn insert_txout_does_not_displace_tx() {
             vout: 0,
         },
         TxOut {
-            value: 1_337_000,
-            script_pubkey: ScriptBuf::default(),
+            value: Amount::from_sat(1_337_000),
+            script_pubkey: ScriptBuf::new(),
         },
     );
 
@@ -364,8 +376,8 @@ fn insert_txout_does_not_displace_tx() {
             vout: 0,
         },
         TxOut {
-            value: 1_000_000_000,
-            script_pubkey: ScriptBuf::default(),
+            value: Amount::from_sat(1_000_000_000),
+            script_pubkey: ScriptBuf::new(),
         },
     );
 
@@ -377,7 +389,7 @@ fn insert_txout_does_not_displace_tx() {
             })
             .unwrap()
             .value,
-        42_000
+        Amount::from_sat(42_000)
     );
     assert_eq!(
         tx_graph.get_txout(OutPoint {
@@ -392,21 +404,21 @@ fn insert_txout_does_not_displace_tx() {
 fn test_calculate_fee() {
     let mut graph = TxGraph::<()>::default();
     let intx1 = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![],
         output: vec![TxOut {
-            value: 100,
-            ..Default::default()
+            value: Amount::from_sat(100),
+            script_pubkey: ScriptBuf::new(),
         }],
     };
     let intx2 = Transaction {
-        version: 0x02,
+        version: transaction::Version::TWO,
         lock_time: absolute::LockTime::ZERO,
         input: vec![],
         output: vec![TxOut {
-            value: 200,
-            ..Default::default()
+            value: Amount::from_sat(200),
+            script_pubkey: ScriptBuf::new(),
         }],
     };
 
@@ -416,8 +428,8 @@ fn test_calculate_fee() {
             vout: 0,
         },
         TxOut {
-            value: 300,
-            ..Default::default()
+            value: Amount::from_sat(300),
+            script_pubkey: ScriptBuf::new(),
         },
     );
 
@@ -426,7 +438,7 @@ fn test_calculate_fee() {
     let _ = graph.insert_txout(intxout1.0, intxout1.1);
 
     let mut tx = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![
             TxIn {
@@ -449,8 +461,8 @@ fn test_calculate_fee() {
             },
         ],
         output: vec![TxOut {
-            value: 500,
-            ..Default::default()
+            value: Amount::from_sat(500),
+            script_pubkey: ScriptBuf::new(),
         }],
     };
 
@@ -482,13 +494,13 @@ fn test_calculate_fee() {
 #[test]
 fn test_calculate_fee_on_coinbase() {
     let tx = Transaction {
-        version: 0x01,
+        version: transaction::Version::ONE,
         lock_time: absolute::LockTime::ZERO,
         input: vec![TxIn {
             previous_output: OutPoint::null(),
             ..Default::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
     };
 
     let graph = TxGraph::<()>::default();
@@ -524,7 +536,7 @@ fn test_walk_ancestors() {
             previous_output: OutPoint::new(h!("op0"), 0),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default(), TxOut::default()],
+        output: vec![TxOut::NULL, TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -534,7 +546,7 @@ fn test_walk_ancestors() {
             previous_output: OutPoint::new(tx_a0.txid(), 0),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default(), TxOut::default()],
+        output: vec![TxOut::NULL, TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -544,7 +556,7 @@ fn test_walk_ancestors() {
             previous_output: OutPoint::new(tx_a0.txid(), 1),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -553,7 +565,7 @@ fn test_walk_ancestors() {
             previous_output: OutPoint::new(h!("op1"), 0),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -563,7 +575,7 @@ fn test_walk_ancestors() {
             previous_output: OutPoint::new(tx_b0.txid(), 0),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -573,7 +585,7 @@ fn test_walk_ancestors() {
             previous_output: OutPoint::new(tx_b0.txid(), 1),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -589,7 +601,7 @@ fn test_walk_ancestors() {
                 ..TxIn::default()
             },
         ],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -598,7 +610,7 @@ fn test_walk_ancestors() {
             previous_output: OutPoint::new(h!("op2"), 0),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -608,7 +620,7 @@ fn test_walk_ancestors() {
             previous_output: OutPoint::new(tx_c1.txid(), 0),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -624,7 +636,7 @@ fn test_walk_ancestors() {
                 ..TxIn::default()
             },
         ],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -634,11 +646,11 @@ fn test_walk_ancestors() {
             previous_output: OutPoint::new(tx_d1.txid(), 0),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
-    let mut graph = TxGraph::<BlockId>::new(vec![
+    let mut graph = TxGraph::<BlockId>::new([
         tx_a0.clone(),
         tx_b0.clone(),
         tx_b1.clone(),
@@ -653,22 +665,23 @@ fn test_walk_ancestors() {
     ]);
 
     [&tx_a0, &tx_b1].iter().for_each(|&tx| {
-        let _ = graph.insert_anchor(tx.txid(), tip.block_id());
+        let changeset = graph.insert_anchor(tx.txid(), tip.block_id());
+        assert!(!changeset.is_empty());
     });
 
     let ancestors = [
         graph
-            .walk_ancestors(&tx_c0, |depth, tx| Some((depth, tx)))
+            .walk_ancestors(tx_c0.clone(), |depth, tx| Some((depth, tx)))
             .collect::<Vec<_>>(),
         graph
-            .walk_ancestors(&tx_d0, |depth, tx| Some((depth, tx)))
+            .walk_ancestors(tx_d0.clone(), |depth, tx| Some((depth, tx)))
             .collect::<Vec<_>>(),
         graph
-            .walk_ancestors(&tx_e0, |depth, tx| Some((depth, tx)))
+            .walk_ancestors(tx_e0.clone(), |depth, tx| Some((depth, tx)))
             .collect::<Vec<_>>(),
         // Only traverse unconfirmed ancestors of tx_e0 this time
         graph
-            .walk_ancestors(&tx_e0, |depth, tx| {
+            .walk_ancestors(tx_e0.clone(), |depth, tx| {
                 let tx_node = graph.get_tx_node(tx.txid())?;
                 for block in tx_node.anchors {
                     match local_chain.is_block_in_chain(block.anchor_block(), tip.block_id()) {
@@ -695,8 +708,14 @@ fn test_walk_ancestors() {
         vec![(1, &tx_d1), (2, &tx_c2), (2, &tx_c3), (3, &tx_b2)],
     ];
 
-    for (txids, expected_txids) in ancestors.iter().zip(expected_ancestors.iter()) {
-        assert_eq!(txids, expected_txids);
+    for (txids, expected_txids) in ancestors.into_iter().zip(expected_ancestors) {
+        assert_eq!(
+            txids,
+            expected_txids
+                .into_iter()
+                .map(|(i, tx)| (i, Arc::new(tx.clone())))
+                .collect::<Vec<_>>()
+        );
     }
 }
 
@@ -710,7 +729,7 @@ fn test_conflicting_descendants() {
             previous_output,
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -720,7 +739,7 @@ fn test_conflicting_descendants() {
             previous_output,
             ..TxIn::default()
         }],
-        output: vec![TxOut::default(), TxOut::default()],
+        output: vec![TxOut::NULL, TxOut::NULL],
         ..common::new_tx(1)
     };
 
@@ -730,7 +749,7 @@ fn test_conflicting_descendants() {
             previous_output: OutPoint::new(tx_a.txid(), 0),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(2)
     };
 
@@ -752,7 +771,7 @@ fn test_conflicting_descendants() {
 #[test]
 fn test_descendants_no_repeat() {
     let tx_a = Transaction {
-        output: vec![TxOut::default(), TxOut::default(), TxOut::default()],
+        output: vec![TxOut::NULL, TxOut::NULL, TxOut::NULL],
         ..common::new_tx(0)
     };
 
@@ -762,7 +781,7 @@ fn test_descendants_no_repeat() {
                 previous_output: OutPoint::new(tx_a.txid(), vout),
                 ..TxIn::default()
             }],
-            output: vec![TxOut::default()],
+            output: vec![TxOut::NULL],
             ..common::new_tx(1)
         })
         .collect::<Vec<_>>();
@@ -773,7 +792,7 @@ fn test_descendants_no_repeat() {
                 previous_output: OutPoint::new(txs_b[vout as usize].txid(), vout),
                 ..TxIn::default()
             }],
-            output: vec![TxOut::default()],
+            output: vec![TxOut::NULL],
             ..common::new_tx(2)
         })
         .collect::<Vec<_>>();
@@ -789,7 +808,7 @@ fn test_descendants_no_repeat() {
                 ..TxIn::default()
             },
         ],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(3)
     };
 
@@ -798,7 +817,7 @@ fn test_descendants_no_repeat() {
             previous_output: OutPoint::new(tx_d.txid(), 0),
             ..TxIn::default()
         }],
-        output: vec![TxOut::default()],
+        output: vec![TxOut::NULL],
         ..common::new_tx(4)
     };
 
@@ -808,7 +827,7 @@ fn test_descendants_no_repeat() {
                 previous_output: OutPoint::new(h!("tx_does_not_exist"), v),
                 ..TxIn::default()
             }],
-            output: vec![TxOut::default()],
+            output: vec![TxOut::NULL],
             ..common::new_tx(v)
         })
         .collect::<Vec<_>>();
@@ -855,11 +874,11 @@ fn test_chain_spends() {
         input: vec![],
         output: vec![
             TxOut {
-                value: 10_000,
+                value: Amount::from_sat(10_000),
                 script_pubkey: ScriptBuf::new(),
             },
             TxOut {
-                value: 20_000,
+                value: Amount::from_sat(20_000),
                 script_pubkey: ScriptBuf::new(),
             },
         ],
@@ -874,11 +893,11 @@ fn test_chain_spends() {
         }],
         output: vec![
             TxOut {
-                value: 5_000,
+                value: Amount::from_sat(5_000),
                 script_pubkey: ScriptBuf::new(),
             },
             TxOut {
-                value: 5_000,
+                value: Amount::from_sat(5_000),
                 script_pubkey: ScriptBuf::new(),
             },
         ],
@@ -893,11 +912,11 @@ fn test_chain_spends() {
         }],
         output: vec![
             TxOut {
-                value: 10_000,
+                value: Amount::from_sat(10_000),
                 script_pubkey: ScriptBuf::new(),
             },
             TxOut {
-                value: 10_000,
+                value: Amount::from_sat(10_000),
                 script_pubkey: ScriptBuf::new(),
             },
         ],
@@ -1027,10 +1046,12 @@ fn test_changeset_last_seen_append() {
             last_seen: original_ls.map(|ls| (txid, ls)).into_iter().collect(),
             ..Default::default()
         };
+        assert!(!original.is_empty() || original_ls.is_none());
         let update = ChangeSet::<()> {
             last_seen: update_ls.map(|ls| (txid, ls)).into_iter().collect(),
             ..Default::default()
         };
+        assert!(!update.is_empty() || update_ls.is_none());
 
         original.append(update);
         assert_eq!(
@@ -1041,134 +1062,112 @@ fn test_changeset_last_seen_append() {
 }
 
 #[test]
-fn test_missing_blocks() {
-    /// An anchor implementation for testing, made up of `(the_anchor_block, random_data)`.
-    #[derive(Debug, Clone, Eq, PartialEq, PartialOrd, Ord, core::hash::Hash)]
-    struct TestAnchor(BlockId);
+fn update_last_seen_unconfirmed() {
+    let mut graph = TxGraph::<()>::default();
+    let tx = new_tx(0);
+    let txid = tx.txid();
 
-    impl Anchor for TestAnchor {
-        fn anchor_block(&self) -> BlockId {
-            self.0
-        }
-    }
+    // insert a new tx
+    // initially we have a last_seen of 0, and no anchors
+    let _ = graph.insert_tx(tx);
+    let tx = graph.full_txs().next().unwrap();
+    assert_eq!(tx.last_seen_unconfirmed, 0);
+    assert!(tx.anchors.is_empty());
 
-    struct Scenario<'a> {
-        name: &'a str,
-        graph: TxGraph<TestAnchor>,
-        chain: LocalChain,
-        exp_heights: &'a [u32],
-    }
+    // higher timestamp should update last seen
+    let changeset = graph.update_last_seen_unconfirmed(2);
+    assert_eq!(changeset.last_seen.get(&txid).unwrap(), &2);
 
-    const fn new_anchor(height: u32, hash: BlockHash) -> TestAnchor {
-        TestAnchor(BlockId { height, hash })
-    }
+    // lower timestamp has no effect
+    let changeset = graph.update_last_seen_unconfirmed(1);
+    assert!(changeset.last_seen.is_empty());
 
-    fn new_scenario<'a>(
-        name: &'a str,
-        graph_anchors: &'a [(Txid, TestAnchor)],
-        chain: &'a [(u32, BlockHash)],
-        exp_heights: &'a [u32],
-    ) -> Scenario<'a> {
-        Scenario {
-            name,
-            graph: {
-                let mut g = TxGraph::default();
-                for (txid, anchor) in graph_anchors {
-                    let _ = g.insert_anchor(*txid, anchor.clone());
-                }
-                g
-            },
-            chain: {
-                let (mut c, _) = LocalChain::from_genesis_hash(h!("genesis"));
-                for (height, hash) in chain {
-                    let _ = c.insert_block(BlockId {
-                        height: *height,
-                        hash: *hash,
-                    });
-                }
-                c
-            },
-            exp_heights,
-        }
-    }
-
-    fn run(scenarios: &[Scenario]) {
-        for scenario in scenarios {
-            let Scenario {
-                name,
-                graph,
-                chain,
-                exp_heights,
-            } = scenario;
-
-            let heights = graph.missing_heights(chain).collect::<Vec<_>>();
-            assert_eq!(&heights, exp_heights, "scenario: {}", name);
-        }
-    }
-
-    run(&[
-        new_scenario(
-            "2 txs with the same anchor (2:B) which is missing from chain",
-            &[
-                (h!("tx_1"), new_anchor(2, h!("B"))),
-                (h!("tx_2"), new_anchor(2, h!("B"))),
-            ],
-            &[(1, h!("A")), (3, h!("C"))],
-            &[2],
-        ),
-        new_scenario(
-            "2 txs with different anchors at the same height, one of the anchors is missing",
-            &[
-                (h!("tx_1"), new_anchor(2, h!("B1"))),
-                (h!("tx_2"), new_anchor(2, h!("B2"))),
-            ],
-            &[(1, h!("A")), (2, h!("B1"))],
-            &[],
-        ),
-        new_scenario(
-            "tx with 2 anchors of same height which are missing from the chain",
-            &[
-                (h!("tx"), new_anchor(3, h!("C1"))),
-                (h!("tx"), new_anchor(3, h!("C2"))),
-            ],
-            &[(1, h!("A")), (4, h!("D"))],
-            &[3],
-        ),
-        new_scenario(
-            "tx with 2 anchors at the same height, chain has this height but does not match either anchor",
-            &[
-                (h!("tx"), new_anchor(4, h!("D1"))),
-                (h!("tx"), new_anchor(4, h!("D2"))),
-            ],
-            &[(4, h!("D3")), (5, h!("E"))],
-            &[],
-        ),
-        new_scenario(
-            "tx with 2 anchors at different heights, one anchor exists in chain, should return nothing",
-            &[
-                (h!("tx"), new_anchor(3, h!("C"))),
-                (h!("tx"), new_anchor(4, h!("D"))),
-            ],
-            &[(4, h!("D")), (5, h!("E"))],
-            &[],
-        ),
-        new_scenario(
-            "tx with 2 anchors at different heights, first height is already in chain with different hash, iterator should only return 2nd height",
-            &[
-                (h!("tx"), new_anchor(5, h!("E1"))),
-                (h!("tx"), new_anchor(6, h!("F1"))),
-            ],
-            &[(4, h!("D")), (5, h!("E")), (7, h!("G"))],
-            &[6],
-        ),
-        new_scenario(
-            "tx with 2 anchors at different heights, neither height is in chain, both heights should be returned",
-            &[
-                (h!("tx"), new_anchor(3, h!("C"))),
-                (h!("tx"), new_anchor(4, h!("D"))),
-            ],
-            &[(1, h!("A")), (2, h!("B"))],
-            &[3, 4],
-        ),
-    ]);
+    // once anchored, last seen is not updated
+    let _ = graph.insert_anchor(txid, ());
+    let changeset = graph.update_last_seen_unconfirmed(4);
+    assert!(changeset.is_empty());
+    assert_eq!(graph.full_txs().next().unwrap().last_seen_unconfirmed, 2);
+}
+
+#[test]
+/// The `map_anchors` allow a caller to pass a function to reconstruct the [`TxGraph`] with any [`Anchor`],
+/// even though the function is non-deterministic.
+fn call_map_anchors_with_non_deterministic_anchor() {
+    #[derive(Debug, Default, Clone, PartialEq, Eq, Copy, PartialOrd, Ord, core::hash::Hash)]
+    /// A non-deterministic anchor
+    pub struct NonDeterministicAnchor {
+        pub anchor_block: BlockId,
+        pub non_deterministic_field: u32,
+    }
+
+    let template = [
+        TxTemplate {
+            tx_name: "tx1",
+            inputs: &[TxInTemplate::Bogus],
+            outputs: &[TxOutTemplate::new(10000, Some(1))],
+            anchors: &[block_id!(1, "A")],
+            last_seen: None,
+        },
+        TxTemplate {
+            tx_name: "tx2",
+            inputs: &[TxInTemplate::PrevTx("tx1", 0)],
+            outputs: &[TxOutTemplate::new(20000, Some(2))],
+            anchors: &[block_id!(2, "B")],
+            ..Default::default()
+        },
+        TxTemplate {
+            tx_name: "tx3",
+            inputs: &[TxInTemplate::PrevTx("tx2", 0)],
+            outputs: &[TxOutTemplate::new(30000, Some(3))],
+            anchors: &[block_id!(3, "C"), block_id!(4, "D")],
+            ..Default::default()
+        },
+    ];
+    let (graph, _, _) = init_graph(&template);
+    let new_graph = graph.clone().map_anchors(|a| NonDeterministicAnchor {
+        anchor_block: a,
+        // A non-deterministic value
+        non_deterministic_field: rand::thread_rng().next_u32(),
+    });
+
+    // Check all the details in new_graph reconstruct as well
+
+    let mut full_txs_vec: Vec<_> = graph.full_txs().collect();
+    full_txs_vec.sort();
+    let mut new_txs_vec: Vec<_> = new_graph.full_txs().collect();
+    new_txs_vec.sort();
+    let mut new_txs = new_txs_vec.iter();
+
+    for tx_node in full_txs_vec.iter() {
+        let new_txnode = new_txs.next().unwrap();
+        assert_eq!(new_txnode.txid, tx_node.txid);
+        assert_eq!(new_txnode.tx, tx_node.tx);
+        assert_eq!(
+            new_txnode.last_seen_unconfirmed,
+            tx_node.last_seen_unconfirmed
+        );
+        assert_eq!(new_txnode.anchors.len(), tx_node.anchors.len());
+
+        let mut new_anchors: Vec<_> = new_txnode.anchors.iter().map(|a| a.anchor_block).collect();
+        new_anchors.sort();
+        let mut old_anchors: Vec<_> = tx_node.anchors.iter().copied().collect();
+        old_anchors.sort();
+        assert_eq!(new_anchors, old_anchors);
+    }
+    assert!(new_txs.next().is_none());
+
+    let new_graph_anchors: Vec<_> = new_graph
+        .all_anchors()
+        .iter()
+        .map(|i| i.0.anchor_block)
+        .collect();
+    assert_eq!(
+        new_graph_anchors,
+        vec![
+            block_id!(1, "A"),
+            block_id!(2, "B"),
+            block_id!(3, "C"),
+            block_id!(4, "D"),
+        ]
+    );
 }

crates/chain/tests/test_tx_graph_conflicts.rs

@@ -1,10 +1,12 @@
+#![cfg(feature = "miniscript")]
+
 #[macro_use]
 mod common;
 
 use std::collections::{BTreeSet, HashSet};
 
 use bdk_chain::{keychain::Balance, BlockId};
-use bitcoin::{OutPoint, Script};
+use bitcoin::{Amount, OutPoint, Script};
 use common::*;
 
 #[allow(dead_code)]
@@ -79,10 +81,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("confirmed_genesis", 0), ("confirmed_conflict", 0)]),
             exp_unspents: HashSet::from([("confirmed_conflict", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 0,
-                untrusted_pending: 0,
-                confirmed: 20000,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::ZERO,
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::from_sat(20000),
             },
         },
         Scenario {
@@ -110,14 +112,15 @@ fn test_tx_conflict_handling() {
                     ..Default::default()
                 },
             ],
+            // the txgraph is going to pick tx_conflict_2 because of higher lexicographical txid
             exp_chain_txs: HashSet::from(["tx1", "tx_conflict_2"]),
             exp_chain_txouts: HashSet::from([("tx1", 0), ("tx_conflict_2", 0)]),
             exp_unspents: HashSet::from([("tx_conflict_2", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 30000,
-                untrusted_pending: 0,
-                confirmed: 0,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::from_sat(30000),
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::ZERO,
             },
         },
         Scenario {
@@ -149,10 +152,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("tx1", 0), ("tx1", 1), ("tx_conflict_2", 0)]),
             exp_unspents: HashSet::from([("tx_conflict_2", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 30000,
-                untrusted_pending: 0,
-                confirmed: 0,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::from_sat(30000),
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::ZERO,
             },
         },
         Scenario {
@@ -191,10 +194,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("tx1", 0), ("tx_conflict_3", 0)]),
             exp_unspents: HashSet::from([("tx_conflict_3", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 40000,
-                untrusted_pending: 0,
-                confirmed: 0,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::from_sat(40000),
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::ZERO,
             },
         },
         Scenario {
@@ -226,10 +229,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("tx1", 0), ("tx_orphaned_conflict", 0)]),
             exp_unspents: HashSet::from([("tx_orphaned_conflict", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 30000,
-                untrusted_pending: 0,
-                confirmed: 0,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::from_sat(30000),
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::ZERO,
             },
         },
         Scenario {
@@ -261,10 +264,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("tx1", 0), ("tx_conflict_1", 0)]),
             exp_unspents: HashSet::from([("tx_conflict_1", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 20000,
-                untrusted_pending: 0,
-                confirmed: 0,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::from_sat(20000),
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::ZERO,
             },
         },
         Scenario {
@@ -310,10 +313,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("tx1", 0), ("tx_confirmed_conflict", 0)]),
             exp_unspents: HashSet::from([("tx_confirmed_conflict", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 0,
-                untrusted_pending: 0,
-                confirmed: 50000,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::ZERO,
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::from_sat(50000),
             },
         },
         Scenario {
@@ -355,10 +358,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("A", 0), ("B", 0), ("C", 0)]),
             exp_unspents: HashSet::from([("C", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 30000,
-                untrusted_pending: 0,
-                confirmed: 0,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::from_sat(30000),
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::ZERO,
             },
         },
         Scenario {
@@ -396,10 +399,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("A", 0), ("B'", 0)]),
             exp_unspents: HashSet::from([("B'", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 0,
-                untrusted_pending: 0,
-                confirmed: 20000,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::ZERO,
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::from_sat(20000),
             },
         },
         Scenario {
@@ -441,10 +444,10 @@ fn test_tx_conflict_handling() {
             ]),
             exp_unspents: HashSet::from([("C", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 30000,
-                untrusted_pending: 0,
-                confirmed: 0,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::from_sat(30000),
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::ZERO,
             },
         },
         Scenario {
@@ -486,10 +489,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("A", 0), ("B'", 0)]),
             exp_unspents: HashSet::from([("B'", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 30000,
-                untrusted_pending: 0,
-                confirmed: 0,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::from_sat(30000),
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::ZERO,
             },
         },
         Scenario {
@@ -531,10 +534,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("A", 0), ("B'", 0)]),
             exp_unspents: HashSet::from([("B'", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 0,
-                untrusted_pending: 0,
-                confirmed: 50000,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::ZERO,
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::from_sat(50000),
             },
         },
         Scenario {
@@ -582,10 +585,10 @@ fn test_tx_conflict_handling() {
             exp_chain_txouts: HashSet::from([("A", 0), ("B'", 0)]),
             exp_unspents: HashSet::from([("B'", 0)]),
             exp_balance: Balance {
-                immature: 0,
-                trusted_pending: 0,
-                untrusted_pending: 0,
-                confirmed: 50000,
+                immature: Amount::ZERO,
+                trusted_pending: Amount::ZERO,
+                untrusted_pending: Amount::ZERO,
+                confirmed: Amount::from_sat(50000),
             },
         },
     ];

crates/electrum/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bdk_electrum"
-version = "0.4.0"
+version = "0.13.0"
 edition = "2021"
 homepage = "https://bitcoindevkit.org"
 repository = "https://github.com/bitcoindevkit/bdk"
@@ -12,6 +12,9 @@ readme = "README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bdk_chain = { path = "../chain", version = "0.6.0", default-features = false }
-electrum-client = { version = "0.18" }
+bdk_chain = { path = "../chain", version = "0.14.0" }
+electrum-client = { version = "0.19" }
 #rustls = { version = "=0.21.1", optional = true, features = ["dangerous_configuration"] }
+
+[dev-dependencies]
+bdk_testenv = { path = "../testenv", default-features = false }

crates/electrum/README.md

@@ -1,3 +1,7 @@
 # BDK Electrum
 
-BDK Electrum client library for updating the keychain tracker.
+BDK Electrum extends [`electrum-client`] to update [`bdk_chain`] structures
+from an Electrum server.
+
+[`electrum-client`]: https://docs.rs/electrum-client/
+[`bdk_chain`]: https://docs.rs/bdk-chain/

crates/electrum/src/electrum_ext.rs

@@ -1,212 +1,82 @@
 use bdk_chain::{
     bitcoin::{OutPoint, ScriptBuf, Transaction, Txid},
-    local_chain::{self, CheckPoint},
-    tx_graph::{self, TxGraph},
-    Anchor, BlockId, ConfirmationHeightAnchor, ConfirmationTimeHeightAnchor,
-};
-use electrum_client::{Client, ElectrumApi, Error, HeaderNotification};
-use std::{
-    collections::{BTreeMap, BTreeSet, HashMap, HashSet},
-    fmt::Debug,
-    str::FromStr,
+    collections::{BTreeMap, HashMap, HashSet},
+    local_chain::CheckPoint,
+    spk_client::{FullScanRequest, FullScanResult, SyncRequest, SyncResult, TxCache},
+    tx_graph::TxGraph,
+    BlockId, ConfirmationHeightAnchor, ConfirmationTimeHeightAnchor,
 };
+use core::str::FromStr;
+use electrum_client::{ElectrumApi, Error, HeaderNotification};
+use std::sync::Arc;
 
 /// We include a chain suffix of a certain length for the purpose of robustness.
 const CHAIN_SUFFIX_LENGTH: u32 = 8;
 
-/// Represents updates fetched from an Electrum server, but excludes full transactions.
-///
-/// To provide a complete update to [`TxGraph`], you'll need to call [`Self::missing_full_txs`] to
-/// determine the full transactions missing from [`TxGraph`]. Then call [`Self::into_tx_graph`] to
-/// fetch the full transactions from Electrum and finalize the update.
-#[derive(Debug, Default, Clone)]
-pub struct RelevantTxids(HashMap<Txid, BTreeSet<ConfirmationHeightAnchor>>);
-
-impl RelevantTxids {
-    /// Determine the full transactions that are missing from `graph`.
-    ///
-    /// Refer to [`RelevantTxids`] for more details.
-    pub fn missing_full_txs<A: Anchor>(&self, graph: &TxGraph<A>) -> Vec<Txid> {
-        self.0
-            .keys()
-            .filter(move |&&txid| graph.as_ref().get_tx(txid).is_none())
-            .cloned()
-            .collect()
-    }
-
-    /// Finalizes the [`TxGraph`] update by fetching `missing` txids from the `client`.
-    ///
-    /// Refer to [`RelevantTxids`] for more details.
-    pub fn into_tx_graph(
-        self,
-        client: &Client,
-        seen_at: Option<u64>,
-        missing: Vec<Txid>,
-    ) -> Result<TxGraph<ConfirmationHeightAnchor>, Error> {
-        let new_txs = client.batch_transaction_get(&missing)?;
-        let mut graph = TxGraph::<ConfirmationHeightAnchor>::new(new_txs);
-        for (txid, anchors) in self.0 {
-            if let Some(seen_at) = seen_at {
-                let _ = graph.insert_seen_at(txid, seen_at);
-            }
-            for anchor in anchors {
-                let _ = graph.insert_anchor(txid, anchor);
-            }
-        }
-        Ok(graph)
-    }
-
-    /// Finalizes [`RelevantTxids`] with `new_txs` and anchors of type
-    /// [`ConfirmationTimeHeightAnchor`].
-    ///
-    /// **Note:** The confirmation time might not be precisely correct if there has been a reorg.
-    /// Electrum's API intends that we use the merkle proof API, we should change `bdk_electrum` to
-    /// use it.
-    pub fn into_confirmation_time_tx_graph(
-        self,
-        client: &Client,
-        seen_at: Option<u64>,
-        missing: Vec<Txid>,
-    ) -> Result<TxGraph<ConfirmationTimeHeightAnchor>, Error> {
-        let graph = self.into_tx_graph(client, seen_at, missing)?;
-
-        let relevant_heights = {
-            let mut visited_heights = HashSet::new();
-            graph
-                .all_anchors()
-                .iter()
-                .map(|(a, _)| a.confirmation_height_upper_bound())
-                .filter(move |&h| visited_heights.insert(h))
-                .collect::<Vec<_>>()
-        };
-
-        let height_to_time = relevant_heights
-            .clone()
-            .into_iter()
-            .zip(
-                client
-                    .batch_block_header(relevant_heights)?
-                    .into_iter()
-                    .map(|bh| bh.time as u64),
-            )
-            .collect::<HashMap<u32, u64>>();
-
-        let graph_changeset = {
-            let old_changeset = TxGraph::default().apply_update(graph);
-            tx_graph::ChangeSet {
-                txs: old_changeset.txs,
-                txouts: old_changeset.txouts,
-                last_seen: old_changeset.last_seen,
-                anchors: old_changeset
-                    .anchors
-                    .into_iter()
-                    .map(|(height_anchor, txid)| {
-                        let confirmation_height = height_anchor.confirmation_height;
-                        let confirmation_time = height_to_time[&confirmation_height];
-                        let time_anchor = ConfirmationTimeHeightAnchor {
-                            anchor_block: height_anchor.anchor_block,
-                            confirmation_height,
-                            confirmation_time,
-                        };
-                        (time_anchor, txid)
-                    })
-                    .collect(),
-            }
-        };
-
-        let mut new_graph = TxGraph::default();
-        new_graph.apply_changeset(graph_changeset);
-        Ok(new_graph)
-    }
-}
-
-/// Combination of chain and transactions updates from electrum
-///
-/// We have to update the chain and the txids at the same time since we anchor the txids to
-/// the same chain tip that we check before and after we gather the txids.
-#[derive(Debug)]
-pub struct ElectrumUpdate {
-    /// Chain update
-    pub chain_update: local_chain::Update,
-    /// Transaction updates from electrum
-    pub relevant_txids: RelevantTxids,
-}
-
-/// Trait to extend [`Client`] functionality.
+/// Trait to extend [`electrum_client::Client`] functionality.
 pub trait ElectrumExt {
-    /// Scan the blockchain (via electrum) for the data specified and returns updates for
-    /// [`bdk_chain`] data structures.
+    /// Full scan the keychain scripts specified with the blockchain (via an Electrum client) and
+    /// returns updates for [`bdk_chain`] data structures.
     ///
-    /// - `prev_tip`: the most recent blockchain tip present locally
-    /// - `keychain_spks`: keychains that we want to scan transactions for
-    /// - `txids`: transactions for which we want updated [`Anchor`]s
-    /// - `outpoints`: transactions associated with these outpoints (residing, spending) that we
-    ///     want to included in the update
-    ///
-    /// The scan for each keychain stops after a gap of `stop_gap` script pubkeys with no associated
-    /// transactions. `batch_size` specifies the max number of script pubkeys to request for in a
-    /// single batch request.
-    fn scan<K: Ord + Clone>(
+    /// - `request`: struct with data required to perform a spk-based blockchain client full scan,
+    ///              see [`FullScanRequest`]
+    /// - `stop_gap`: the full scan for each keychain stops after a gap of script pubkeys with no
+    ///              associated transactions
+    /// - `batch_size`: specifies the max number of script pubkeys to request for in a single batch
+    ///              request
+    /// - `fetch_prev_txouts`: specifies whether or not we want previous `TxOut`s for fee
+    ///              calculation
+    fn full_scan<K: Ord + Clone>(
         &self,
-        prev_tip: CheckPoint,
-        keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, ScriptBuf)>>,
-        txids: impl IntoIterator<Item = Txid>,
-        outpoints: impl IntoIterator<Item = OutPoint>,
+        request: FullScanRequest<K>,
         stop_gap: usize,
         batch_size: usize,
-    ) -> Result<(ElectrumUpdate, BTreeMap<K, u32>), Error>;
+        fetch_prev_txouts: bool,
+    ) -> Result<ElectrumFullScanResult<K>, Error>;
 
-    /// Convenience method to call [`scan`] without requiring a keychain.
+    /// Sync a set of scripts with the blockchain (via an Electrum client) for the data specified
+    /// and returns updates for [`bdk_chain`] data structures.
     ///
-    /// [`scan`]: ElectrumExt::scan
-    fn scan_without_keychain(
+    /// - `request`: struct with data required to perform a spk-based blockchain client sync,
+    ///              see [`SyncRequest`]
+    /// - `batch_size`: specifies the max number of script pubkeys to request for in a single batch
+    ///              request
+    /// - `fetch_prev_txouts`: specifies whether or not we want previous `TxOut`s for fee
+    ///              calculation
+    ///
+    /// If the scripts to sync are unknown, such as when restoring or importing a keychain that
+    /// may include scripts that have been used, use [`full_scan`] with the keychain.
+    ///
+    /// [`full_scan`]: ElectrumExt::full_scan
+    fn sync(
         &self,
-        prev_tip: CheckPoint,
-        misc_spks: impl IntoIterator<Item = ScriptBuf>,
-        txids: impl IntoIterator<Item = Txid>,
-        outpoints: impl IntoIterator<Item = OutPoint>,
+        request: SyncRequest,
         batch_size: usize,
-    ) -> Result<ElectrumUpdate, Error> {
-        let spk_iter = misc_spks
-            .into_iter()
-            .enumerate()
-            .map(|(i, spk)| (i as u32, spk));
-
-        let (electrum_update, _) = self.scan(
-            prev_tip,
-            [((), spk_iter)].into(),
-            txids,
-            outpoints,
-            usize::MAX,
-            batch_size,
-        )?;
-
-        Ok(electrum_update)
-    }
+        fetch_prev_txouts: bool,
+    ) -> Result<ElectrumSyncResult, Error>;
 }
 
-impl ElectrumExt for Client {
-    fn scan<K: Ord + Clone>(
+impl<E: ElectrumApi> ElectrumExt for E {
+    fn full_scan<K: Ord + Clone>(
         &self,
-        prev_tip: CheckPoint,
-        keychain_spks: BTreeMap<K, impl IntoIterator<Item = (u32, ScriptBuf)>>,
-        txids: impl IntoIterator<Item = Txid>,
-        outpoints: impl IntoIterator<Item = OutPoint>,
+        mut request: FullScanRequest<K>,
         stop_gap: usize,
         batch_size: usize,
-    ) -> Result<(ElectrumUpdate, BTreeMap<K, u32>), Error> {
-        let mut request_spks = keychain_spks
-            .into_iter()
-            .map(|(k, s)| (k, s.into_iter()))
-            .collect::<BTreeMap<K, _>>();
+        fetch_prev_txouts: bool,
+    ) -> Result<ElectrumFullScanResult<K>, Error> {
+        let mut request_spks = request.spks_by_keychain;
+
+        // We keep track of already-scanned spks just in case a reorg happens and we need to do a
+        // rescan. We need to keep track of this as iterators in `keychain_spks` are "unbounded" so
+        // cannot be collected. In addition, we keep track of whether an spk has an active tx
+        // history for determining the `last_active_index`.
+        // * key: (keychain, spk_index) that identifies the spk.
+        // * val: (script_pubkey, has_tx_history).
         let mut scanned_spks = BTreeMap::<(K, u32), (ScriptBuf, bool)>::new();
 
-        let txids = txids.into_iter().collect::<Vec<_>>();
-        let outpoints = outpoints.into_iter().collect::<Vec<_>>();
-
-        let (electrum_update, keychain_update) = loop {
-            let (tip, _) = construct_update_tip(self, prev_tip.clone())?;
-            let mut relevant_txids = RelevantTxids::default();
+        let update = loop {
+            let (tip, _) = construct_update_tip(self, request.chain_tip.clone())?;
+            let mut graph_update = TxGraph::<ConfirmationHeightAnchor>::default();
             let cps = tip
                 .iter()
                 .take(10)
@@ -218,7 +88,8 @@ impl ElectrumExt for Client {
                     scanned_spks.append(&mut populate_with_spks(
                         self,
                         &cps,
-                        &mut relevant_txids,
+                        &mut request.tx_cache,
+                        &mut graph_update,
                         &mut scanned_spks
                             .iter()
                             .map(|(i, (spk, _))| (i.clone(), spk.clone())),
@@ -231,7 +102,8 @@ impl ElectrumExt for Client {
                         populate_with_spks(
                             self,
                             &cps,
-                            &mut relevant_txids,
+                            &mut request.tx_cache,
+                            &mut graph_update,
                             keychain_spks,
                             stop_gap,
                             batch_size,
@@ -242,25 +114,18 @@ impl ElectrumExt for Client {
                 }
             }
 
-            populate_with_txids(self, &cps, &mut relevant_txids, &mut txids.iter().cloned())?;
-
-            let _txs = populate_with_outpoints(
-                self,
-                &cps,
-                &mut relevant_txids,
-                &mut outpoints.iter().cloned(),
-            )?;
-
             // check for reorgs during scan process
             let server_blockhash = self.block_header(tip.height() as usize)?.block_hash();
             if tip.hash() != server_blockhash {
                 continue; // reorg
             }
 
-            let chain_update = local_chain::Update {
-                tip,
-                introduce_older_blocks: true,
-            };
+            // Fetch previous `TxOut`s for fee calculation if flag is enabled.
+            if fetch_prev_txouts {
+                fetch_prev_txout(self, &mut request.tx_cache, &mut graph_update)?;
+            }
+
+            let chain_update = tip;
 
             let keychain_update = request_spks
                 .into_keys()
@@ -273,22 +138,151 @@ impl ElectrumExt for Client {
                 })
                 .collect::<BTreeMap<_, _>>();
 
-            break (
-                ElectrumUpdate {
-                    chain_update,
-                    relevant_txids,
-                },
-                keychain_update,
-            );
+            break FullScanResult {
+                graph_update,
+                chain_update,
+                last_active_indices: keychain_update,
+            };
         };
 
-        Ok((electrum_update, keychain_update))
+        Ok(ElectrumFullScanResult(update))
     }
+
+    fn sync(
+        &self,
+        request: SyncRequest,
+        batch_size: usize,
+        fetch_prev_txouts: bool,
+    ) -> Result<ElectrumSyncResult, Error> {
+        let mut tx_cache = request.tx_cache.clone();
+
+        let full_scan_req = FullScanRequest::from_chain_tip(request.chain_tip.clone())
+            .cache_txs(request.tx_cache)
+            .set_spks_for_keychain((), request.spks.enumerate().map(|(i, spk)| (i as u32, spk)));
+        let mut full_scan_res = self
+            .full_scan(full_scan_req, usize::MAX, batch_size, false)?
+            .with_confirmation_height_anchor();
+
+        let (tip, _) = construct_update_tip(self, request.chain_tip)?;
+        let cps = tip
+            .iter()
+            .take(10)
+            .map(|cp| (cp.height(), cp))
+            .collect::<BTreeMap<u32, CheckPoint>>();
+
+        populate_with_txids(
+            self,
+            &cps,
+            &mut tx_cache,
+            &mut full_scan_res.graph_update,
+            request.txids,
+        )?;
+        populate_with_outpoints(
+            self,
+            &cps,
+            &mut tx_cache,
+            &mut full_scan_res.graph_update,
+            request.outpoints,
+        )?;
+
+        // Fetch previous `TxOut`s for fee calculation if flag is enabled.
+        if fetch_prev_txouts {
+            fetch_prev_txout(self, &mut tx_cache, &mut full_scan_res.graph_update)?;
+        }
+
+        Ok(ElectrumSyncResult(SyncResult {
+            chain_update: full_scan_res.chain_update,
+            graph_update: full_scan_res.graph_update,
+        }))
+    }
+}
+
+/// The result of [`ElectrumExt::full_scan`].
+///
+/// This can be transformed into a [`FullScanResult`] with either [`ConfirmationHeightAnchor`] or
+/// [`ConfirmationTimeHeightAnchor`] anchor types.
+pub struct ElectrumFullScanResult<K>(FullScanResult<K, ConfirmationHeightAnchor>);
+
+impl<K> ElectrumFullScanResult<K> {
+    /// Return [`FullScanResult`] with [`ConfirmationHeightAnchor`].
+    pub fn with_confirmation_height_anchor(self) -> FullScanResult<K, ConfirmationHeightAnchor> {
+        self.0
+    }
+
+    /// Return [`FullScanResult`] with [`ConfirmationTimeHeightAnchor`].
+    ///
+    /// This requires additional calls to the Electrum server.
+    pub fn with_confirmation_time_height_anchor(
+        self,
+        client: &impl ElectrumApi,
+    ) -> Result<FullScanResult<K, ConfirmationTimeHeightAnchor>, Error> {
+        let res = self.0;
+        Ok(FullScanResult {
+            graph_update: try_into_confirmation_time_result(res.graph_update, client)?,
+            chain_update: res.chain_update,
+            last_active_indices: res.last_active_indices,
+        })
+    }
+}
+
+/// The result of [`ElectrumExt::sync`].
+///
+/// This can be transformed into a [`SyncResult`] with either [`ConfirmationHeightAnchor`] or
+/// [`ConfirmationTimeHeightAnchor`] anchor types.
+pub struct ElectrumSyncResult(SyncResult<ConfirmationHeightAnchor>);
+
+impl ElectrumSyncResult {
+    /// Return [`SyncResult`] with [`ConfirmationHeightAnchor`].
+    pub fn with_confirmation_height_anchor(self) -> SyncResult<ConfirmationHeightAnchor> {
+        self.0
+    }
+
+    /// Return [`SyncResult`] with [`ConfirmationTimeHeightAnchor`].
+    ///
+    /// This requires additional calls to the Electrum server.
+    pub fn with_confirmation_time_height_anchor(
+        self,
+        client: &impl ElectrumApi,
+    ) -> Result<SyncResult<ConfirmationTimeHeightAnchor>, Error> {
+        let res = self.0;
+        Ok(SyncResult {
+            graph_update: try_into_confirmation_time_result(res.graph_update, client)?,
+            chain_update: res.chain_update,
+        })
+    }
+}
+
+fn try_into_confirmation_time_result(
+    graph_update: TxGraph<ConfirmationHeightAnchor>,
+    client: &impl ElectrumApi,
+) -> Result<TxGraph<ConfirmationTimeHeightAnchor>, Error> {
+    let relevant_heights = graph_update
+        .all_anchors()
+        .iter()
+        .map(|(a, _)| a.confirmation_height)
+        .collect::<HashSet<_>>();
+
+    let height_to_time = relevant_heights
+        .clone()
+        .into_iter()
+        .zip(
+            client
+                .batch_block_header(relevant_heights)?
+                .into_iter()
+                .map(|bh| bh.time as u64),
+        )
+        .collect::<HashMap<u32, u64>>();
+
+    Ok(graph_update.map_anchors(|a| ConfirmationTimeHeightAnchor {
+        anchor_block: a.anchor_block,
+        confirmation_height: a.confirmation_height,
+        confirmation_time: height_to_time[&a.confirmation_height],
+    }))
 }
 
 /// Return a [`CheckPoint`] of the latest tip, that connects with `prev_tip`.
 fn construct_update_tip(
-    client: &Client,
+    client: &impl ElectrumApi,
     prev_tip: CheckPoint,
 ) -> Result<(CheckPoint, Option<u32>), Error> {
     let HeaderNotification { height, .. } = client.block_headers_subscribe()?;
@@ -401,48 +395,48 @@ fn determine_tx_anchor(
     }
 }
 
+/// Populate the `graph_update` with associated transactions/anchors of `outpoints`.
+///
+/// Transactions in which the outpoint resides, and transactions that spend from the outpoint are
+/// included. Anchors of the aforementioned transactions are included.
+///
+/// Checkpoints (in `cps`) are used to create anchors. The `tx_cache` is self-explanatory.
 fn populate_with_outpoints(
-    client: &Client,
+    client: &impl ElectrumApi,
     cps: &BTreeMap<u32, CheckPoint>,
-    relevant_txids: &mut RelevantTxids,
-    outpoints: &mut impl Iterator<Item = OutPoint>,
-) -> Result<HashMap<Txid, Transaction>, Error> {
-    let mut full_txs = HashMap::new();
+    tx_cache: &mut TxCache,
+    graph_update: &mut TxGraph<ConfirmationHeightAnchor>,
+    outpoints: impl IntoIterator<Item = OutPoint>,
+) -> Result<(), Error> {
     for outpoint in outpoints {
-        let txid = outpoint.txid;
-        let tx = client.transaction_get(&txid)?;
-        debug_assert_eq!(tx.txid(), txid);
-        let txout = match tx.output.get(outpoint.vout as usize) {
+        let op_txid = outpoint.txid;
+        let op_tx = fetch_tx(client, tx_cache, op_txid)?;
+        let op_txout = match op_tx.output.get(outpoint.vout as usize) {
             Some(txout) => txout,
             None => continue,
         };
+        debug_assert_eq!(op_tx.txid(), op_txid);
+
         // attempt to find the following transactions (alongside their chain positions), and
         // add to our sparsechain `update`:
         let mut has_residing = false; // tx in which the outpoint resides
         let mut has_spending = false; // tx that spends the outpoint
-        for res in client.script_get_history(&txout.script_pubkey)? {
+        for res in client.script_get_history(&op_txout.script_pubkey)? {
             if has_residing && has_spending {
                 break;
             }
 
-            if res.tx_hash == txid {
-                if has_residing {
-                    continue;
-                }
+            if !has_residing && res.tx_hash == op_txid {
                 has_residing = true;
-                full_txs.insert(res.tx_hash, tx.clone());
-            } else {
-                if has_spending {
-                    continue;
+                let _ = graph_update.insert_tx(Arc::clone(&op_tx));
+                if let Some(anchor) = determine_tx_anchor(cps, res.height, res.tx_hash) {
+                    let _ = graph_update.insert_anchor(res.tx_hash, anchor);
                 }
-                let res_tx = match full_txs.get(&res.tx_hash) {
-                    Some(tx) => tx,
-                    None => {
-                        let res_tx = client.transaction_get(&res.tx_hash)?;
-                        full_txs.insert(res.tx_hash, res_tx);
-                        full_txs.get(&res.tx_hash).expect("just inserted")
-                    }
-                };
+            }
+
+            if !has_spending && res.tx_hash != op_txid {
+                let res_tx = fetch_tx(client, tx_cache, res.tx_hash)?;
+                // we exclude txs/anchors that do not spend our specified outpoint(s)
                 has_spending = res_tx
                     .input
                     .iter()
@@ -450,26 +444,26 @@ fn populate_with_outpoints(
                 if !has_spending {
                     continue;
                 }
-            };
-
-            let anchor = determine_tx_anchor(cps, res.height, res.tx_hash);
-            let tx_entry = relevant_txids.0.entry(res.tx_hash).or_default();
-            if let Some(anchor) = anchor {
-                tx_entry.insert(anchor);
+                let _ = graph_update.insert_tx(Arc::clone(&res_tx));
+                if let Some(anchor) = determine_tx_anchor(cps, res.height, res.tx_hash) {
+                    let _ = graph_update.insert_anchor(res.tx_hash, anchor);
+                }
             }
         }
     }
-    Ok(full_txs)
+    Ok(())
 }
 
+/// Populate the `graph_update` with transactions/anchors of the provided `txids`.
 fn populate_with_txids(
-    client: &Client,
+    client: &impl ElectrumApi,
     cps: &BTreeMap<u32, CheckPoint>,
-    relevant_txids: &mut RelevantTxids,
-    txids: &mut impl Iterator<Item = Txid>,
+    tx_cache: &mut TxCache,
+    graph_update: &mut TxGraph<ConfirmationHeightAnchor>,
+    txids: impl IntoIterator<Item = Txid>,
 ) -> Result<(), Error> {
     for txid in txids {
-        let tx = match client.transaction_get(&txid) {
+        let tx = match fetch_tx(client, tx_cache, txid) {
             Ok(tx) => tx,
             Err(electrum_client::Error::Protocol(_)) => continue,
             Err(other_err) => return Err(other_err),
@@ -477,10 +471,12 @@ fn populate_with_txids(
 
         let spk = tx
             .output
-            .get(0)
+            .first()
             .map(|txo| &txo.script_pubkey)
             .expect("tx must have an output");
 
+        // because of restrictions of the Electrum API, we have to use the `script_get_history`
+        // call to get confirmation status of our transaction
         let anchor = match client
             .script_get_history(spk)?
             .into_iter()
@@ -490,18 +486,64 @@ fn populate_with_txids(
             None => continue,
         };
 
-        let tx_entry = relevant_txids.0.entry(txid).or_default();
+        let _ = graph_update.insert_tx(tx);
         if let Some(anchor) = anchor {
-            tx_entry.insert(anchor);
+            let _ = graph_update.insert_anchor(txid, anchor);
         }
     }
     Ok(())
 }
 
+/// Fetch transaction of given `txid`.
+///
+/// We maintain a `tx_cache` so that we won't need to fetch from Electrum with every call.
+fn fetch_tx<C: ElectrumApi>(
+    client: &C,
+    tx_cache: &mut TxCache,
+    txid: Txid,
+) -> Result<Arc<Transaction>, Error> {
+    use bdk_chain::collections::hash_map::Entry;
+    Ok(match tx_cache.entry(txid) {
+        Entry::Occupied(entry) => entry.get().clone(),
+        Entry::Vacant(entry) => entry
+            .insert(Arc::new(client.transaction_get(&txid)?))
+            .clone(),
+    })
+}
+
+// Helper function which fetches the `TxOut`s of our relevant transactions' previous transactions,
+// which we do not have by default. This data is needed to calculate the transaction fee.
+fn fetch_prev_txout<C: ElectrumApi>(
+    client: &C,
+    tx_cache: &mut TxCache,
+    graph_update: &mut TxGraph<ConfirmationHeightAnchor>,
+) -> Result<(), Error> {
+    let full_txs: Vec<Arc<Transaction>> =
+        graph_update.full_txs().map(|tx_node| tx_node.tx).collect();
+    for tx in full_txs {
+        for vin in &tx.input {
+            let outpoint = vin.previous_output;
+            let prev_tx = fetch_tx(client, tx_cache, outpoint.txid)?;
+            for txout in prev_tx.output.clone() {
+                let _ = graph_update.insert_txout(outpoint, txout);
+            }
+        }
+    }
+    Ok(())
+}
+
+/// Populate the `graph_update` with transactions/anchors associated with the given `spks`.
+///
+/// Transactions that contains an output with requested spk, or spends form an output with
+/// requested spk will be added to `graph_update`. Anchors of the aforementioned transactions are
+/// also included.
+///
+/// Checkpoints (in `cps`) are used to create anchors. The `tx_cache` is self-explanatory.
 fn populate_with_spks<I: Ord + Clone>(
-    client: &Client,
+    client: &impl ElectrumApi,
     cps: &BTreeMap<u32, CheckPoint>,
-    relevant_txids: &mut RelevantTxids,
+    tx_cache: &mut TxCache,
+    graph_update: &mut TxGraph<ConfirmationHeightAnchor>,
     spks: &mut impl Iterator<Item = (I, ScriptBuf)>,
     stop_gap: usize,
     batch_size: usize,
@@ -533,10 +575,10 @@ fn populate_with_spks<I: Ord + Clone>(
                 unused_spk_count = 0;
             }
 
-            for tx in spk_history {
-                let tx_entry = relevant_txids.0.entry(tx.tx_hash).or_default();
-                if let Some(anchor) = determine_tx_anchor(cps, tx.height, tx.tx_hash) {
-                    tx_entry.insert(anchor);
+            for tx_res in spk_history {
+                let _ = graph_update.insert_tx(fetch_tx(client, tx_cache, tx_res.tx_hash)?);
+                if let Some(anchor) = determine_tx_anchor(cps, tx_res.height, tx_res.tx_hash) {
+                    let _ = graph_update.insert_anchor(tx_res.tx_hash, anchor);
                 }
             }
         }

crates/electrum/src/lib.rs

@@ -1,26 +1,17 @@
-//! This crate is used for updating structures of the [`bdk_chain`] crate with data from electrum.
+//! This crate is used for updating structures of [`bdk_chain`] with data from an Electrum server.
 //!
-//! The star of the show is the [`ElectrumExt::scan`] method, which scans for relevant blockchain
-//! data (via electrum) and outputs updates for [`bdk_chain`] structures as a tuple of form:
+//! The two primary methods are [`ElectrumExt::sync`] and [`ElectrumExt::full_scan`]. In most cases
+//! [`ElectrumExt::sync`] is used to sync the transaction histories of scripts that the application
+//! cares about, for example the scripts for all the receive addresses of a Wallet's keychain that it
+//! has shown a user. [`ElectrumExt::full_scan`] is meant to be used when importing or restoring a
+//! keychain where the range of possibly used scripts is not known. In this case it is necessary to
+//! scan all keychain scripts until a number (the "stop gap") of unused scripts is discovered. For a
+//! sync or full scan the user receives relevant blockchain data and output updates for
+//! [`bdk_chain`].
 //!
-//! ([`bdk_chain::local_chain::Update`], [`RelevantTxids`], `keychain_update`)
+//! Refer to [`example_electrum`] for a complete example.
 //!
-//! An [`RelevantTxids`] only includes `txid`s and no full transactions. The caller is
-//! responsible for obtaining full transactions before applying. This can be done with
-//! these steps:
-//!
-//! 1. Determine which full transactions are missing. The method [`missing_full_txs`] of
-//! [`RelevantTxids`] can be used.
-//!
-//! 2. Obtaining the full transactions. To do this via electrum, the method
-//! [`batch_transaction_get`] can be used.
-//!
-//! Refer to [`bdk_electrum_example`] for a complete example.
-//!
-//! [`ElectrumClient::scan`]: electrum_client::ElectrumClient::scan
-//! [`missing_full_txs`]: RelevantTxids::missing_full_txs
-//! [`batch_transaction_get`]: electrum_client::ElectrumApi::batch_transaction_get
-//! [`bdk_electrum_example`]: https://github.com/LLFourn/bdk_core_staging/tree/master/bdk_electrum_example
+//! [`example_electrum`]: https://github.com/bitcoindevkit/bdk/tree/master/example-crates/example_electrum
 
 #![warn(missing_docs)]
 

crates/electrum/tests/test_electrum.rs

@@ -0,0 +1,217 @@
+use bdk_chain::{
+    bitcoin::{hashes::Hash, Address, Amount, ScriptBuf, WScriptHash},
+    keychain::Balance,
+    local_chain::LocalChain,
+    spk_client::SyncRequest,
+    ConfirmationTimeHeightAnchor, IndexedTxGraph, SpkTxOutIndex,
+};
+use bdk_electrum::ElectrumExt;
+use bdk_testenv::{anyhow, bitcoincore_rpc::RpcApi, TestEnv};
+
+fn get_balance(
+    recv_chain: &LocalChain,
+    recv_graph: &IndexedTxGraph<ConfirmationTimeHeightAnchor, SpkTxOutIndex<()>>,
+) -> anyhow::Result<Balance> {
+    let chain_tip = recv_chain.tip().block_id();
+    let outpoints = recv_graph.index.outpoints().clone();
+    let balance = recv_graph
+        .graph()
+        .balance(recv_chain, chain_tip, outpoints, |_, _| true);
+    Ok(balance)
+}
+
+/// Ensure that [`ElectrumExt`] can sync properly.
+///
+/// 1. Mine 101 blocks.
+/// 2. Send a tx.
+/// 3. Mine extra block to confirm sent tx.
+/// 4. Check [`Balance`] to ensure tx is confirmed.
+#[test]
+fn scan_detects_confirmed_tx() -> anyhow::Result<()> {
+    const SEND_AMOUNT: Amount = Amount::from_sat(10_000);
+
+    let env = TestEnv::new()?;
+    let client = electrum_client::Client::new(env.electrsd.electrum_url.as_str())?;
+
+    // Setup addresses.
+    let addr_to_mine = env
+        .bitcoind
+        .client
+        .get_new_address(None, None)?
+        .assume_checked();
+    let spk_to_track = ScriptBuf::new_p2wsh(&WScriptHash::all_zeros());
+    let addr_to_track = Address::from_script(&spk_to_track, bdk_chain::bitcoin::Network::Regtest)?;
+
+    // Setup receiver.
+    let (mut recv_chain, _) = LocalChain::from_genesis_hash(env.bitcoind.client.get_block_hash(0)?);
+    let mut recv_graph = IndexedTxGraph::<ConfirmationTimeHeightAnchor, _>::new({
+        let mut recv_index = SpkTxOutIndex::default();
+        recv_index.insert_spk((), spk_to_track.clone());
+        recv_index
+    });
+
+    // Mine some blocks.
+    env.mine_blocks(101, Some(addr_to_mine))?;
+
+    // Create transaction that is tracked by our receiver.
+    env.send(&addr_to_track, SEND_AMOUNT)?;
+
+    // Mine a block to confirm sent tx.
+    env.mine_blocks(1, None)?;
+
+    // Sync up to tip.
+    env.wait_until_electrum_sees_block()?;
+    let update = client
+        .sync(
+            SyncRequest::from_chain_tip(recv_chain.tip())
+                .chain_spks(core::iter::once(spk_to_track)),
+            5,
+            true,
+        )?
+        .with_confirmation_time_height_anchor(&client)?;
+
+    let _ = recv_chain
+        .apply_update(update.chain_update)
+        .map_err(|err| anyhow::anyhow!("LocalChain update error: {:?}", err))?;
+    let _ = recv_graph.apply_update(update.graph_update);
+
+    // Check to see if tx is confirmed.
+    assert_eq!(
+        get_balance(&recv_chain, &recv_graph)?,
+        Balance {
+            confirmed: SEND_AMOUNT,
+            ..Balance::default()
+        },
+    );
+
+    for tx in recv_graph.graph().full_txs() {
+        // Retrieve the calculated fee from `TxGraph`, which will panic if we do not have the
+        // floating txouts available from the transaction's previous outputs.
+        let fee = recv_graph
+            .graph()
+            .calculate_fee(&tx.tx)
+            .expect("fee must exist");
+
+        // Retrieve the fee in the transaction data from `bitcoind`.
+        let tx_fee = env
+            .bitcoind
+            .client
+            .get_transaction(&tx.txid, None)
+            .expect("Tx must exist")
+            .fee
+            .expect("Fee must exist")
+            .abs()
+            .to_sat() as u64;
+
+        // Check that the calculated fee matches the fee from the transaction data.
+        assert_eq!(fee, tx_fee);
+    }
+
+    Ok(())
+}
+
+/// Ensure that confirmed txs that are reorged become unconfirmed.
+///
+/// 1. Mine 101 blocks.
+/// 2. Mine 8 blocks with a confirmed tx in each.
+/// 3. Perform 8 separate reorgs on each block with a confirmed tx.
+/// 4. Check [`Balance`] after each reorg to ensure unconfirmed amount is correct.
+#[test]
+fn tx_can_become_unconfirmed_after_reorg() -> anyhow::Result<()> {
+    const REORG_COUNT: usize = 8;
+    const SEND_AMOUNT: Amount = Amount::from_sat(10_000);
+
+    let env = TestEnv::new()?;
+    let client = electrum_client::Client::new(env.electrsd.electrum_url.as_str())?;
+
+    // Setup addresses.
+    let addr_to_mine = env
+        .bitcoind
+        .client
+        .get_new_address(None, None)?
+        .assume_checked();
+    let spk_to_track = ScriptBuf::new_p2wsh(&WScriptHash::all_zeros());
+    let addr_to_track = Address::from_script(&spk_to_track, bdk_chain::bitcoin::Network::Regtest)?;
+
+    // Setup receiver.
+    let (mut recv_chain, _) = LocalChain::from_genesis_hash(env.bitcoind.client.get_block_hash(0)?);
+    let mut recv_graph = IndexedTxGraph::<ConfirmationTimeHeightAnchor, _>::new({
+        let mut recv_index = SpkTxOutIndex::default();
+        recv_index.insert_spk((), spk_to_track.clone());
+        recv_index
+    });
+
+    // Mine some blocks.
+    env.mine_blocks(101, Some(addr_to_mine))?;
+
+    // Create transactions that are tracked by our receiver.
+    for _ in 0..REORG_COUNT {
+        env.send(&addr_to_track, SEND_AMOUNT)?;
+        env.mine_blocks(1, None)?;
+    }
+
+    // Sync up to tip.
+    env.wait_until_electrum_sees_block()?;
+    let update = client
+        .sync(
+            SyncRequest::from_chain_tip(recv_chain.tip()).chain_spks([spk_to_track.clone()]),
+            5,
+            false,
+        )?
+        .with_confirmation_time_height_anchor(&client)?;
+
+    let _ = recv_chain
+        .apply_update(update.chain_update)
+        .map_err(|err| anyhow::anyhow!("LocalChain update error: {:?}", err))?;
+    let _ = recv_graph.apply_update(update.graph_update.clone());
+
+    // Retain a snapshot of all anchors before reorg process.
+    let initial_anchors = update.graph_update.all_anchors();
+
+    // Check if initial balance is correct.
+    assert_eq!(
+        get_balance(&recv_chain, &recv_graph)?,
+        Balance {
+            confirmed: SEND_AMOUNT * REORG_COUNT as u64,
+            ..Balance::default()
+        },
+        "initial balance must be correct",
+    );
+
+    // Perform reorgs with different depths.
+    for depth in 1..=REORG_COUNT {
+        env.reorg_empty_blocks(depth)?;
+
+        env.wait_until_electrum_sees_block()?;
+        let update = client
+            .sync(
+                SyncRequest::from_chain_tip(recv_chain.tip()).chain_spks([spk_to_track.clone()]),
+                5,
+                false,
+            )?
+            .with_confirmation_time_height_anchor(&client)?;
+
+        let _ = recv_chain
+            .apply_update(update.chain_update)
+            .map_err(|err| anyhow::anyhow!("LocalChain update error: {:?}", err))?;
+
+        // Check to see if a new anchor is added during current reorg.
+        if !initial_anchors.is_superset(update.graph_update.all_anchors()) {
+            println!("New anchor added at reorg depth {}", depth);
+        }
+        let _ = recv_graph.apply_update(update.graph_update);
+
+        assert_eq!(
+            get_balance(&recv_chain, &recv_graph)?,
+            Balance {
+                confirmed: SEND_AMOUNT * (REORG_COUNT - depth) as u64,
+                trusted_pending: SEND_AMOUNT * depth as u64,
+                ..Balance::default()
+            },
+            "reorg_count: {}",
+            depth,
+        );
+    }
+
+    Ok(())
+}

crates/esplora/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bdk_esplora"
-version = "0.4.0"
+version = "0.13.0"
 edition = "2021"
 homepage = "https://bitcoindevkit.org"
 repository = "https://github.com/bitcoindevkit/bdk"
@@ -12,23 +12,24 @@ readme = "README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bdk_chain = { path = "../chain", version = "0.6.0", default-features = false }
-esplora-client = { version = "0.6.0", default-features = false }
+bdk_chain = { path = "../chain", version = "0.14.0", default-features = false }
+esplora-client = { version = "0.7.0", default-features = false }
 async-trait = { version = "0.1.66", optional = true }
 futures = { version = "0.3.26", optional = true }
 
 # use these dependencies if you need to enable their /no-std features
-bitcoin = { version = "0.30.0", optional = true, default-features = false }
-miniscript = { version = "10.0.0", optional = true, default-features = false }
+bitcoin = { version = "0.31.0", optional = true, default-features = false }
+miniscript = { version = "11.0.0", optional = true, default-features = false }
 
-[target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]
-electrsd = { version= "0.25.0", features = ["bitcoind_25_0", "esplora_a33e97e1", "legacy"] }
+[dev-dependencies]
+bdk_testenv = { path = "../testenv", default_features = false }
 tokio = { version = "1", features = ["rt", "rt-multi-thread", "macros"] }
 
 [features]
-default = ["std", "async-https", "blocking"]
+default = ["std", "async-https", "blocking-https-rustls"]
 std = ["bdk_chain/std"]
 async = ["async-trait", "futures", "esplora-client/async"]
 async-https = ["async", "esplora-client/async-https"]
 async-https-rustls = ["async", "esplora-client/async-https-rustls"]
 blocking = ["esplora-client/blocking"]
+blocking-https-rustls = ["esplora-client/blocking-https-rustls"]

crates/esplora/README.md

@@ -30,7 +30,7 @@ use bdk_esplora::EsploraExt;
 // use bdk_esplora::EsploraAsyncExt;
 ```
 
-For full examples, refer to [`example-crates/wallet_esplora`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_esplora) (blocking) and [`example-crates/wallet_esplora_async`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_esplora_async).
+For full examples, refer to [`example-crates/wallet_esplora_blocking`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_esplora_blocking) and [`example-crates/wallet_esplora_async`](https://github.com/bitcoindevkit/bdk/tree/master/example-crates/wallet_esplora_async).
 
 [`esplora-client`]: https://docs.rs/esplora-client/
 [`bdk_chain`]: https://docs.rs/bdk-chain/

crates/esplora/src/async_ext.rs

@@ -1,15 +1,21 @@
+use std::collections::BTreeSet;
+
 use async_trait::async_trait;
-use bdk_chain::collections::btree_map;
+use bdk_chain::spk_client::{FullScanRequest, FullScanResult, SyncRequest, SyncResult};
+use bdk_chain::Anchor;
 use bdk_chain::{
-    bitcoin::{BlockHash, OutPoint, ScriptBuf, Txid},
-    collections::{BTreeMap, BTreeSet},
-    local_chain::{self, CheckPoint},
+    bitcoin::{BlockHash, OutPoint, ScriptBuf, TxOut, Txid},
+    collections::BTreeMap,
+    local_chain::CheckPoint,
     BlockId, ConfirmationTimeHeightAnchor, TxGraph,
 };
-use esplora_client::{Error, TxStatus};
+use esplora_client::{Amount, TxStatus};
 use futures::{stream::FuturesOrdered, TryStreamExt};
 
-use crate::{anchor_from_status, ASSUME_FINAL_DEPTH};
+use crate::anchor_from_status;
+
+/// [`esplora_client::Error`]
+type Error = Box<esplora_client::Error>;
 
 /// Trait to extend the functionality of [`esplora_client::AsyncClient`].
 ///
@@ -19,271 +25,251 @@ use crate::{anchor_from_status, ASSUME_FINAL_DEPTH};
 #[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
 #[cfg_attr(not(target_arch = "wasm32"), async_trait)]
 pub trait EsploraAsyncExt {
-    /// Prepare an [`LocalChain`] update with blocks fetched from Esplora.
+    /// Scan keychain scripts for transactions against Esplora, returning an update that can be
+    /// applied to the receiving structures.
     ///
-    /// * `local_tip` is the previous tip of [`LocalChain::tip`].
-    /// * `request_heights` is the block heights that we are interested in fetching from Esplora.
+    /// - `request`: struct with data required to perform a spk-based blockchain client full scan,
+    ///              see [`FullScanRequest`]
     ///
-    /// The result of this method can be applied to [`LocalChain::apply_update`].
+    /// The full scan for each keychain stops after a gap of `stop_gap` script pubkeys with no
+    /// associated transactions. `parallel_requests` specifies the max number of HTTP requests to
+    /// make in parallel.
     ///
-    /// [`LocalChain`]: bdk_chain::local_chain::LocalChain
-    /// [`LocalChain::tip`]: bdk_chain::local_chain::LocalChain::tip
-    /// [`LocalChain::apply_update`]: bdk_chain::local_chain::LocalChain::apply_update
-    #[allow(clippy::result_large_err)]
-    async fn update_local_chain(
+    /// ## Note
+    ///
+    /// `stop_gap` is defined as "the maximum number of consecutive unused addresses".
+    /// For example, with a `stop_gap` of  3, `full_scan` will keep scanning
+    /// until it encounters 3 consecutive script pubkeys with no associated transactions.
+    ///
+    /// This follows the same approach as other Bitcoin-related software,
+    /// such as [Electrum](https://electrum.readthedocs.io/en/latest/faq.html#what-is-the-gap-limit),
+    /// [BTCPay Server](https://docs.btcpayserver.org/FAQ/Wallet/#the-gap-limit-problem),
+    /// and [Sparrow](https://www.sparrowwallet.com/docs/faq.html#ive-restored-my-wallet-but-some-of-my-funds-are-missing).
+    ///
+    /// A `stop_gap` of 0 will be treated as a `stop_gap` of 1.
+    async fn full_scan<K: Ord + Clone + Send>(
         &self,
-        local_tip: CheckPoint,
-        request_heights: impl IntoIterator<IntoIter = impl Iterator<Item = u32> + Send> + Send,
-    ) -> Result<local_chain::Update, Error>;
-
-    /// Scan Esplora for the data specified and return a [`TxGraph`] and a map of last active
-    /// indices.
-    ///
-    /// * `keychain_spks`: keychains that we want to scan transactions for
-    /// * `txids`: transactions for which we want updated [`ConfirmationTimeHeightAnchor`]s
-    /// * `outpoints`: transactions associated with these outpoints (residing, spending) that we
-    ///     want to include in the update
-    ///
-    /// The scan for each keychain stops after a gap of `stop_gap` script pubkeys with no associated
-    /// transactions. `parallel_requests` specifies the max number of HTTP requests to make in
-    /// parallel.
-    #[allow(clippy::result_large_err)]
-    async fn scan_txs_with_keychains<K: Ord + Clone + Send>(
-        &self,
-        keychain_spks: BTreeMap<
-            K,
-            impl IntoIterator<IntoIter = impl Iterator<Item = (u32, ScriptBuf)> + Send> + Send,
-        >,
-        txids: impl IntoIterator<IntoIter = impl Iterator<Item = Txid> + Send> + Send,
-        outpoints: impl IntoIterator<IntoIter = impl Iterator<Item = OutPoint> + Send> + Send,
+        request: FullScanRequest<K>,
         stop_gap: usize,
         parallel_requests: usize,
-    ) -> Result<(TxGraph<ConfirmationTimeHeightAnchor>, BTreeMap<K, u32>), Error>;
+    ) -> Result<FullScanResult<K>, Error>;
 
-    /// Convenience method to call [`scan_txs_with_keychains`] without requiring a keychain.
+    /// Sync a set of scripts with the blockchain (via an Esplora client) for the data
+    /// specified and return a [`TxGraph`].
     ///
-    /// [`scan_txs_with_keychains`]: EsploraAsyncExt::scan_txs_with_keychains
-    #[allow(clippy::result_large_err)]
-    async fn scan_txs(
+    /// - `request`: struct with data required to perform a spk-based blockchain client sync, see
+    ///              [`SyncRequest`]
+    ///
+    /// If the scripts to sync are unknown, such as when restoring or importing a keychain that
+    /// may include scripts that have been used, use [`full_scan`] with the keychain.
+    ///
+    /// [`full_scan`]: EsploraAsyncExt::full_scan
+    async fn sync(
         &self,
-        misc_spks: impl IntoIterator<IntoIter = impl Iterator<Item = ScriptBuf> + Send> + Send,
-        txids: impl IntoIterator<IntoIter = impl Iterator<Item = Txid> + Send> + Send,
-        outpoints: impl IntoIterator<IntoIter = impl Iterator<Item = OutPoint> + Send> + Send,
+        request: SyncRequest,
         parallel_requests: usize,
-    ) -> Result<TxGraph<ConfirmationTimeHeightAnchor>, Error> {
-        self.scan_txs_with_keychains(
-            [(
-                (),
-                misc_spks
-                    .into_iter()
-                    .enumerate()
-                    .map(|(i, spk)| (i as u32, spk)),
-            )]
-            .into(),
-            txids,
-            outpoints,
-            usize::MAX,
-            parallel_requests,
-        )
-        .await
-        .map(|(g, _)| g)
-    }
+    ) -> Result<SyncResult, Error>;
 }
 
 #[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
 #[cfg_attr(not(target_arch = "wasm32"), async_trait)]
 impl EsploraAsyncExt for esplora_client::AsyncClient {
-    async fn update_local_chain(
+    async fn full_scan<K: Ord + Clone + Send>(
         &self,
-        local_tip: CheckPoint,
-        request_heights: impl IntoIterator<IntoIter = impl Iterator<Item = u32> + Send> + Send,
-    ) -> Result<local_chain::Update, Error> {
-        let request_heights = request_heights.into_iter().collect::<BTreeSet<_>>();
-        let new_tip_height = self.get_height().await?;
-
-        // atomically fetch blocks from esplora
-        let mut fetched_blocks = {
-            let heights = (0..=new_tip_height).rev();
-            let hashes = self
-                .get_blocks(Some(new_tip_height))
-                .await?
-                .into_iter()
-                .map(|b| b.id);
-            heights.zip(hashes).collect::<BTreeMap<u32, BlockHash>>()
-        };
-
-        // fetch heights that the caller is interested in
-        for height in request_heights {
-            // do not fetch blocks higher than remote tip
-            if height > new_tip_height {
-                continue;
-            }
-            // only fetch what is missing
-            if let btree_map::Entry::Vacant(entry) = fetched_blocks.entry(height) {
-                let hash = self.get_block_hash(height).await?;
-                entry.insert(hash);
-            }
-        }
-
-        // find the earliest point of agreement between local chain and fetched chain
-        let earliest_agreement_cp = {
-            let mut earliest_agreement_cp = Option::<CheckPoint>::None;
-
-            let local_tip_height = local_tip.height();
-            for local_cp in local_tip.iter() {
-                let local_block = local_cp.block_id();
-
-                // the updated hash (block hash at this height after the update), can either be:
-                // 1. a block that already existed in `fetched_blocks`
-                // 2. a block that exists locally and at least has a depth of ASSUME_FINAL_DEPTH
-                // 3. otherwise we can freshly fetch the block from remote, which is safe as it
-                //    is guaranteed that this would be at or below ASSUME_FINAL_DEPTH from the
-                //    remote tip
-                let updated_hash = match fetched_blocks.entry(local_block.height) {
-                    btree_map::Entry::Occupied(entry) => *entry.get(),
-                    btree_map::Entry::Vacant(entry) => *entry.insert(
-                        if local_tip_height - local_block.height >= ASSUME_FINAL_DEPTH {
-                            local_block.hash
-                        } else {
-                            self.get_block_hash(local_block.height).await?
-                        },
-                    ),
-                };
-
-                // since we may introduce blocks below the point of agreement, we cannot break
-                // here unconditionally - we only break if we guarantee there are no new heights
-                // below our current local checkpoint
-                if local_block.hash == updated_hash {
-                    earliest_agreement_cp = Some(local_cp);
-
-                    let first_new_height = *fetched_blocks
-                        .keys()
-                        .next()
-                        .expect("must have at least one new block");
-                    if first_new_height >= local_block.height {
-                        break;
-                    }
-                }
-            }
-
-            earliest_agreement_cp
-        };
-
-        let tip = {
-            // first checkpoint to use for the update chain
-            let first_cp = match earliest_agreement_cp {
-                Some(cp) => cp,
-                None => {
-                    let (&height, &hash) = fetched_blocks
-                        .iter()
-                        .next()
-                        .expect("must have at least one new block");
-                    CheckPoint::new(BlockId { height, hash })
-                }
-            };
-            // transform fetched chain into the update chain
-            fetched_blocks
-                // we exclude anything at or below the first cp of the update chain otherwise
-                // building the chain will fail
-                .split_off(&(first_cp.height() + 1))
-                .into_iter()
-                .map(|(height, hash)| BlockId { height, hash })
-                .fold(first_cp, |prev_cp, block| {
-                    prev_cp.push(block).expect("must extend checkpoint")
-                })
-        };
-
-        Ok(local_chain::Update {
-            tip,
-            introduce_older_blocks: true,
+        request: FullScanRequest<K>,
+        stop_gap: usize,
+        parallel_requests: usize,
+    ) -> Result<FullScanResult<K>, Error> {
+        let latest_blocks = fetch_latest_blocks(self).await?;
+        let (graph_update, last_active_indices) = full_scan_for_index_and_graph(
+            self,
+            request.spks_by_keychain,
+            stop_gap,
+            parallel_requests,
+        )
+        .await?;
+        let chain_update = chain_update(
+            self,
+            &latest_blocks,
+            &request.chain_tip,
+            graph_update.all_anchors(),
+        )
+        .await?;
+        Ok(FullScanResult {
+            chain_update,
+            graph_update,
+            last_active_indices,
         })
     }
 
-    async fn scan_txs_with_keychains<K: Ord + Clone + Send>(
+    async fn sync(
         &self,
-        keychain_spks: BTreeMap<
-            K,
-            impl IntoIterator<IntoIter = impl Iterator<Item = (u32, ScriptBuf)> + Send> + Send,
-        >,
-        txids: impl IntoIterator<IntoIter = impl Iterator<Item = Txid> + Send> + Send,
-        outpoints: impl IntoIterator<IntoIter = impl Iterator<Item = OutPoint> + Send> + Send,
-        stop_gap: usize,
+        request: SyncRequest,
         parallel_requests: usize,
-    ) -> Result<(TxGraph<ConfirmationTimeHeightAnchor>, BTreeMap<K, u32>), Error> {
-        type TxsOfSpkIndex = (u32, Vec<esplora_client::Tx>);
-        let parallel_requests = Ord::max(parallel_requests, 1);
-        let mut graph = TxGraph::<ConfirmationTimeHeightAnchor>::default();
-        let mut last_active_indexes = BTreeMap::<K, u32>::new();
+    ) -> Result<SyncResult, Error> {
+        let latest_blocks = fetch_latest_blocks(self).await?;
+        let graph_update = sync_for_index_and_graph(
+            self,
+            request.spks,
+            request.txids,
+            request.outpoints,
+            parallel_requests,
+        )
+        .await?;
+        let chain_update = chain_update(
+            self,
+            &latest_blocks,
+            &request.chain_tip,
+            graph_update.all_anchors(),
+        )
+        .await?;
+        Ok(SyncResult {
+            chain_update,
+            graph_update,
+        })
+    }
+}
 
-        for (keychain, spks) in keychain_spks {
-            let mut spks = spks.into_iter();
-            let mut last_index = Option::<u32>::None;
-            let mut last_active_index = Option::<u32>::None;
+/// Fetch latest blocks from Esplora in an atomic call.
+///
+/// We want to do this before fetching transactions and anchors as we cannot fetch latest blocks AND
+/// transactions atomically, and the checkpoint tip is used to determine last-scanned block (for
+/// block-based chain-sources). Therefore it's better to be conservative when setting the tip (use
+/// an earlier tip rather than a later tip) otherwise the caller may accidentally skip blocks when
+/// alternating between chain-sources.
+async fn fetch_latest_blocks(
+    client: &esplora_client::AsyncClient,
+) -> Result<BTreeMap<u32, BlockHash>, Error> {
+    Ok(client
+        .get_blocks(None)
+        .await?
+        .into_iter()
+        .map(|b| (b.time.height, b.id))
+        .collect())
+}
 
-            loop {
-                let handles = spks
-                    .by_ref()
-                    .take(parallel_requests)
-                    .map(|(spk_index, spk)| {
-                        let client = self.clone();
-                        async move {
-                            let mut last_seen = None;
-                            let mut spk_txs = Vec::new();
-                            loop {
-                                let txs = client.scripthash_txs(&spk, last_seen).await?;
-                                let tx_count = txs.len();
-                                last_seen = txs.last().map(|tx| tx.txid);
-                                spk_txs.extend(txs);
-                                if tx_count < 25 {
-                                    break Result::<_, Error>::Ok((spk_index, spk_txs));
-                                }
-                            }
-                        }
-                    })
-                    .collect::<FuturesOrdered<_>>();
+/// Used instead of [`esplora_client::BlockingClient::get_block_hash`].
+///
+/// This first checks the previously fetched `latest_blocks` before fetching from Esplora again.
+async fn fetch_block(
+    client: &esplora_client::AsyncClient,
+    latest_blocks: &BTreeMap<u32, BlockHash>,
+    height: u32,
+) -> Result<Option<BlockHash>, Error> {
+    if let Some(&hash) = latest_blocks.get(&height) {
+        return Ok(Some(hash));
+    }
 
-                if handles.is_empty() {
-                    break;
-                }
+    // We avoid fetching blocks higher than previously fetched `latest_blocks` as the local chain
+    // tip is used to signal for the last-synced-up-to-height.
+    let &tip_height = latest_blocks
+        .keys()
+        .last()
+        .expect("must have atleast one entry");
+    if height > tip_height {
+        return Ok(None);
+    }
 
-                for (index, txs) in handles.try_collect::<Vec<TxsOfSpkIndex>>().await? {
-                    last_index = Some(index);
-                    if !txs.is_empty() {
-                        last_active_index = Some(index);
-                    }
-                    for tx in txs {
-                        let _ = graph.insert_tx(tx.to_tx());
-                        if let Some(anchor) = anchor_from_status(&tx.status) {
-                            let _ = graph.insert_anchor(tx.txid, anchor);
-                        }
-                    }
-                }
+    Ok(Some(client.get_block_hash(height).await?))
+}
 
-                let last_index = last_index.expect("Must be set since handles wasn't empty.");
-                let past_gap_limit = if let Some(i) = last_active_index {
-                    last_index > i.saturating_add(stop_gap as u32)
-                } else {
-                    last_index >= stop_gap as u32
-                };
-                if past_gap_limit {
-                    break;
-                }
-            }
-
-            if let Some(last_active_index) = last_active_index {
-                last_active_indexes.insert(keychain, last_active_index);
-            }
+/// Create the [`local_chain::Update`].
+///
+/// We want to have a corresponding checkpoint per anchor height. However, checkpoints fetched
+/// should not surpass `latest_blocks`.
+async fn chain_update<A: Anchor>(
+    client: &esplora_client::AsyncClient,
+    latest_blocks: &BTreeMap<u32, BlockHash>,
+    local_tip: &CheckPoint,
+    anchors: &BTreeSet<(A, Txid)>,
+) -> Result<CheckPoint, Error> {
+    let mut point_of_agreement = None;
+    let mut conflicts = vec![];
+    for local_cp in local_tip.iter() {
+        let remote_hash = match fetch_block(client, latest_blocks, local_cp.height()).await? {
+            Some(hash) => hash,
+            None => continue,
+        };
+        if remote_hash == local_cp.hash() {
+            point_of_agreement = Some(local_cp.clone());
+            break;
+        } else {
+            // it is not strictly necessary to include all the conflicted heights (we do need the
+            // first one) but it seems prudent to make sure the updated chain's heights are a
+            // superset of the existing chain after update.
+            conflicts.push(BlockId {
+                height: local_cp.height(),
+                hash: remote_hash,
+            });
         }
+    }
+
+    let mut tip = point_of_agreement.expect("remote esplora should have same genesis block");
+
+    tip = tip
+        .extend(conflicts.into_iter().rev())
+        .expect("evicted are in order");
+
+    for anchor in anchors {
+        let height = anchor.0.anchor_block().height;
+        if tip.get(height).is_none() {
+            let hash = match fetch_block(client, latest_blocks, height).await? {
+                Some(hash) => hash,
+                None => continue,
+            };
+            tip = tip.insert(BlockId { height, hash });
+        }
+    }
+
+    // insert the most recent blocks at the tip to make sure we update the tip and make the update
+    // robust.
+    for (&height, &hash) in latest_blocks.iter() {
+        tip = tip.insert(BlockId { height, hash });
+    }
+
+    Ok(tip)
+}
+
+/// This performs a full scan to get an update for the [`TxGraph`] and
+/// [`KeychainTxOutIndex`](bdk_chain::keychain::KeychainTxOutIndex).
+async fn full_scan_for_index_and_graph<K: Ord + Clone + Send>(
+    client: &esplora_client::AsyncClient,
+    keychain_spks: BTreeMap<
+        K,
+        impl IntoIterator<IntoIter = impl Iterator<Item = (u32, ScriptBuf)> + Send> + Send,
+    >,
+    stop_gap: usize,
+    parallel_requests: usize,
+) -> Result<(TxGraph<ConfirmationTimeHeightAnchor>, BTreeMap<K, u32>), Error> {
+    type TxsOfSpkIndex = (u32, Vec<esplora_client::Tx>);
+    let parallel_requests = Ord::max(parallel_requests, 1);
+    let mut graph = TxGraph::<ConfirmationTimeHeightAnchor>::default();
+    let mut last_active_indexes = BTreeMap::<K, u32>::new();
+
+    for (keychain, spks) in keychain_spks {
+        let mut spks = spks.into_iter();
+        let mut last_index = Option::<u32>::None;
+        let mut last_active_index = Option::<u32>::None;
 
-        let mut txids = txids.into_iter();
         loop {
-            let handles = txids
+            let handles = spks
                 .by_ref()
                 .take(parallel_requests)
-                .filter(|&txid| graph.get_tx(txid).is_none())
-                .map(|txid| {
-                    let client = self.clone();
-                    async move { client.get_tx_status(&txid).await.map(|s| (txid, s)) }
+                .map(|(spk_index, spk)| {
+                    let client = client.clone();
+                    async move {
+                        let mut last_seen = None;
+                        let mut spk_txs = Vec::new();
+                        loop {
+                            let txs = client.scripthash_txs(&spk, last_seen).await?;
+                            let tx_count = txs.len();
+                            last_seen = txs.last().map(|tx| tx.txid);
+                            spk_txs.extend(txs);
+                            if tx_count < 25 {
+                                break Result::<_, Error>::Ok((spk_index, spk_txs));
+                            }
+                        }
+                    }
                 })
                 .collect::<FuturesOrdered<_>>();
 
@@ -291,39 +277,314 @@ impl EsploraAsyncExt for esplora_client::AsyncClient {
                 break;
             }
 
-            for (txid, status) in handles.try_collect::<Vec<(Txid, TxStatus)>>().await? {
-                if let Some(anchor) = anchor_from_status(&status) {
-                    let _ = graph.insert_anchor(txid, anchor);
+            for (index, txs) in handles.try_collect::<Vec<TxsOfSpkIndex>>().await? {
+                last_index = Some(index);
+                if !txs.is_empty() {
+                    last_active_index = Some(index);
                 }
+                for tx in txs {
+                    let _ = graph.insert_tx(tx.to_tx());
+                    if let Some(anchor) = anchor_from_status(&tx.status) {
+                        let _ = graph.insert_anchor(tx.txid, anchor);
+                    }
+
+                    let previous_outputs = tx.vin.iter().filter_map(|vin| {
+                        let prevout = vin.prevout.as_ref()?;
+                        Some((
+                            OutPoint {
+                                txid: vin.txid,
+                                vout: vin.vout,
+                            },
+                            TxOut {
+                                script_pubkey: prevout.scriptpubkey.clone(),
+                                value: Amount::from_sat(prevout.value),
+                            },
+                        ))
+                    });
+
+                    for (outpoint, txout) in previous_outputs {
+                        let _ = graph.insert_txout(outpoint, txout);
+                    }
+                }
+            }
+
+            let last_index = last_index.expect("Must be set since handles wasn't empty.");
+            let gap_limit_reached = if let Some(i) = last_active_index {
+                last_index >= i.saturating_add(stop_gap as u32)
+            } else {
+                last_index + 1 >= stop_gap as u32
+            };
+            if gap_limit_reached {
+                break;
             }
         }
 
-        for op in outpoints.into_iter() {
-            if graph.get_tx(op.txid).is_none() {
-                if let Some(tx) = self.get_tx(&op.txid).await? {
-                    let _ = graph.insert_tx(tx);
-                }
-                let status = self.get_tx_status(&op.txid).await?;
-                if let Some(anchor) = anchor_from_status(&status) {
-                    let _ = graph.insert_anchor(op.txid, anchor);
-                }
-            }
+        if let Some(last_active_index) = last_active_index {
+            last_active_indexes.insert(keychain, last_active_index);
+        }
+    }
 
-            if let Some(op_status) = self.get_output_status(&op.txid, op.vout as _).await? {
-                if let Some(txid) = op_status.txid {
-                    if graph.get_tx(txid).is_none() {
-                        if let Some(tx) = self.get_tx(&txid).await? {
-                            let _ = graph.insert_tx(tx);
-                        }
-                        let status = self.get_tx_status(&txid).await?;
-                        if let Some(anchor) = anchor_from_status(&status) {
-                            let _ = graph.insert_anchor(txid, anchor);
-                        }
+    Ok((graph, last_active_indexes))
+}
+
+async fn sync_for_index_and_graph(
+    client: &esplora_client::AsyncClient,
+    misc_spks: impl IntoIterator<IntoIter = impl Iterator<Item = ScriptBuf> + Send> + Send,
+    txids: impl IntoIterator<IntoIter = impl Iterator<Item = Txid> + Send> + Send,
+    outpoints: impl IntoIterator<IntoIter = impl Iterator<Item = OutPoint> + Send> + Send,
+    parallel_requests: usize,
+) -> Result<TxGraph<ConfirmationTimeHeightAnchor>, Error> {
+    let mut graph = full_scan_for_index_and_graph(
+        client,
+        [(
+            (),
+            misc_spks
+                .into_iter()
+                .enumerate()
+                .map(|(i, spk)| (i as u32, spk)),
+        )]
+        .into(),
+        usize::MAX,
+        parallel_requests,
+    )
+    .await
+    .map(|(g, _)| g)?;
+
+    let mut txids = txids.into_iter();
+    loop {
+        let handles = txids
+            .by_ref()
+            .take(parallel_requests)
+            .filter(|&txid| graph.get_tx(txid).is_none())
+            .map(|txid| {
+                let client = client.clone();
+                async move { client.get_tx_status(&txid).await.map(|s| (txid, s)) }
+            })
+            .collect::<FuturesOrdered<_>>();
+
+        if handles.is_empty() {
+            break;
+        }
+
+        for (txid, status) in handles.try_collect::<Vec<(Txid, TxStatus)>>().await? {
+            if let Some(anchor) = anchor_from_status(&status) {
+                let _ = graph.insert_anchor(txid, anchor);
+            }
+        }
+    }
+
+    for op in outpoints.into_iter() {
+        if graph.get_tx(op.txid).is_none() {
+            if let Some(tx) = client.get_tx(&op.txid).await? {
+                let _ = graph.insert_tx(tx);
+            }
+            let status = client.get_tx_status(&op.txid).await?;
+            if let Some(anchor) = anchor_from_status(&status) {
+                let _ = graph.insert_anchor(op.txid, anchor);
+            }
+        }
+
+        if let Some(op_status) = client.get_output_status(&op.txid, op.vout as _).await? {
+            if let Some(txid) = op_status.txid {
+                if graph.get_tx(txid).is_none() {
+                    if let Some(tx) = client.get_tx(&txid).await? {
+                        let _ = graph.insert_tx(tx);
+                    }
+                    let status = client.get_tx_status(&txid).await?;
+                    if let Some(anchor) = anchor_from_status(&status) {
+                        let _ = graph.insert_anchor(txid, anchor);
                     }
                 }
             }
         }
+    }
 
-        Ok((graph, last_active_indexes))
+    Ok(graph)
+}
+
+#[cfg(test)]
+mod test {
+    use std::{collections::BTreeSet, time::Duration};
+
+    use bdk_chain::{
+        bitcoin::{hashes::Hash, Txid},
+        local_chain::LocalChain,
+        BlockId,
+    };
+    use bdk_testenv::{anyhow, bitcoincore_rpc::RpcApi, TestEnv};
+    use esplora_client::Builder;
+
+    use crate::async_ext::{chain_update, fetch_latest_blocks};
+
+    macro_rules! h {
+        ($index:literal) => {{
+            bdk_chain::bitcoin::hashes::Hash::hash($index.as_bytes())
+        }};
+    }
+
+    /// Ensure that update does not remove heights (from original), and all anchor heights are included.
+    #[tokio::test]
+    pub async fn test_finalize_chain_update() -> anyhow::Result<()> {
+        struct TestCase<'a> {
+            name: &'a str,
+            /// Initial blockchain height to start the env with.
+            initial_env_height: u32,
+            /// Initial checkpoint heights to start with.
+            initial_cps: &'a [u32],
+            /// The final blockchain height of the env.
+            final_env_height: u32,
+            /// The anchors to test with: `(height, txid)`. Only the height is provided as we can fetch
+            /// the blockhash from the env.
+            anchors: &'a [(u32, Txid)],
+        }
+
+        let test_cases = [
+            TestCase {
+                name: "chain_extends",
+                initial_env_height: 60,
+                initial_cps: &[59, 60],
+                final_env_height: 90,
+                anchors: &[],
+            },
+            TestCase {
+                name: "introduce_older_heights",
+                initial_env_height: 50,
+                initial_cps: &[10, 15],
+                final_env_height: 50,
+                anchors: &[(11, h!("A")), (14, h!("B"))],
+            },
+            TestCase {
+                name: "introduce_older_heights_after_chain_extends",
+                initial_env_height: 50,
+                initial_cps: &[10, 15],
+                final_env_height: 100,
+                anchors: &[(11, h!("A")), (14, h!("B"))],
+            },
+        ];
+
+        for (i, t) in test_cases.into_iter().enumerate() {
+            println!("[{}] running test case: {}", i, t.name);
+
+            let env = TestEnv::new()?;
+            let base_url = format!("http://{}", &env.electrsd.esplora_url.clone().unwrap());
+            let client = Builder::new(base_url.as_str()).build_async()?;
+
+            // set env to `initial_env_height`
+            if let Some(to_mine) = t
+                .initial_env_height
+                .checked_sub(env.make_checkpoint_tip().height())
+            {
+                env.mine_blocks(to_mine as _, None)?;
+            }
+            while client.get_height().await? < t.initial_env_height {
+                std::thread::sleep(Duration::from_millis(10));
+            }
+
+            // craft initial `local_chain`
+            let local_chain = {
+                let (mut chain, _) = LocalChain::from_genesis_hash(env.genesis_hash()?);
+                // force `chain_update_blocking` to add all checkpoints in `t.initial_cps`
+                let anchors = t
+                    .initial_cps
+                    .iter()
+                    .map(|&height| -> anyhow::Result<_> {
+                        Ok((
+                            BlockId {
+                                height,
+                                hash: env.bitcoind.client.get_block_hash(height as _)?,
+                            },
+                            Txid::all_zeros(),
+                        ))
+                    })
+                    .collect::<anyhow::Result<BTreeSet<_>>>()?;
+                let update = chain_update(
+                    &client,
+                    &fetch_latest_blocks(&client).await?,
+                    &chain.tip(),
+                    &anchors,
+                )
+                .await?;
+                chain.apply_update(update)?;
+                chain
+            };
+            println!("local chain height: {}", local_chain.tip().height());
+
+            // extend env chain
+            if let Some(to_mine) = t
+                .final_env_height
+                .checked_sub(env.make_checkpoint_tip().height())
+            {
+                env.mine_blocks(to_mine as _, None)?;
+            }
+            while client.get_height().await? < t.final_env_height {
+                std::thread::sleep(Duration::from_millis(10));
+            }
+
+            // craft update
+            let update = {
+                let anchors = t
+                    .anchors
+                    .iter()
+                    .map(|&(height, txid)| -> anyhow::Result<_> {
+                        Ok((
+                            BlockId {
+                                height,
+                                hash: env.bitcoind.client.get_block_hash(height as _)?,
+                            },
+                            txid,
+                        ))
+                    })
+                    .collect::<anyhow::Result<_>>()?;
+                chain_update(
+                    &client,
+                    &fetch_latest_blocks(&client).await?,
+                    &local_chain.tip(),
+                    &anchors,
+                )
+                .await?
+            };
+
+            // apply update
+            let mut updated_local_chain = local_chain.clone();
+            updated_local_chain.apply_update(update)?;
+            println!(
+                "updated local chain height: {}",
+                updated_local_chain.tip().height()
+            );
+
+            assert!(
+                {
+                    let initial_heights = local_chain
+                        .iter_checkpoints()
+                        .map(|cp| cp.height())
+                        .collect::<BTreeSet<_>>();
+                    let updated_heights = updated_local_chain
+                        .iter_checkpoints()
+                        .map(|cp| cp.height())
+                        .collect::<BTreeSet<_>>();
+                    updated_heights.is_superset(&initial_heights)
+                },
+                "heights from the initial chain must all be in the updated chain",
+            );
+
+            assert!(
+                {
+                    let exp_anchor_heights = t
+                        .anchors
+                        .iter()
+                        .map(|(h, _)| *h)
+                        .chain(t.initial_cps.iter().copied())
+                        .collect::<BTreeSet<_>>();
+                    let anchor_heights = updated_local_chain
+                        .iter_checkpoints()
+                        .map(|cp| cp.height())
+                        .collect::<BTreeSet<_>>();
+                    anchor_heights.is_superset(&exp_anchor_heights)
+                },
+                "anchor heights must all be in updated chain",
+            );
+        }
+
+        Ok(())
     }
 }

crates/esplora/src/lib.rs

@@ -1,4 +1,21 @@
 #![doc = include_str!("../README.md")]
+
+//! This crate is used for updating structures of [`bdk_chain`] with data from an Esplora server.
+//!
+//! The two primary methods are [`EsploraExt::sync`] and [`EsploraExt::full_scan`]. In most cases
+//! [`EsploraExt::sync`] is used to sync the transaction histories of scripts that the application
+//! cares about, for example the scripts for all the receive addresses of a Wallet's keychain that it
+//! has shown a user. [`EsploraExt::full_scan`] is meant to be used when importing or restoring a
+//! keychain where the range of possibly used scripts is not known. In this case it is necessary to
+//! scan all keychain scripts until a number (the "stop gap") of unused scripts is discovered. For a
+//! sync or full scan the user receives relevant blockchain data and output updates for [`bdk_chain`]
+//! via a new [`TxGraph`] to be appended to any existing [`TxGraph`] data.
+//!
+//! Refer to [`example_esplora`] for a complete example.
+//!
+//! [`TxGraph`]: bdk_chain::tx_graph::TxGraph
+//! [`example_esplora`]: https://github.com/bitcoindevkit/bdk/tree/master/example-crates/example_esplora
+
 use bdk_chain::{BlockId, ConfirmationTimeHeightAnchor};
 use esplora_client::TxStatus;
 
@@ -14,8 +31,6 @@ mod async_ext;
 #[cfg(feature = "async")]
 pub use async_ext::*;
 
-const ASSUME_FINAL_DEPTH: u32 = 15;
-
 fn anchor_from_status(status: &TxStatus) -> Option<ConfirmationTimeHeightAnchor> {
     if let TxStatus {
         block_height: Some(height),

crates/esplora/tests/async_ext.rs

@@ -1,68 +1,20 @@
+use bdk_chain::spk_client::{FullScanRequest, SyncRequest};
 use bdk_esplora::EsploraAsyncExt;
-use electrsd::bitcoind::bitcoincore_rpc::RpcApi;
-use electrsd::bitcoind::{self, anyhow, BitcoinD};
-use electrsd::{Conf, ElectrsD};
-use esplora_client::{self, AsyncClient, Builder};
-use std::collections::{BTreeMap, HashSet};
+use esplora_client::{self, Builder};
+use std::collections::{BTreeSet, HashSet};
 use std::str::FromStr;
 use std::thread::sleep;
 use std::time::Duration;
 
-use bdk_chain::bitcoin::{Address, Amount, BlockHash, Txid};
-
-struct TestEnv {
-    bitcoind: BitcoinD,
-    #[allow(dead_code)]
-    electrsd: ElectrsD,
-    client: AsyncClient,
-}
-
-impl TestEnv {
-    fn new() -> Result<Self, anyhow::Error> {
-        let bitcoind_exe =
-            bitcoind::downloaded_exe_path().expect("bitcoind version feature must be enabled");
-        let bitcoind = BitcoinD::new(bitcoind_exe).unwrap();
-
-        let mut electrs_conf = Conf::default();
-        electrs_conf.http_enabled = true;
-        let electrs_exe =
-            electrsd::downloaded_exe_path().expect("electrs version feature must be enabled");
-        let electrsd = ElectrsD::with_conf(electrs_exe, &bitcoind, &electrs_conf)?;
-
-        let base_url = format!("http://{}", &electrsd.esplora_url.clone().unwrap());
-        let client = Builder::new(base_url.as_str()).build_async()?;
-
-        Ok(Self {
-            bitcoind,
-            electrsd,
-            client,
-        })
-    }
-
-    fn mine_blocks(
-        &self,
-        count: usize,
-        address: Option<Address>,
-    ) -> anyhow::Result<Vec<BlockHash>> {
-        let coinbase_address = match address {
-            Some(address) => address,
-            None => self
-                .bitcoind
-                .client
-                .get_new_address(None, None)?
-                .assume_checked(),
-        };
-        let block_hashes = self
-            .bitcoind
-            .client
-            .generate_to_address(count as _, &coinbase_address)?;
-        Ok(block_hashes)
-    }
-}
+use bdk_chain::bitcoin::{Address, Amount, Txid};
+use bdk_testenv::{anyhow, bitcoincore_rpc::RpcApi, TestEnv};
 
 #[tokio::test]
 pub async fn test_update_tx_graph_without_keychain() -> anyhow::Result<()> {
     let env = TestEnv::new()?;
+    let base_url = format!("http://{}", &env.electrsd.esplora_url.clone().unwrap());
+    let client = Builder::new(base_url.as_str()).build_async()?;
+
     let receive_address0 =
         Address::from_str("bcrt1qc6fweuf4xjvz4x3gx3t9e0fh4hvqyu2qw4wvxm")?.assume_checked();
     let receive_address1 =
@@ -95,19 +47,56 @@ pub async fn test_update_tx_graph_without_keychain() -> anyhow::Result<()> {
         None,
     )?;
     let _block_hashes = env.mine_blocks(1, None)?;
-    while env.client.get_height().await.unwrap() < 102 {
+    while client.get_height().await.unwrap() < 102 {
         sleep(Duration::from_millis(10))
     }
 
-    let graph_update = env
-        .client
-        .scan_txs(
-            misc_spks.into_iter(),
-            vec![].into_iter(),
-            vec![].into_iter(),
-            1,
-        )
-        .await?;
+    // use a full checkpoint linked list (since this is not what we are testing)
+    let cp_tip = env.make_checkpoint_tip();
+
+    let sync_update = {
+        let request = SyncRequest::from_chain_tip(cp_tip.clone()).set_spks(misc_spks);
+        client.sync(request, 1).await?
+    };
+
+    assert!(
+        {
+            let update_cps = sync_update
+                .chain_update
+                .iter()
+                .map(|cp| cp.block_id())
+                .collect::<BTreeSet<_>>();
+            let superset_cps = cp_tip
+                .iter()
+                .map(|cp| cp.block_id())
+                .collect::<BTreeSet<_>>();
+            superset_cps.is_superset(&update_cps)
+        },
+        "update should not alter original checkpoint tip since we already started with all checkpoints",
+    );
+
+    let graph_update = sync_update.graph_update;
+    // Check to see if we have the floating txouts available from our two created transactions'
+    // previous outputs in order to calculate transaction fees.
+    for tx in graph_update.full_txs() {
+        // Retrieve the calculated fee from `TxGraph`, which will panic if we do not have the
+        // floating txouts available from the transactions' previous outputs.
+        let fee = graph_update.calculate_fee(&tx.tx).expect("Fee must exist");
+
+        // Retrieve the fee in the transaction data from `bitcoind`.
+        let tx_fee = env
+            .bitcoind
+            .client
+            .get_transaction(&tx.txid, None)
+            .expect("Tx must exist")
+            .fee
+            .expect("Fee must exist")
+            .abs()
+            .to_sat() as u64;
+
+        // Check that the calculated fee matches the fee from the transaction data.
+        assert_eq!(fee, tx_fee);
+    }
 
     let mut graph_update_txids: Vec<Txid> = graph_update.full_txs().map(|tx| tx.txid).collect();
     graph_update_txids.sort();
@@ -117,10 +106,12 @@ pub async fn test_update_tx_graph_without_keychain() -> anyhow::Result<()> {
     Ok(())
 }
 
-/// Test the bounds of the address scan depending on the gap limit.
+/// Test the bounds of the address scan depending on the `stop_gap`.
 #[tokio::test]
-pub async fn test_async_update_tx_graph_gap_limit() -> anyhow::Result<()> {
+pub async fn test_async_update_tx_graph_stop_gap() -> anyhow::Result<()> {
     let env = TestEnv::new()?;
+    let base_url = format!("http://{}", &env.electrsd.esplora_url.clone().unwrap());
+    let client = Builder::new(base_url.as_str()).build_async()?;
     let _block_hashes = env.mine_blocks(101, None)?;
 
     // Now let's test the gap limit. First of all get a chain of 10 addresses.
@@ -145,8 +136,6 @@ pub async fn test_async_update_tx_graph_gap_limit() -> anyhow::Result<()> {
         .enumerate()
         .map(|(i, addr)| (i as u32, addr.script_pubkey()))
         .collect();
-    let mut keychains = BTreeMap::new();
-    keychains.insert(0, spks);
 
     // Then receive coins on the 4th address.
     let txid_4th_addr = env.bitcoind.client.send_to_address(
@@ -160,36 +149,37 @@ pub async fn test_async_update_tx_graph_gap_limit() -> anyhow::Result<()> {
         None,
     )?;
     let _block_hashes = env.mine_blocks(1, None)?;
-    while env.client.get_height().await.unwrap() < 103 {
+    while client.get_height().await.unwrap() < 103 {
         sleep(Duration::from_millis(10))
     }
 
-    // A scan with a gap limit of 2 won't find the transaction, but a scan with a gap limit of 3
+    // use a full checkpoint linked list (since this is not what we are testing)
+    let cp_tip = env.make_checkpoint_tip();
+
+    // A scan with a gap limit of 3 won't find the transaction, but a scan with a gap limit of 4
     // will.
-    let (graph_update, active_indices) = env
-        .client
-        .scan_txs_with_keychains(
-            keychains.clone(),
-            vec![].into_iter(),
-            vec![].into_iter(),
-            2,
-            1,
-        )
-        .await?;
-    assert!(graph_update.full_txs().next().is_none());
-    assert!(active_indices.is_empty());
-    let (graph_update, active_indices) = env
-        .client
-        .scan_txs_with_keychains(
-            keychains.clone(),
-            vec![].into_iter(),
-            vec![].into_iter(),
-            3,
-            1,
-        )
-        .await?;
-    assert_eq!(graph_update.full_txs().next().unwrap().txid, txid_4th_addr);
-    assert_eq!(active_indices[&0], 3);
+    let full_scan_update = {
+        let request =
+            FullScanRequest::from_chain_tip(cp_tip.clone()).set_spks_for_keychain(0, spks.clone());
+        client.full_scan(request, 3, 1).await?
+    };
+    assert!(full_scan_update.graph_update.full_txs().next().is_none());
+    assert!(full_scan_update.last_active_indices.is_empty());
+    let full_scan_update = {
+        let request =
+            FullScanRequest::from_chain_tip(cp_tip.clone()).set_spks_for_keychain(0, spks.clone());
+        client.full_scan(request, 4, 1).await?
+    };
+    assert_eq!(
+        full_scan_update
+            .graph_update
+            .full_txs()
+            .next()
+            .unwrap()
+            .txid,
+        txid_4th_addr
+    );
+    assert_eq!(full_scan_update.last_active_indices[&0], 3);
 
     // Now receive a coin on the last address.
     let txid_last_addr = env.bitcoind.client.send_to_address(
@@ -203,34 +193,38 @@ pub async fn test_async_update_tx_graph_gap_limit() -> anyhow::Result<()> {
         None,
     )?;
     let _block_hashes = env.mine_blocks(1, None)?;
-    while env.client.get_height().await.unwrap() < 104 {
+    while client.get_height().await.unwrap() < 104 {
         sleep(Duration::from_millis(10))
     }
 
-    // A scan with gap limit 4 won't find the second transaction, but a scan with gap limit 5 will.
+    // A scan with gap limit 5 won't find the second transaction, but a scan with gap limit 6 will.
     // The last active indice won't be updated in the first case but will in the second one.
-    let (graph_update, active_indices) = env
-        .client
-        .scan_txs_with_keychains(
-            keychains.clone(),
-            vec![].into_iter(),
-            vec![].into_iter(),
-            4,
-            1,
-        )
-        .await?;
-    let txs: HashSet<_> = graph_update.full_txs().map(|tx| tx.txid).collect();
+    let full_scan_update = {
+        let request =
+            FullScanRequest::from_chain_tip(cp_tip.clone()).set_spks_for_keychain(0, spks.clone());
+        client.full_scan(request, 5, 1).await?
+    };
+    let txs: HashSet<_> = full_scan_update
+        .graph_update
+        .full_txs()
+        .map(|tx| tx.txid)
+        .collect();
     assert_eq!(txs.len(), 1);
     assert!(txs.contains(&txid_4th_addr));
-    assert_eq!(active_indices[&0], 3);
-    let (graph_update, active_indices) = env
-        .client
-        .scan_txs_with_keychains(keychains, vec![].into_iter(), vec![].into_iter(), 5, 1)
-        .await?;
-    let txs: HashSet<_> = graph_update.full_txs().map(|tx| tx.txid).collect();
+    assert_eq!(full_scan_update.last_active_indices[&0], 3);
+    let full_scan_update = {
+        let request =
+            FullScanRequest::from_chain_tip(cp_tip.clone()).set_spks_for_keychain(0, spks.clone());
+        client.full_scan(request, 6, 1).await?
+    };
+    let txs: HashSet<_> = full_scan_update
+        .graph_update
+        .full_txs()
+        .map(|tx| tx.txid)
+        .collect();
     assert_eq!(txs.len(), 2);
     assert!(txs.contains(&txid_4th_addr) && txs.contains(&txid_last_addr));
-    assert_eq!(active_indices[&0], 9);
+    assert_eq!(full_scan_update.last_active_indices[&0], 9);
 
     Ok(())
 }

crates/esplora/tests/blocking_ext.rs

@@ -1,68 +1,20 @@
+use bdk_chain::spk_client::{FullScanRequest, SyncRequest};
 use bdk_esplora::EsploraExt;
-use electrsd::bitcoind::bitcoincore_rpc::RpcApi;
-use electrsd::bitcoind::{self, anyhow, BitcoinD};
-use electrsd::{Conf, ElectrsD};
-use esplora_client::{self, BlockingClient, Builder};
-use std::collections::{BTreeMap, HashSet};
+use esplora_client::{self, Builder};
+use std::collections::{BTreeSet, HashSet};
 use std::str::FromStr;
 use std::thread::sleep;
 use std::time::Duration;
 
-use bdk_chain::bitcoin::{Address, Amount, BlockHash, Txid};
-
-struct TestEnv {
-    bitcoind: BitcoinD,
-    #[allow(dead_code)]
-    electrsd: ElectrsD,
-    client: BlockingClient,
-}
-
-impl TestEnv {
-    fn new() -> Result<Self, anyhow::Error> {
-        let bitcoind_exe =
-            bitcoind::downloaded_exe_path().expect("bitcoind version feature must be enabled");
-        let bitcoind = BitcoinD::new(bitcoind_exe).unwrap();
-
-        let mut electrs_conf = Conf::default();
-        electrs_conf.http_enabled = true;
-        let electrs_exe =
-            electrsd::downloaded_exe_path().expect("electrs version feature must be enabled");
-        let electrsd = ElectrsD::with_conf(electrs_exe, &bitcoind, &electrs_conf)?;
-
-        let base_url = format!("http://{}", &electrsd.esplora_url.clone().unwrap());
-        let client = Builder::new(base_url.as_str()).build_blocking()?;
-
-        Ok(Self {
-            bitcoind,
-            electrsd,
-            client,
-        })
-    }
-
-    fn mine_blocks(
-        &self,
-        count: usize,
-        address: Option<Address>,
-    ) -> anyhow::Result<Vec<BlockHash>> {
-        let coinbase_address = match address {
-            Some(address) => address,
-            None => self
-                .bitcoind
-                .client
-                .get_new_address(None, None)?
-                .assume_checked(),
-        };
-        let block_hashes = self
-            .bitcoind
-            .client
-            .generate_to_address(count as _, &coinbase_address)?;
-        Ok(block_hashes)
-    }
-}
+use bdk_chain::bitcoin::{Address, Amount, Txid};
+use bdk_testenv::{anyhow, bitcoincore_rpc::RpcApi, TestEnv};
 
 #[test]
 pub fn test_update_tx_graph_without_keychain() -> anyhow::Result<()> {
     let env = TestEnv::new()?;
+    let base_url = format!("http://{}", &env.electrsd.esplora_url.clone().unwrap());
+    let client = Builder::new(base_url.as_str()).build_blocking();
+
     let receive_address0 =
         Address::from_str("bcrt1qc6fweuf4xjvz4x3gx3t9e0fh4hvqyu2qw4wvxm")?.assume_checked();
     let receive_address1 =
@@ -95,16 +47,56 @@ pub fn test_update_tx_graph_without_keychain() -> anyhow::Result<()> {
         None,
     )?;
     let _block_hashes = env.mine_blocks(1, None)?;
-    while env.client.get_height().unwrap() < 102 {
+    while client.get_height().unwrap() < 102 {
         sleep(Duration::from_millis(10))
     }
 
-    let graph_update = env.client.scan_txs(
-        misc_spks.into_iter(),
-        vec![].into_iter(),
-        vec![].into_iter(),
-        1,
-    )?;
+    // use a full checkpoint linked list (since this is not what we are testing)
+    let cp_tip = env.make_checkpoint_tip();
+
+    let sync_update = {
+        let request = SyncRequest::from_chain_tip(cp_tip.clone()).set_spks(misc_spks);
+        client.sync(request, 1)?
+    };
+
+    assert!(
+        {
+            let update_cps = sync_update
+                .chain_update
+                .iter()
+                .map(|cp| cp.block_id())
+                .collect::<BTreeSet<_>>();
+            let superset_cps = cp_tip
+                .iter()
+                .map(|cp| cp.block_id())
+                .collect::<BTreeSet<_>>();
+            superset_cps.is_superset(&update_cps)
+        },
+        "update should not alter original checkpoint tip since we already started with all checkpoints",
+    );
+
+    let graph_update = sync_update.graph_update;
+    // Check to see if we have the floating txouts available from our two created transactions'
+    // previous outputs in order to calculate transaction fees.
+    for tx in graph_update.full_txs() {
+        // Retrieve the calculated fee from `TxGraph`, which will panic if we do not have the
+        // floating txouts available from the transactions' previous outputs.
+        let fee = graph_update.calculate_fee(&tx.tx).expect("Fee must exist");
+
+        // Retrieve the fee in the transaction data from `bitcoind`.
+        let tx_fee = env
+            .bitcoind
+            .client
+            .get_transaction(&tx.txid, None)
+            .expect("Tx must exist")
+            .fee
+            .expect("Fee must exist")
+            .abs()
+            .to_sat() as u64;
+
+        // Check that the calculated fee matches the fee from the transaction data.
+        assert_eq!(fee, tx_fee);
+    }
 
     let mut graph_update_txids: Vec<Txid> = graph_update.full_txs().map(|tx| tx.txid).collect();
     graph_update_txids.sort();
@@ -115,10 +107,12 @@ pub fn test_update_tx_graph_without_keychain() -> anyhow::Result<()> {
     Ok(())
 }
 
-/// Test the bounds of the address scan depending on the gap limit.
+/// Test the bounds of the address scan depending on the `stop_gap`.
 #[test]
-pub fn test_update_tx_graph_gap_limit() -> anyhow::Result<()> {
+pub fn test_update_tx_graph_stop_gap() -> anyhow::Result<()> {
     let env = TestEnv::new()?;
+    let base_url = format!("http://{}", &env.electrsd.esplora_url.clone().unwrap());
+    let client = Builder::new(base_url.as_str()).build_blocking();
     let _block_hashes = env.mine_blocks(101, None)?;
 
     // Now let's test the gap limit. First of all get a chain of 10 addresses.
@@ -143,8 +137,6 @@ pub fn test_update_tx_graph_gap_limit() -> anyhow::Result<()> {
         .enumerate()
         .map(|(i, addr)| (i as u32, addr.script_pubkey()))
         .collect();
-    let mut keychains = BTreeMap::new();
-    keychains.insert(0, spks);
 
     // Then receive coins on the 4th address.
     let txid_4th_addr = env.bitcoind.client.send_to_address(
@@ -158,30 +150,37 @@ pub fn test_update_tx_graph_gap_limit() -> anyhow::Result<()> {
         None,
     )?;
     let _block_hashes = env.mine_blocks(1, None)?;
-    while env.client.get_height().unwrap() < 103 {
+    while client.get_height().unwrap() < 103 {
         sleep(Duration::from_millis(10))
     }
 
-    // A scan with a gap limit of 2 won't find the transaction, but a scan with a gap limit of 3
+    // use a full checkpoint linked list (since this is not what we are testing)
+    let cp_tip = env.make_checkpoint_tip();
+
+    // A scan with a stop_gap of 3 won't find the transaction, but a scan with a gap limit of 4
     // will.
-    let (graph_update, active_indices) = env.client.scan_txs_with_keychains(
-        keychains.clone(),
-        vec![].into_iter(),
-        vec![].into_iter(),
-        2,
-        1,
-    )?;
-    assert!(graph_update.full_txs().next().is_none());
-    assert!(active_indices.is_empty());
-    let (graph_update, active_indices) = env.client.scan_txs_with_keychains(
-        keychains.clone(),
-        vec![].into_iter(),
-        vec![].into_iter(),
-        3,
-        1,
-    )?;
-    assert_eq!(graph_update.full_txs().next().unwrap().txid, txid_4th_addr);
-    assert_eq!(active_indices[&0], 3);
+    let full_scan_update = {
+        let request =
+            FullScanRequest::from_chain_tip(cp_tip.clone()).set_spks_for_keychain(0, spks.clone());
+        client.full_scan(request, 3, 1)?
+    };
+    assert!(full_scan_update.graph_update.full_txs().next().is_none());
+    assert!(full_scan_update.last_active_indices.is_empty());
+    let full_scan_update = {
+        let request =
+            FullScanRequest::from_chain_tip(cp_tip.clone()).set_spks_for_keychain(0, spks.clone());
+        client.full_scan(request, 4, 1)?
+    };
+    assert_eq!(
+        full_scan_update
+            .graph_update
+            .full_txs()
+            .next()
+            .unwrap()
+            .txid,
+        txid_4th_addr
+    );
+    assert_eq!(full_scan_update.last_active_indices[&0], 3);
 
     // Now receive a coin on the last address.
     let txid_last_addr = env.bitcoind.client.send_to_address(
@@ -195,34 +194,38 @@ pub fn test_update_tx_graph_gap_limit() -> anyhow::Result<()> {
         None,
     )?;
     let _block_hashes = env.mine_blocks(1, None)?;
-    while env.client.get_height().unwrap() < 104 {
+    while client.get_height().unwrap() < 104 {
         sleep(Duration::from_millis(10))
     }
 
-    // A scan with gap limit 4 won't find the second transaction, but a scan with gap limit 5 will.
+    // A scan with gap limit 5 won't find the second transaction, but a scan with gap limit 6 will.
     // The last active indice won't be updated in the first case but will in the second one.
-    let (graph_update, active_indices) = env.client.scan_txs_with_keychains(
-        keychains.clone(),
-        vec![].into_iter(),
-        vec![].into_iter(),
-        4,
-        1,
-    )?;
-    let txs: HashSet<_> = graph_update.full_txs().map(|tx| tx.txid).collect();
+    let full_scan_update = {
+        let request =
+            FullScanRequest::from_chain_tip(cp_tip.clone()).set_spks_for_keychain(0, spks.clone());
+        client.full_scan(request, 5, 1)?
+    };
+    let txs: HashSet<_> = full_scan_update
+        .graph_update
+        .full_txs()
+        .map(|tx| tx.txid)
+        .collect();
     assert_eq!(txs.len(), 1);
     assert!(txs.contains(&txid_4th_addr));
-    assert_eq!(active_indices[&0], 3);
-    let (graph_update, active_indices) = env.client.scan_txs_with_keychains(
-        keychains,
-        vec![].into_iter(),
-        vec![].into_iter(),
-        5,
-        1,
-    )?;
-    let txs: HashSet<_> = graph_update.full_txs().map(|tx| tx.txid).collect();
+    assert_eq!(full_scan_update.last_active_indices[&0], 3);
+    let full_scan_update = {
+        let request =
+            FullScanRequest::from_chain_tip(cp_tip.clone()).set_spks_for_keychain(0, spks.clone());
+        client.full_scan(request, 6, 1)?
+    };
+    let txs: HashSet<_> = full_scan_update
+        .graph_update
+        .full_txs()
+        .map(|tx| tx.txid)
+        .collect();
     assert_eq!(txs.len(), 2);
     assert!(txs.contains(&txid_4th_addr) && txs.contains(&txid_last_addr));
-    assert_eq!(active_indices[&0], 9);
+    assert_eq!(full_scan_update.last_active_indices[&0], 9);
 
     Ok(())
 }

crates/file_store/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bdk_file_store"
-version = "0.2.0"
+version = "0.11.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/bitcoindevkit/bdk"
@@ -11,7 +11,9 @@ authors = ["Bitcoin Dev Kit Developers"]
 readme = "README.md"
 
 [dependencies]
-bdk_chain = { path = "../chain", version = "0.6.0", features = [ "serde", "miniscript" ] }
+anyhow = { version = "1", default-features = false }
+bdk_chain = { path = "../chain", version = "0.14.0", features = [ "serde", "miniscript" ] }
+bdk_persist = { path = "../persist", version = "0.2.0"}
 bincode = { version = "1" }
 serde = { version = "1", features = ["derive"] }
 

crates/file_store/README.md

@@ -1,10 +1,10 @@
 # BDK File Store
 
 This is a simple append-only flat file implementation of
-[`Persist`](`bdk_chain::Persist`).
+[`PersistBackend`](bdk_persist::PersistBackend).
 
-The main structure is [`Store`](`crate::Store`), which can be used with [`bdk`]'s
+The main structure is [`Store`](crate::Store), which can be used with [`bdk`]'s
 `Wallet` to persist wallet data into a flat file.
 
 [`bdk`]: https://docs.rs/bdk/latest
-[`bdk_chain`]: https://docs.rs/bdk_chain/latest
+[`bdk_persist`]: https://docs.rs/bdk_persist/latest

crates/file_store/src/entry_iter.rs

@@ -1,7 +1,7 @@
 use bincode::Options;
 use std::{
     fs::File,
-    io::{self, Seek},
+    io::{self, BufReader, Seek},
     marker::PhantomData,
 };
 
@@ -14,8 +14,9 @@ use crate::bincode_options;
 ///
 /// [`next`]: Self::next
 pub struct EntryIter<'t, T> {
-    db_file: Option<&'t mut File>,
-
+    /// Buffered reader around the file
+    db_file: BufReader<&'t mut File>,
+    finished: bool,
     /// The file position for the first read of `db_file`.
     start_pos: Option<u64>,
     types: PhantomData<T>,
@@ -24,8 +25,9 @@ pub struct EntryIter<'t, T> {
 impl<'t, T> EntryIter<'t, T> {
     pub fn new(start_pos: u64, db_file: &'t mut File) -> Self {
         Self {
-            db_file: Some(db_file),
+            db_file: BufReader::new(db_file),
             start_pos: Some(start_pos),
+            finished: false,
             types: PhantomData,
         }
     }
@@ -38,44 +40,44 @@ where
     type Item = Result<T, IterError>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        // closure which reads a single entry starting from `self.pos`
-        let read_one = |f: &mut File, start_pos: Option<u64>| -> Result<Option<T>, IterError> {
-            let pos = match start_pos {
-                Some(pos) => f.seek(io::SeekFrom::Start(pos))?,
-                None => f.stream_position()?,
-            };
+        if self.finished {
+            return None;
+        }
+        (|| {
+            if let Some(start) = self.start_pos.take() {
+                self.db_file.seek(io::SeekFrom::Start(start))?;
+            }
 
-            match bincode_options().deserialize_from(&*f) {
-                Ok(changeset) => {
-                    f.stream_position()?;
-                    Ok(Some(changeset))
-                }
+            let pos_before_read = self.db_file.stream_position()?;
+            match bincode_options().deserialize_from(&mut self.db_file) {
+                Ok(changeset) => Ok(Some(changeset)),
                 Err(e) => {
+                    self.finished = true;
+                    let pos_after_read = self.db_file.stream_position()?;
+                    // allow unexpected EOF if 0 bytes were read
                     if let bincode::ErrorKind::Io(inner) = &*e {
-                        if inner.kind() == io::ErrorKind::UnexpectedEof {
-                            let eof = f.seek(io::SeekFrom::End(0))?;
-                            if pos == eof {
-                                return Ok(None);
-                            }
+                        if inner.kind() == io::ErrorKind::UnexpectedEof
+                            && pos_after_read == pos_before_read
+                        {
+                            return Ok(None);
                         }
                     }
-                    f.seek(io::SeekFrom::Start(pos))?;
+                    self.db_file.seek(io::SeekFrom::Start(pos_before_read))?;
                     Err(IterError::Bincode(*e))
                 }
             }
-        };
-
-        let result = read_one(self.db_file.as_mut()?, self.start_pos.take());
-        if result.is_err() {
-            self.db_file = None;
-        }
-        result.transpose()
+        })()
+        .transpose()
     }
 }
 
-impl From<io::Error> for IterError {
-    fn from(value: io::Error) -> Self {
-        IterError::Io(value)
+impl<'t, T> Drop for EntryIter<'t, T> {
+    fn drop(&mut self) {
+        // This syncs the underlying file's offset with the buffer's position. This way, we
+        // maintain the correct position to start the next read/write.
+        if let Ok(pos) = self.db_file.stream_position() {
+            let _ = self.db_file.get_mut().seek(io::SeekFrom::Start(pos));
+        }
     }
 }
 
@@ -97,4 +99,10 @@ impl core::fmt::Display for IterError {
     }
 }
 
+impl From<io::Error> for IterError {
+    fn from(value: io::Error) -> Self {
+        IterError::Io(value)
+    }
+}
+
 impl std::error::Error for IterError {}

crates/file_store/src/lib.rs

@@ -13,14 +13,14 @@ pub(crate) fn bincode_options() -> impl bincode::Options {
 
 /// Error that occurs due to problems encountered with the file.
 #[derive(Debug)]
-pub enum FileError<'a> {
+pub enum FileError {
     /// IO error, this may mean that the file is too short.
     Io(io::Error),
     /// Magic bytes do not match what is expected.
-    InvalidMagicBytes { got: Vec<u8>, expected: &'a [u8] },
+    InvalidMagicBytes { got: Vec<u8>, expected: Vec<u8> },
 }
 
-impl<'a> core::fmt::Display for FileError<'a> {
+impl core::fmt::Display for FileError {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         match self {
             Self::Io(e) => write!(f, "io error trying to read file: {}", e),
@@ -33,10 +33,10 @@ impl<'a> core::fmt::Display for FileError<'a> {
     }
 }
 
-impl<'a> From<io::Error> for FileError<'a> {
+impl From<io::Error> for FileError {
     fn from(value: io::Error) -> Self {
         Self::Io(value)
     }
 }
 
-impl<'a> std::error::Error for FileError<'a> {}
+impl std::error::Error for FileError {}

crates/file_store/src/store.rs

@@ -1,46 +1,53 @@
+use crate::{bincode_options, EntryIter, FileError, IterError};
+use anyhow::anyhow;
+use bdk_chain::Append;
+use bdk_persist::PersistBackend;
+use bincode::Options;
 use std::{
-    fmt::Debug,
+    fmt::{self, Debug},
     fs::{File, OpenOptions},
     io::{self, Read, Seek, Write},
     marker::PhantomData,
     path::Path,
 };
 
-use bdk_chain::{Append, PersistBackend};
-use bincode::Options;
-
-use crate::{bincode_options, EntryIter, FileError, IterError};
-
 /// Persists an append-only list of changesets (`C`) to a single file.
-///
-/// The changesets are the results of altering a tracker implementation (`T`).
 #[derive(Debug)]
-pub struct Store<'a, C> {
-    magic: &'a [u8],
+pub struct Store<C>
+where
+    C: Sync + Send,
+{
+    magic_len: usize,
     db_file: File,
     marker: PhantomData<C>,
 }
 
-impl<'a, C> PersistBackend<C> for Store<'a, C>
+impl<C> PersistBackend<C> for Store<C>
 where
-    C: Append + serde::Serialize + serde::de::DeserializeOwned,
+    C: Append
+        + serde::Serialize
+        + serde::de::DeserializeOwned
+        + core::marker::Send
+        + core::marker::Sync,
 {
-    type WriteError = std::io::Error;
-
-    type LoadError = IterError;
-
-    fn write_changes(&mut self, changeset: &C) -> Result<(), Self::WriteError> {
+    fn write_changes(&mut self, changeset: &C) -> anyhow::Result<()> {
         self.append_changeset(changeset)
+            .map_err(|e| anyhow!(e).context("failed to write changes to persistence backend"))
     }
 
-    fn load_from_persistence(&mut self) -> Result<Option<C>, Self::LoadError> {
-        self.aggregate_changesets().map_err(|e| e.iter_error)
+    fn load_from_persistence(&mut self) -> anyhow::Result<Option<C>> {
+        self.aggregate_changesets()
+            .map_err(|e| anyhow!(e.iter_error).context("error loading from persistence backend"))
     }
 }
 
-impl<'a, C> Store<'a, C>
+impl<C> Store<C>
 where
-    C: Append + serde::Serialize + serde::de::DeserializeOwned,
+    C: Append
+        + serde::Serialize
+        + serde::de::DeserializeOwned
+        + core::marker::Send
+        + core::marker::Sync,
 {
     /// Create a new [`Store`] file in write-only mode; error if the file exists.
     ///
@@ -48,7 +55,7 @@ where
     /// the `Store` in the future with [`open`].
     ///
     /// [`open`]: Store::open
-    pub fn create_new<P>(magic: &'a [u8], file_path: P) -> Result<Self, FileError>
+    pub fn create_new<P>(magic: &[u8], file_path: P) -> Result<Self, FileError>
     where
         P: AsRef<Path>,
     {
@@ -64,10 +71,11 @@ where
             .create(true)
             .read(true)
             .write(true)
+            .truncate(true)
             .open(file_path)?;
         f.write_all(magic)?;
         Ok(Self {
-            magic,
+            magic_len: magic.len(),
             db_file: f,
             marker: Default::default(),
         })
@@ -83,7 +91,7 @@ where
     /// [`FileError::InvalidMagicBytes`] error variant will be returned.
     ///
     /// [`create_new`]: Store::create_new
-    pub fn open<P>(magic: &'a [u8], file_path: P) -> Result<Self, FileError>
+    pub fn open<P>(magic: &[u8], file_path: P) -> Result<Self, FileError>
     where
         P: AsRef<Path>,
     {
@@ -94,24 +102,24 @@ where
         if magic_buf != magic {
             return Err(FileError::InvalidMagicBytes {
                 got: magic_buf,
-                expected: magic,
+                expected: magic.to_vec(),
             });
         }
 
         Ok(Self {
-            magic,
+            magic_len: magic.len(),
             db_file: f,
             marker: Default::default(),
         })
     }
 
-    /// Attempt to open existing [`Store`] file; create it if the file is non-existant.
+    /// Attempt to open existing [`Store`] file; create it if the file is non-existent.
     ///
     /// Internally, this calls either [`open`] or [`create_new`].
     ///
     /// [`open`]: Store::open
     /// [`create_new`]: Store::create_new
-    pub fn open_or_create_new<P>(magic: &'a [u8], file_path: P) -> Result<Self, FileError>
+    pub fn open_or_create_new<P>(magic: &[u8], file_path: P) -> Result<Self, FileError>
     where
         P: AsRef<Path>,
     {
@@ -132,18 +140,18 @@ where
     /// always iterate over all entries until `None` is returned if you want your next write to go
     /// at the end; otherwise, you will write over existing entries.
     pub fn iter_changesets(&mut self) -> EntryIter<C> {
-        EntryIter::new(self.magic.len() as u64, &mut self.db_file)
+        EntryIter::new(self.magic_len as u64, &mut self.db_file)
     }
 
     /// Loads all the changesets that have been stored as one giant changeset.
     ///
-    /// This function returns a tuple of the aggregate changeset and a result that indicates
-    /// whether an error occurred while reading or deserializing one of the entries. If so the
-    /// changeset will consist of all of those it was able to read.
+    /// This function returns the aggregate changeset, or `None` if nothing was persisted.
+    /// If reading or deserializing any of the entries fails, an error is returned that
+    /// consists of all those it was able to read.
     ///
     /// You should usually check the error. In many applications, it may make sense to do a full
     /// wallet scan with a stop-gap after getting an error, since it is likely that one of the
-    /// changesets it was unable to read changed the derivation indices of the tracker.
+    /// changesets was unable to read changes of the derivation indices of a keychain.
     ///
     /// **WARNING**: This method changes the write position of the underlying file. The next
     /// changeset will be written over the erroring entry (or the end of the file if none existed).
@@ -181,7 +189,7 @@ where
         bincode_options()
             .serialize_into(&mut self.db_file, changeset)
             .map_err(|e| match *e {
-                bincode::ErrorKind::Io(inner) => inner,
+                bincode::ErrorKind::Io(error) => error,
                 unexpected_err => panic!("unexpected bincode error: {}", unexpected_err),
             })?;
 
@@ -211,7 +219,7 @@ impl<C> std::fmt::Display for AggregateChangesetsError<C> {
     }
 }
 
-impl<C: std::fmt::Debug> std::error::Error for AggregateChangesetsError<C> {}
+impl<C: fmt::Debug> std::error::Error for AggregateChangesetsError<C> {}
 
 #[cfg(test)]
 mod test {
@@ -219,6 +227,7 @@ mod test {
 
     use bincode::DefaultOptions;
     use std::{
+        collections::BTreeSet,
         io::{Read, Write},
         vec::Vec,
     };
@@ -228,10 +237,7 @@ mod test {
     const TEST_MAGIC_BYTES: [u8; TEST_MAGIC_BYTES_LEN] =
         [98, 100, 107, 102, 115, 49, 49, 49, 49, 49, 49, 49];
 
-    type TestChangeSet = Vec<String>;
-
-    #[derive(Debug)]
-    struct TestTracker;
+    type TestChangeSet = BTreeSet<String>;
 
     /// Check behavior of [`Store::create_new`] and [`Store::open`].
     #[test]
@@ -253,7 +259,7 @@ mod test {
     fn open_or_create_new() {
         let temp_dir = tempfile::tempdir().unwrap();
         let file_path = temp_dir.path().join("db_file");
-        let changeset = vec!["hello".to_string(), "world".to_string()];
+        let changeset = BTreeSet::from(["hello".to_string(), "world".to_string()]);
 
         {
             let mut db = Store::<TestChangeSet>::open_or_create_new(&TEST_MAGIC_BYTES, &file_path)
@@ -304,7 +310,7 @@ mod test {
         let mut data = [255_u8; 2000];
         data[..TEST_MAGIC_BYTES_LEN].copy_from_slice(&TEST_MAGIC_BYTES);
 
-        let changeset = vec!["one".into(), "two".into(), "three!".into()];
+        let changeset = TestChangeSet::from(["one".into(), "two".into(), "three!".into()]);
 
         let mut file = NamedTempFile::new().unwrap();
         file.write_all(&data).expect("should write");
@@ -340,4 +346,119 @@ mod test {
 
         assert_eq!(got_bytes, expected_bytes);
     }
+
+    #[test]
+    fn last_write_is_short() {
+        let temp_dir = tempfile::tempdir().unwrap();
+
+        let changesets = [
+            TestChangeSet::from(["1".into()]),
+            TestChangeSet::from(["2".into(), "3".into()]),
+            TestChangeSet::from(["4".into(), "5".into(), "6".into()]),
+        ];
+        let last_changeset = TestChangeSet::from(["7".into(), "8".into(), "9".into()]);
+        let last_changeset_bytes = bincode_options().serialize(&last_changeset).unwrap();
+
+        for short_write_len in 1..last_changeset_bytes.len() - 1 {
+            let file_path = temp_dir.path().join(format!("{}.dat", short_write_len));
+            println!("Test file: {:?}", file_path);
+
+            // simulate creating a file, writing data where the last write is incomplete
+            {
+                let mut db =
+                    Store::<TestChangeSet>::create_new(&TEST_MAGIC_BYTES, &file_path).unwrap();
+                for changeset in &changesets {
+                    db.append_changeset(changeset).unwrap();
+                }
+                // this is the incomplete write
+                db.db_file
+                    .write_all(&last_changeset_bytes[..short_write_len])
+                    .unwrap();
+            }
+
+            // load file again and aggregate changesets
+            // write the last changeset again (this time it succeeds)
+            {
+                let mut db = Store::<TestChangeSet>::open(&TEST_MAGIC_BYTES, &file_path).unwrap();
+                let err = db
+                    .aggregate_changesets()
+                    .expect_err("should return error as last read is short");
+                assert_eq!(
+                    err.changeset,
+                    changesets.iter().cloned().reduce(|mut acc, cs| {
+                        Append::append(&mut acc, cs);
+                        acc
+                    }),
+                    "should recover all changesets that are written in full",
+                );
+                db.db_file.write_all(&last_changeset_bytes).unwrap();
+            }
+
+            // load file again - this time we should successfully aggregate all changesets
+            {
+                let mut db = Store::<TestChangeSet>::open(&TEST_MAGIC_BYTES, &file_path).unwrap();
+                let aggregated_changesets = db
+                    .aggregate_changesets()
+                    .expect("aggregating all changesets should succeed");
+                assert_eq!(
+                    aggregated_changesets,
+                    changesets
+                        .iter()
+                        .cloned()
+                        .chain(core::iter::once(last_changeset.clone()))
+                        .reduce(|mut acc, cs| {
+                            Append::append(&mut acc, cs);
+                            acc
+                        }),
+                    "should recover all changesets",
+                );
+            }
+        }
+    }
+
+    #[test]
+    fn write_after_short_read() {
+        let temp_dir = tempfile::tempdir().unwrap();
+
+        let changesets = (0..20)
+            .map(|n| TestChangeSet::from([format!("{}", n)]))
+            .collect::<Vec<_>>();
+        let last_changeset = TestChangeSet::from(["last".into()]);
+
+        for read_count in 0..changesets.len() {
+            let file_path = temp_dir.path().join(format!("{}.dat", read_count));
+            println!("Test file: {:?}", file_path);
+
+            // First, we create the file with all the changesets!
+            let mut db = Store::<TestChangeSet>::create_new(&TEST_MAGIC_BYTES, &file_path).unwrap();
+            for changeset in &changesets {
+                db.append_changeset(changeset).unwrap();
+            }
+            drop(db);
+
+            // We re-open the file and read `read_count` number of changesets.
+            let mut db = Store::<TestChangeSet>::open(&TEST_MAGIC_BYTES, &file_path).unwrap();
+            let mut exp_aggregation = db
+                .iter_changesets()
+                .take(read_count)
+                .map(|r| r.expect("must read valid changeset"))
+                .fold(TestChangeSet::default(), |mut acc, v| {
+                    Append::append(&mut acc, v);
+                    acc
+                });
+            // We write after a short read.
+            db.write_changes(&last_changeset)
+                .expect("last write must succeed");
+            Append::append(&mut exp_aggregation, last_changeset.clone());
+            drop(db);
+
+            // We open the file again and check whether aggregate changeset is expected.
+            let aggregation = Store::<TestChangeSet>::open(&TEST_MAGIC_BYTES, &file_path)
+                .unwrap()
+                .aggregate_changesets()
+                .expect("must aggregate changesets")
+                .unwrap_or_default();
+            assert_eq!(aggregation, exp_aggregation);
+        }
+    }
 }

crates/hwi/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "bdk_hwi"
+version = "0.2.0"
+edition = "2021"
+homepage = "https://bitcoindevkit.org"
+repository = "https://github.com/bitcoindevkit/bdk"
+description = "Utilities to use bdk with hardware wallets"
+license = "MIT OR Apache-2.0"
+readme = "README.md"
+
+[dependencies]
+bdk = { path = "../bdk" }
+hwi = { version = "0.8.0", features = [ "miniscript"] }

crates/hwi/src/lib.rs

@@ -0,0 +1,41 @@
+//! HWI Signer
+//!
+//! This crate contains HWISigner, an implementation of a [`TransactionSigner`] to be
+//! used with hardware wallets.
+//! ```no_run
+//! # use bdk::bitcoin::Network;
+//! # use bdk::signer::SignerOrdering;
+//! # use bdk_hwi::HWISigner;
+//! # use bdk::{KeychainKind, SignOptions, Wallet};
+//! # use hwi::HWIClient;
+//! # use std::sync::Arc;
+//! #
+//! # fn main() -> Result<(), Box<dyn std::error::Error>> {
+//! let mut devices = HWIClient::enumerate()?;
+//! if devices.is_empty() {
+//!     panic!("No devices found!");
+//! }
+//! let first_device = devices.remove(0)?;
+//! let custom_signer = HWISigner::from_device(&first_device, Network::Testnet.into())?;
+//!
+//! # let mut wallet = Wallet::new_no_persist(
+//! #     "",
+//! #     None,
+//! #     Network::Testnet,
+//! # )?;
+//! #
+//! // Adding the hardware signer to the BDK wallet
+//! wallet.add_signer(
+//!     KeychainKind::External,
+//!     SignerOrdering(200),
+//!     Arc::new(custom_signer),
+//! );
+//!
+//! # Ok(())
+//! # }
+//! ```
+//!
+//! [`TransactionSigner`]: bdk::wallet::signer::TransactionSigner
+
+mod signer;
+pub use signer::*;

crates/hwi/src/signer.rs

@@ -0,0 +1,94 @@
+use bdk::bitcoin::bip32::Fingerprint;
+use bdk::bitcoin::secp256k1::{All, Secp256k1};
+use bdk::bitcoin::Psbt;
+
+use hwi::error::Error;
+use hwi::types::{HWIChain, HWIDevice};
+use hwi::HWIClient;
+
+use bdk::signer::{SignerCommon, SignerError, SignerId, TransactionSigner};
+
+#[derive(Debug)]
+/// Custom signer for Hardware Wallets
+///
+/// This ignores `sign_options` and leaves the decisions up to the hardware wallet.
+pub struct HWISigner {
+    fingerprint: Fingerprint,
+    client: HWIClient,
+}
+
+impl HWISigner {
+    /// Create a instance from the specified device and chain
+    pub fn from_device(device: &HWIDevice, chain: HWIChain) -> Result<HWISigner, Error> {
+        let client = HWIClient::get_client(device, false, chain)?;
+        Ok(HWISigner {
+            fingerprint: device.fingerprint,
+            client,
+        })
+    }
+}
+
+impl SignerCommon for HWISigner {
+    fn id(&self, _secp: &Secp256k1<All>) -> SignerId {
+        SignerId::Fingerprint(self.fingerprint)
+    }
+}
+
+impl TransactionSigner for HWISigner {
+    fn sign_transaction(
+        &self,
+        psbt: &mut Psbt,
+        _sign_options: &bdk::SignOptions,
+        _secp: &Secp256k1<All>,
+    ) -> Result<(), SignerError> {
+        psbt.combine(
+            self.client
+                .sign_tx(psbt)
+                .map_err(|e| {
+                    SignerError::External(format!("While signing with hardware wallet: {}", e))
+                })?
+                .psbt,
+        )
+        .expect("Failed to combine HW signed psbt with passed PSBT");
+        Ok(())
+    }
+}
+
+// TODO: re-enable this once we have the `get_funded_wallet` test util
+// #[cfg(test)]
+// mod tests {
+//     #[test]
+//     fn test_hardware_signer() {
+//         use std::sync::Arc;
+//
+//         use bdk::tests::get_funded_wallet;
+//         use bdk::signer::SignerOrdering;
+//         use bdk::bitcoin::Network;
+//         use crate::HWISigner;
+//         use hwi::HWIClient;
+//
+//         let mut devices = HWIClient::enumerate().unwrap();
+//         if devices.is_empty() {
+//             panic!("No devices found!");
+//         }
+//         let device = devices.remove(0).unwrap();
+//         let client = HWIClient::get_client(&device, true, Network::Regtest.into()).unwrap();
+//         let descriptors = client.get_descriptors::<String>(None).unwrap();
+//         let custom_signer = HWISigner::from_device(&device, Network::Regtest.into()).unwrap();
+//
+//         let (mut wallet, _) = get_funded_wallet(&descriptors.internal[0]);
+//         wallet.add_signer(
+//             bdk::KeychainKind::External,
+//             SignerOrdering(200),
+//             Arc::new(custom_signer),
+//         );
+//
+//         let addr = wallet.get_address(bdk::wallet::AddressIndex::LastUnused);
+//         let mut builder = wallet.build_tx();
+//         builder.drain_to(addr.script_pubkey()).drain_wallet();
+//         let (mut psbt, _) = builder.finish().unwrap();
+//
+//         let finalized = wallet.sign(&mut psbt, Default::default()).unwrap();
+//         assert!(finalized);
+//     }
+// }

crates/persist/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "bdk_persist"
+homepage = "https://bitcoindevkit.org"
+version = "0.2.0"
+repository = "https://github.com/bitcoindevkit/bdk"
+documentation = "https://docs.rs/bdk_persist"
+description = "Types that define data persistence of a BDK wallet"
+keywords = ["bitcoin", "wallet", "persistence", "database"]
+readme = "README.md"
+license = "MIT OR Apache-2.0"
+authors = ["Bitcoin Dev Kit Developers"]
+edition = "2021"
+rust-version = "1.63"
+
+[dependencies]
+anyhow = { version = "1", default-features = false }
+bdk_chain = { path = "../chain", version = "0.14.0", default-features = false }
+
+[features]
+default = ["bdk_chain/std"]
+
+

crates/persist/README.md

@@ -0,0 +1,3 @@
+# BDK Persist
+
+This crate is home to the [`PersistBackend`](crate::PersistBackend) trait which defines the behavior of a database to perform the task of persisting changes made to BDK data structures. The [`Persist`](crate::Persist) type provides a convenient wrapper around a `PersistBackend` that allows staging changes before committing them.

crates/persist/src/lib.rs

@@ -0,0 +1,5 @@
+#![doc = include_str!("../README.md")]
+#![no_std]
+#![warn(missing_docs)]
+mod persist;
+pub use persist::*;

crates/persist/src/persist.rs

@@ -1,26 +1,33 @@
-use core::convert::Infallible;
+extern crate alloc;
+use alloc::boxed::Box;
+use bdk_chain::Append;
+use core::fmt;
 
-use crate::Append;
-
-/// `Persist` wraps a [`PersistBackend`] (`B`) to create a convenient staging area for changes (`C`)
+/// `Persist` wraps a [`PersistBackend`] to create a convenient staging area for changes (`C`)
 /// before they are persisted.
 ///
 /// Not all changes to the in-memory representation needs to be written to disk right away, so
 /// [`Persist::stage`] can be used to *stage* changes first and then [`Persist::commit`] can be used
 /// to write changes to disk.
-#[derive(Debug)]
-pub struct Persist<B, C> {
-    backend: B,
+pub struct Persist<C> {
+    backend: Box<dyn PersistBackend<C> + Send + Sync>,
     stage: C,
 }
 
-impl<B, C> Persist<B, C>
+impl<C: fmt::Debug> fmt::Debug for Persist<C> {
+    fn fmt(&self, fmt: &mut core::fmt::Formatter<'_>) -> Result<(), core::fmt::Error> {
+        write!(fmt, "{:?}", self.stage)?;
+        Ok(())
+    }
+}
+
+impl<C> Persist<C>
 where
-    B: PersistBackend<C>,
     C: Default + Append,
 {
     /// Create a new [`Persist`] from [`PersistBackend`].
-    pub fn new(backend: B) -> Self {
+    pub fn new(backend: impl PersistBackend<C> + Send + Sync + 'static) -> Self {
+        let backend = Box::new(backend);
         Self {
             backend,
             stage: Default::default(),
@@ -46,7 +53,7 @@ where
     /// # Error
     ///
     /// Returns a backend-defined error if this fails.
-    pub fn commit(&mut self) -> Result<Option<C>, B::WriteError> {
+    pub fn commit(&mut self) -> anyhow::Result<Option<C>> {
         if self.stage.is_empty() {
             return Ok(None);
         }
@@ -55,6 +62,18 @@ where
             // if written successfully, take and return `self.stage`
             .map(|_| Some(core::mem::take(&mut self.stage)))
     }
+
+    /// Stages a new changeset and commits it (along with any other previously staged changes) to
+    /// the persistence backend
+    ///
+    /// Convenience method for calling [`stage`] and then [`commit`].
+    ///
+    /// [`stage`]: Self::stage
+    /// [`commit`]: Self::commit
+    pub fn stage_and_commit(&mut self, changeset: C) -> anyhow::Result<Option<C>> {
+        self.stage(changeset);
+        self.commit()
+    }
 }
 
 /// A persistence backend for [`Persist`].
@@ -62,12 +81,6 @@ where
 /// `C` represents the changeset; a datatype that records changes made to in-memory data structures
 /// that are to be persisted, or retrieved from persistence.
 pub trait PersistBackend<C> {
-    /// The error the backend returns when it fails to write.
-    type WriteError: core::fmt::Debug;
-
-    /// The error the backend returns when it fails to load changesets `C`.
-    type LoadError: core::fmt::Debug;
-
     /// Writes a changeset to the persistence backend.
     ///
     /// It is up to the backend what it does with this. It could store every changeset in a list or
@@ -76,22 +89,18 @@ pub trait PersistBackend<C> {
     /// changesets had been applied sequentially.
     ///
     /// [`load_from_persistence`]: Self::load_from_persistence
-    fn write_changes(&mut self, changeset: &C) -> Result<(), Self::WriteError>;
+    fn write_changes(&mut self, changeset: &C) -> anyhow::Result<()>;
 
     /// Return the aggregate changeset `C` from persistence.
-    fn load_from_persistence(&mut self) -> Result<Option<C>, Self::LoadError>;
+    fn load_from_persistence(&mut self) -> anyhow::Result<Option<C>>;
 }
 
 impl<C> PersistBackend<C> for () {
-    type WriteError = Infallible;
-
-    type LoadError = Infallible;
-
-    fn write_changes(&mut self, _changeset: &C) -> Result<(), Self::WriteError> {
+    fn write_changes(&mut self, _changeset: &C) -> anyhow::Result<()> {
         Ok(())
     }
 
-    fn load_from_persistence(&mut self) -> Result<Option<C>, Self::LoadError> {
+    fn load_from_persistence(&mut self) -> anyhow::Result<Option<C>> {
         Ok(None)
     }
 }

crates/testenv/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "bdk_testenv"
+version = "0.4.0"
+edition = "2021"
+rust-version = "1.63"
+homepage = "https://bitcoindevkit.org"
+repository = "https://github.com/bitcoindevkit/bdk"
+documentation = "https://docs.rs/bdk_testenv"
+description = "Testing framework for BDK chain sources."
+license = "MIT OR Apache-2.0"
+readme = "README.md"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bdk_chain = { path = "../chain", version = "0.14", default-features = false }
+electrsd = { version= "0.27.1", features = ["bitcoind_25_0", "esplora_a33e97e1", "legacy"] }
+
+[features]
+default = ["std"]
+std = ["bdk_chain/std"]
+serde = ["bdk_chain/serde"]

crates/testenv/README.md

@@ -0,0 +1,6 @@
+# BDK TestEnv
+
+This crate sets up a regtest environment with a single [`bitcoind`] node
+connected to an [`electrs`] instance. This framework provides the infrastructure
+for testing chain source crates, e.g., [`bdk_chain`], [`bdk_electrum`],
+[`bdk_esplora`], etc.

crates/testenv/src/lib.rs

@@ -0,0 +1,304 @@
+use bdk_chain::{
+    bitcoin::{
+        address::NetworkChecked, block::Header, hash_types::TxMerkleNode, hashes::Hash,
+        secp256k1::rand::random, transaction, Address, Amount, Block, BlockHash, CompactTarget,
+        ScriptBuf, ScriptHash, Transaction, TxIn, TxOut, Txid,
+    },
+    local_chain::CheckPoint,
+    BlockId,
+};
+use bitcoincore_rpc::{
+    bitcoincore_rpc_json::{GetBlockTemplateModes, GetBlockTemplateRules},
+    RpcApi,
+};
+pub use electrsd;
+pub use electrsd::bitcoind;
+pub use electrsd::bitcoind::anyhow;
+pub use electrsd::bitcoind::bitcoincore_rpc;
+pub use electrsd::electrum_client;
+use electrsd::electrum_client::ElectrumApi;
+use std::time::Duration;
+
+/// Struct for running a regtest environment with a single `bitcoind` node with an `electrs`
+/// instance connected to it.
+pub struct TestEnv {
+    pub bitcoind: electrsd::bitcoind::BitcoinD,
+    pub electrsd: electrsd::ElectrsD,
+}
+
+impl TestEnv {
+    /// Construct a new [`TestEnv`] instance with default configurations.
+    pub fn new() -> anyhow::Result<Self> {
+        let bitcoind = match std::env::var_os("BITCOIND_EXE") {
+            Some(bitcoind_path) => electrsd::bitcoind::BitcoinD::new(bitcoind_path),
+            None => {
+                let bitcoind_exe = electrsd::bitcoind::downloaded_exe_path()
+                    .expect(
+                "you need to provide an env var BITCOIND_EXE or specify a bitcoind version feature",
+                );
+                electrsd::bitcoind::BitcoinD::with_conf(
+                    bitcoind_exe,
+                    &electrsd::bitcoind::Conf::default(),
+                )
+            }
+        }?;
+
+        let mut electrsd_conf = electrsd::Conf::default();
+        electrsd_conf.http_enabled = true;
+        let electrsd = match std::env::var_os("ELECTRS_EXE") {
+            Some(env_electrs_exe) => {
+                electrsd::ElectrsD::with_conf(env_electrs_exe, &bitcoind, &electrsd_conf)
+            }
+            None => {
+                let electrs_exe = electrsd::downloaded_exe_path()
+                    .expect("electrs version feature must be enabled");
+                electrsd::ElectrsD::with_conf(electrs_exe, &bitcoind, &electrsd_conf)
+            }
+        }?;
+
+        Ok(Self { bitcoind, electrsd })
+    }
+
+    /// Exposes the [`ElectrumApi`] calls from the Electrum client.
+    pub fn electrum_client(&self) -> &impl ElectrumApi {
+        &self.electrsd.client
+    }
+
+    /// Exposes the [`RpcApi`] calls from [`bitcoincore_rpc`].
+    pub fn rpc_client(&self) -> &impl RpcApi {
+        &self.bitcoind.client
+    }
+
+    // Reset `electrsd` so that new blocks can be seen.
+    pub fn reset_electrsd(mut self) -> anyhow::Result<Self> {
+        let mut electrsd_conf = electrsd::Conf::default();
+        electrsd_conf.http_enabled = true;
+        let electrsd = match std::env::var_os("ELECTRS_EXE") {
+            Some(env_electrs_exe) => {
+                electrsd::ElectrsD::with_conf(env_electrs_exe, &self.bitcoind, &electrsd_conf)
+            }
+            None => {
+                let electrs_exe = electrsd::downloaded_exe_path()
+                    .expect("electrs version feature must be enabled");
+                electrsd::ElectrsD::with_conf(electrs_exe, &self.bitcoind, &electrsd_conf)
+            }
+        }?;
+        self.electrsd = electrsd;
+        Ok(self)
+    }
+
+    /// Mine a number of blocks of a given size `count`, which may be specified to a given coinbase
+    /// `address`.
+    pub fn mine_blocks(
+        &self,
+        count: usize,
+        address: Option<Address>,
+    ) -> anyhow::Result<Vec<BlockHash>> {
+        let coinbase_address = match address {
+            Some(address) => address,
+            None => self
+                .bitcoind
+                .client
+                .get_new_address(None, None)?
+                .assume_checked(),
+        };
+        let block_hashes = self
+            .bitcoind
+            .client
+            .generate_to_address(count as _, &coinbase_address)?;
+        Ok(block_hashes)
+    }
+
+    /// Mine a block that is guaranteed to be empty even with transactions in the mempool.
+    pub fn mine_empty_block(&self) -> anyhow::Result<(usize, BlockHash)> {
+        let bt = self.bitcoind.client.get_block_template(
+            GetBlockTemplateModes::Template,
+            &[GetBlockTemplateRules::SegWit],
+            &[],
+        )?;
+
+        let txdata = vec![Transaction {
+            version: transaction::Version::ONE,
+            lock_time: bdk_chain::bitcoin::absolute::LockTime::from_height(0)?,
+            input: vec![TxIn {
+                previous_output: bdk_chain::bitcoin::OutPoint::default(),
+                script_sig: ScriptBuf::builder()
+                    .push_int(bt.height as _)
+                    // randomn number so that re-mining creates unique block
+                    .push_int(random())
+                    .into_script(),
+                sequence: bdk_chain::bitcoin::Sequence::default(),
+                witness: bdk_chain::bitcoin::Witness::new(),
+            }],
+            output: vec![TxOut {
+                value: Amount::ZERO,
+                script_pubkey: ScriptBuf::new_p2sh(&ScriptHash::all_zeros()),
+            }],
+        }];
+
+        let bits: [u8; 4] = bt
+            .bits
+            .clone()
+            .try_into()
+            .expect("rpc provided us with invalid bits");
+
+        let mut block = Block {
+            header: Header {
+                version: bdk_chain::bitcoin::block::Version::default(),
+                prev_blockhash: bt.previous_block_hash,
+                merkle_root: TxMerkleNode::all_zeros(),
+                time: Ord::max(bt.min_time, std::time::UNIX_EPOCH.elapsed()?.as_secs()) as u32,
+                bits: CompactTarget::from_consensus(u32::from_be_bytes(bits)),
+                nonce: 0,
+            },
+            txdata,
+        };
+
+        block.header.merkle_root = block.compute_merkle_root().expect("must compute");
+
+        for nonce in 0..=u32::MAX {
+            block.header.nonce = nonce;
+            if block.header.target().is_met_by(block.block_hash()) {
+                break;
+            }
+        }
+
+        self.bitcoind.client.submit_block(&block)?;
+        Ok((bt.height as usize, block.block_hash()))
+    }
+
+    /// This method waits for the Electrum notification indicating that a new block has been mined.
+    pub fn wait_until_electrum_sees_block(&self) -> anyhow::Result<()> {
+        self.electrsd.client.block_headers_subscribe()?;
+        let mut delay = Duration::from_millis(64);
+
+        loop {
+            self.electrsd.trigger()?;
+            self.electrsd.client.ping()?;
+            if self.electrsd.client.block_headers_pop()?.is_some() {
+                return Ok(());
+            }
+
+            if delay.as_millis() < 512 {
+                delay = delay.mul_f32(2.0);
+            }
+            std::thread::sleep(delay);
+        }
+    }
+
+    /// Invalidate a number of blocks of a given size `count`.
+    pub fn invalidate_blocks(&self, count: usize) -> anyhow::Result<()> {
+        let mut hash = self.bitcoind.client.get_best_block_hash()?;
+        for _ in 0..count {
+            let prev_hash = self
+                .bitcoind
+                .client
+                .get_block_info(&hash)?
+                .previousblockhash;
+            self.bitcoind.client.invalidate_block(&hash)?;
+            match prev_hash {
+                Some(prev_hash) => hash = prev_hash,
+                None => break,
+            }
+        }
+        Ok(())
+    }
+
+    /// Reorg a number of blocks of a given size `count`.
+    /// Refer to [`TestEnv::mine_empty_block`] for more information.
+    pub fn reorg(&self, count: usize) -> anyhow::Result<Vec<BlockHash>> {
+        let start_height = self.bitcoind.client.get_block_count()?;
+        self.invalidate_blocks(count)?;
+
+        let res = self.mine_blocks(count, None);
+        assert_eq!(
+            self.bitcoind.client.get_block_count()?,
+            start_height,
+            "reorg should not result in height change"
+        );
+        res
+    }
+
+    /// Reorg with a number of empty blocks of a given size `count`.
+    pub fn reorg_empty_blocks(&self, count: usize) -> anyhow::Result<Vec<(usize, BlockHash)>> {
+        let start_height = self.bitcoind.client.get_block_count()?;
+        self.invalidate_blocks(count)?;
+
+        let res = (0..count)
+            .map(|_| self.mine_empty_block())
+            .collect::<Result<Vec<_>, _>>()?;
+        assert_eq!(
+            self.bitcoind.client.get_block_count()?,
+            start_height,
+            "reorg should not result in height change"
+        );
+        Ok(res)
+    }
+
+    /// Send a tx of a given `amount` to a given `address`.
+    pub fn send(&self, address: &Address<NetworkChecked>, amount: Amount) -> anyhow::Result<Txid> {
+        let txid = self
+            .bitcoind
+            .client
+            .send_to_address(address, amount, None, None, None, None, None, None)?;
+        Ok(txid)
+    }
+
+    /// Create a checkpoint linked list of all the blocks in the chain.
+    pub fn make_checkpoint_tip(&self) -> CheckPoint {
+        CheckPoint::from_block_ids((0_u32..).map_while(|height| {
+            self.bitcoind
+                .client
+                .get_block_hash(height as u64)
+                .ok()
+                .map(|hash| BlockId { height, hash })
+        }))
+        .expect("must craft tip")
+    }
+
+    /// Get the genesis hash of the blockchain.
+    pub fn genesis_hash(&self) -> anyhow::Result<BlockHash> {
+        let hash = self.bitcoind.client.get_block_hash(0)?;
+        Ok(hash)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::TestEnv;
+    use electrsd::bitcoind::{anyhow::Result, bitcoincore_rpc::RpcApi};
+
+    /// This checks that reorgs initiated by `bitcoind` is detected by our `electrsd` instance.
+    #[test]
+    fn test_reorg_is_detected_in_electrsd() -> Result<()> {
+        let env = TestEnv::new()?;
+
+        // Mine some blocks.
+        env.mine_blocks(101, None)?;
+        env.wait_until_electrum_sees_block()?;
+        let height = env.bitcoind.client.get_block_count()?;
+        let blocks = (0..=height)
+            .map(|i| env.bitcoind.client.get_block_hash(i))
+            .collect::<Result<Vec<_>, _>>()?;
+
+        // Perform reorg on six blocks.
+        env.reorg(6)?;
+        env.wait_until_electrum_sees_block()?;
+        let reorged_height = env.bitcoind.client.get_block_count()?;
+        let reorged_blocks = (0..=height)
+            .map(|i| env.bitcoind.client.get_block_hash(i))
+            .collect::<Result<Vec<_>, _>>()?;
+
+        assert_eq!(height, reorged_height);
+
+        // Block hashes should not be equal on the six reorged blocks.
+        for (i, (block, reorged_block)) in blocks.iter().zip(reorged_blocks.iter()).enumerate() {
+            match i <= height as usize - 6 {
+                true => assert_eq!(block, reorged_block),
+                false => assert_ne!(block, reorged_block),
+            }
+        }
+
+        Ok(())
+    }
+}

example-crates/example_bitcoind_rpc_polling/README.md

@@ -0,0 +1,68 @@
+# Example RPC CLI
+
+### Simple Regtest Test
+
+1. Start local regtest bitcoind.
+   ```
+    mkdir -p /tmp/regtest/bitcoind
+    bitcoind -regtest -server -fallbackfee=0.0002 -rpcuser=<your-rpc-username> -rpcpassword=<your-rpc-password> -datadir=/tmp/regtest/bitcoind -daemon
+   ```
+2. Create a test bitcoind wallet and set bitcoind env.
+   ```
+   bitcoin-cli -datadir=/tmp/regtest/bitcoind -regtest -rpcuser=<your-rpc-username> -rpcpassword=<your-rpc-password> -named createwallet wallet_name="test"
+   export RPC_URL=127.0.0.1:18443
+   export RPC_USER=<your-rpc-username>
+   export RPC_PASS=<your-rpc-password>
+   ```
+3. Get test bitcoind wallet info.
+   ```
+   bitcoin-cli -rpcwallet="test" -rpcuser=<your-rpc-username> -rpcpassword=<your-rpc-password> -datadir=/tmp/regtest/bitcoind -regtest getwalletinfo
+   ```
+4. Get new test bitcoind wallet address.
+   ```
+   BITCOIND_ADDRESS=$(bitcoin-cli -rpcwallet="test" -datadir=/tmp/regtest/bitcoind -regtest -rpcuser=<your-rpc-username> -rpcpassword=<your-rpc-password> getnewaddress)
+   echo $BITCOIND_ADDRESS
+   ```
+5. Generate 101 blocks with reward to test bitcoind wallet address.
+   ```
+   bitcoin-cli -datadir=/tmp/regtest/bitcoind -regtest -rpcuser=<your-rpc-username> -rpcpassword=<your-rpc-password> generatetoaddress 101 $BITCOIND_ADDRESS
+   ```
+6. Verify test bitcoind wallet balance.
+   ```
+   bitcoin-cli -rpcwallet="test" -datadir=/tmp/regtest/bitcoind -regtest -rpcuser=<your-rpc-username> -rpcpassword=<your-rpc-password> getbalances
+   ```
+7. Set descriptor env and get address from RPC CLI wallet.
+   ```
+   export DESCRIPTOR="wpkh(tprv8ZgxMBicQKsPfK9BTf82oQkHhawtZv19CorqQKPFeaHDMA4dXYX6eWsJGNJ7VTQXWmoHdrfjCYuDijcRmNFwSKcVhswzqs4fugE8turndGc/1/*)"
+   cargo run -- --network regtest address next
+   ```
+8. Send 5 test bitcoin to RPC CLI wallet.
+   ```
+   bitcoin-cli -rpcwallet="test" -datadir=/tmp/regtest/bitcoind -regtest -rpcuser=<your-rpc-username> -rpcpassword=<your-rpc-password> sendtoaddress <address> 5
+   ```
+9. Sync blockchain with RPC CLI wallet.
+   ```
+   cargo run -- --network regtest sync
+   <CNTRL-C to stop syncing>
+   ```
+10. Get RPC CLI wallet unconfirmed balances.
+   ```
+   cargo run -- --network regtest balance
+   ```
+11. Generate 1 block with reward to test bitcoind wallet address.
+   ```
+   bitcoin-cli -datadir=/tmp/regtest/bitcoind -rpcuser=<your-rpc-username> -rpcpassword=<your-rpc-password> -regtest generatetoaddress 10 $BITCOIND_ADDRESS
+   ```
+12. Sync the blockchain with RPC CLI wallet.
+   ```
+   cargo run -- --network regtest sync
+   <CNTRL-C to stop syncing>
+   ```
+13. Get RPC CLI wallet confirmed balances.
+   ```
+   cargo run -- --network regtest balance
+   ```
+14. Get RPC CLI wallet transactions.
+   ```
+   cargo run -- --network regtest txout list
+   ```

example-crates/example_bitcoind_rpc_polling/src/main.rs

@@ -12,9 +12,9 @@ use bdk_bitcoind_rpc::{
     Emitter,
 };
 use bdk_chain::{
-    bitcoin::{Block, Transaction},
+    bitcoin::{constants::genesis_block, Block, Transaction},
     indexed_tx_graph, keychain,
-    local_chain::{self, CheckPoint, LocalChain},
+    local_chain::{self, LocalChain},
     ConfirmationTimeHeightAnchor, IndexedTxGraph,
 };
 use example_cli::{
@@ -42,7 +42,7 @@ type ChangeSet = (
 
 #[derive(Debug)]
 enum Emission {
-    Block { height: u32, block: Block },
+    Block(bdk_bitcoind_rpc::BlockEvent<Block>),
     Mempool(Vec<(Transaction, u64)>),
     Tip(u32),
 }
@@ -64,9 +64,6 @@ struct RpcArgs {
     /// Starting block height to fallback to if no point of agreement if found
     #[clap(env = "FALLBACK_HEIGHT", long, default_value = "0")]
     fallback_height: u32,
-    /// The unused-scripts lookahead will be kept at this size
-    #[clap(long, default_value = "10")]
-    lookahead: u32,
 }
 
 impl From<RpcArgs> for Auth {
@@ -113,17 +110,22 @@ enum RpcCommands {
 
 fn main() -> anyhow::Result<()> {
     let start = Instant::now();
-
-    let (args, keymap, index, db, init_changeset) =
-        example_cli::init::<RpcCommands, RpcArgs, ChangeSet>(DB_MAGIC, DB_PATH)?;
+    let example_cli::Init {
+        args,
+        keymap,
+        index,
+        db,
+        init_changeset,
+    } = example_cli::init::<RpcCommands, RpcArgs, ChangeSet>(DB_MAGIC, DB_PATH)?;
     println!(
         "[{:>10}s] loaded initial changeset from db",
         start.elapsed().as_secs_f32()
     );
+    let (init_chain_changeset, init_graph_changeset) = init_changeset;
 
     let graph = Mutex::new({
         let mut graph = IndexedTxGraph::new(index);
-        graph.apply_changeset(init_changeset.1);
+        graph.apply_changeset(init_graph_changeset);
         graph
     });
     println!(
@@ -131,7 +133,16 @@ fn main() -> anyhow::Result<()> {
         start.elapsed().as_secs_f32()
     );
 
-    let chain = Mutex::new(LocalChain::from_changeset(init_changeset.0)?);
+    let chain = Mutex::new(if init_chain_changeset.is_empty() {
+        let genesis_hash = genesis_block(args.network).block_hash();
+        let (chain, chain_changeset) = LocalChain::from_genesis_hash(genesis_hash);
+        let mut db = db.lock().unwrap();
+        db.stage((chain_changeset, Default::default()));
+        db.commit()?;
+        chain
+    } else {
+        LocalChain::from_changeset(init_chain_changeset)?
+    });
     println!(
         "[{:>10}s] loaded local chain from changeset",
         start.elapsed().as_secs_f32()
@@ -140,7 +151,7 @@ fn main() -> anyhow::Result<()> {
     let rpc_cmd = match args.command {
         example_cli::Commands::ChainSpecific(rpc_cmd) => rpc_cmd,
         general_cmd => {
-            let res = example_cli::handle_commands(
+            return example_cli::handle_commands(
                 &graph,
                 &db,
                 &chain,
@@ -153,21 +164,15 @@ fn main() -> anyhow::Result<()> {
                 },
                 general_cmd,
             );
-            db.lock().unwrap().commit()?;
-            return res;
         }
     };
 
     match rpc_cmd {
         RpcCommands::Sync { rpc_args } => {
             let RpcArgs {
-                fallback_height,
-                lookahead,
-                ..
+                fallback_height, ..
             } = rpc_args;
 
-            graph.lock().unwrap().index.set_lookahead_for_all(lookahead);
-
             let chain_tip = chain.lock().unwrap().tip();
             let rpc_client = rpc_args.new_client()?;
             let mut emitter = Emitter::new(&rpc_client, chain_tip, fallback_height);
@@ -175,17 +180,17 @@ fn main() -> anyhow::Result<()> {
             let mut last_db_commit = Instant::now();
             let mut last_print = Instant::now();
 
-            while let Some((height, block)) = emitter.next_block()? {
+            while let Some(emission) = emitter.next_block()? {
+                let height = emission.block_height();
+
                 let mut chain = chain.lock().unwrap();
                 let mut graph = graph.lock().unwrap();
                 let mut db = db.lock().unwrap();
 
-                let chain_update =
-                    CheckPoint::from_header(&block.header, height).into_update(false);
                 let chain_changeset = chain
-                    .apply_update(chain_update)
+                    .apply_update(emission.checkpoint)
                     .expect("must always apply as we receive blocks in order from emitter");
-                let graph_changeset = graph.apply_block_relevant(block, height);
+                let graph_changeset = graph.apply_block_relevant(&emission.block, height);
                 db.stage((chain_changeset, graph_changeset));
 
                 // commit staged db changes in intervals
@@ -207,7 +212,7 @@ fn main() -> anyhow::Result<()> {
                         graph.graph().balance(
                             &*chain,
                             synced_to.block_id(),
-                            graph.index.outpoints().iter().cloned(),
+                            graph.index.outpoints(),
                             |(k, _), _| k == &Keychain::Internal,
                         )
                     };
@@ -233,13 +238,10 @@ fn main() -> anyhow::Result<()> {
         }
         RpcCommands::Live { rpc_args } => {
             let RpcArgs {
-                fallback_height,
-                lookahead,
-                ..
+                fallback_height, ..
             } = rpc_args;
             let sigterm_flag = start_ctrlc_handler();
 
-            graph.lock().unwrap().index.set_lookahead_for_all(lookahead);
             let last_cp = chain.lock().unwrap().tip();
 
             println!(
@@ -256,7 +258,8 @@ fn main() -> anyhow::Result<()> {
 
                 loop {
                     match emitter.next_block()? {
-                        Some((height, block)) => {
+                        Some(block_emission) => {
+                            let height = block_emission.block_height();
                             if sigterm_flag.load(Ordering::Acquire) {
                                 break;
                             }
@@ -264,7 +267,7 @@ fn main() -> anyhow::Result<()> {
                                 block_count = rpc_client.get_block_count()? as u32;
                                 tx.send(Emission::Tip(block_count))?;
                             }
-                            tx.send(Emission::Block { height, block })?;
+                            tx.send(Emission::Block(block_emission))?;
                         }
                         None => {
                             if await_flag(&sigterm_flag, MEMPOOL_EMIT_DELAY) {
@@ -293,13 +296,13 @@ fn main() -> anyhow::Result<()> {
                 let mut chain = chain.lock().unwrap();
 
                 let changeset = match emission {
-                    Emission::Block { height, block } => {
-                        let chain_update =
-                            CheckPoint::from_header(&block.header, height).into_update(false);
+                    Emission::Block(block_emission) => {
+                        let height = block_emission.block_height();
                         let chain_changeset = chain
-                            .apply_update(chain_update)
+                            .apply_update(block_emission.checkpoint)
                             .expect("must always apply as we receive blocks in order from emitter");
-                        let graph_changeset = graph.apply_block_relevant(block, height);
+                        let graph_changeset =
+                            graph.apply_block_relevant(&block_emission.block, height);
                         (chain_changeset, graph_changeset)
                     }
                     Emission::Mempool(mempool_txs) => {
@@ -333,7 +336,7 @@ fn main() -> anyhow::Result<()> {
                         graph.graph().balance(
                             &*chain,
                             synced_to.block_id(),
-                            graph.index.outpoints().iter().cloned(),
+                            graph.index.outpoints(),
                             |(k, _), _| k == &Keychain::Internal,
                         )
                     };

example-crates/example_cli/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 
 [dependencies]
 bdk_chain = { path = "../../crates/chain", features = ["serde", "miniscript"]}
+bdk_persist = { path = "../../crates/persist" }
 bdk_file_store = { path = "../../crates/file_store" }
 bdk_tmp_plan = { path = "../../nursery/tmp_plan" }
 bdk_coin_select = { path = "../../nursery/coin_select" }

example-crates/example_cli/src/lib.rs

@@ -3,12 +3,14 @@ use anyhow::Context;
 use bdk_coin_select::{coin_select_bnb, CoinSelector, CoinSelectorOpt, WeightedValue};
 use bdk_file_store::Store;
 use serde::{de::DeserializeOwned, Serialize};
-use std::{cmp::Reverse, collections::HashMap, path::PathBuf, sync::Mutex, time::Duration};
+use std::{cmp::Reverse, collections::BTreeMap, path::PathBuf, sync::Mutex, time::Duration};
 
 use bdk_chain::{
     bitcoin::{
-        absolute, address, psbt::Prevouts, secp256k1::Secp256k1, sighash::SighashCache, Address,
-        Network, Sequence, Transaction, TxIn, TxOut,
+        absolute, address,
+        secp256k1::Secp256k1,
+        sighash::{Prevouts, SighashCache},
+        transaction, Address, Amount, Network, Sequence, Transaction, TxIn, TxOut,
     },
     indexed_tx_graph::{self, IndexedTxGraph},
     keychain::{self, KeychainTxOutIndex},
@@ -17,9 +19,10 @@ use bdk_chain::{
         descriptor::{DescriptorSecretKey, KeyMap},
         Descriptor, DescriptorPublicKey,
     },
-    Anchor, Append, ChainOracle, DescriptorExt, FullTxOut, Persist, PersistBackend,
+    Anchor, Append, ChainOracle, DescriptorExt, FullTxOut,
 };
 pub use bdk_file_store;
+use bdk_persist::{Persist, PersistBackend};
 pub use clap;
 
 use clap::{Parser, Subcommand};
@@ -29,7 +32,6 @@ pub type KeychainChangeSet<A> = (
     local_chain::ChangeSet,
     indexed_tx_graph::ChangeSet<A, keychain::ChangeSet<Keychain>>,
 );
-pub type Database<'m, C> = Persist<Store<'m, C>, C>;
 
 #[derive(Parser)]
 #[clap(author, version, about, long_about = None)]
@@ -53,7 +55,6 @@ pub struct Args<CS: clap::Subcommand, S: clap::Args> {
     pub command: Commands<CS, S>,
 }
 
-#[allow(clippy::almost_swapped)]
 #[derive(Subcommand, Debug, Clone)]
 pub enum Commands<CS: clap::Subcommand, S: clap::Args> {
     #[clap(flatten)]
@@ -73,7 +74,9 @@ pub enum Commands<CS: clap::Subcommand, S: clap::Args> {
     },
     /// Send coins to an address.
     Send {
+        /// Amount to send in satoshis
         value: u64,
+        /// Destination address
         address: Address<address::NetworkUnchecked>,
         #[clap(short, default_value = "bnb")]
         coin_select: CoinSelectionAlgo,
@@ -135,7 +138,6 @@ impl core::fmt::Display for CoinSelectionAlgo {
     }
 }
 
-#[allow(clippy::almost_swapped)]
 #[derive(Subcommand, Debug, Clone)]
 pub enum AddressCmd {
     /// Get the next unused address.
@@ -144,14 +146,17 @@ pub enum AddressCmd {
     New,
     /// List all addresses
     List {
+        /// List change addresses
         #[clap(long)]
         change: bool,
     },
+    /// Get last revealed address index for each keychain.
     Index,
 }
 
 #[derive(Subcommand, Debug, Clone)]
 pub enum TxOutCmd {
+    /// List transaction outputs.
     List {
         /// Return only spent outputs.
         #[clap(short, long)]
@@ -185,18 +190,20 @@ impl core::fmt::Display for Keychain {
     }
 }
 
-#[allow(clippy::type_complexity)]
+pub struct CreateTxChange {
+    pub index_changeset: keychain::ChangeSet<Keychain>,
+    pub change_keychain: Keychain,
+    pub index: u32,
+}
+
 pub fn create_tx<A: Anchor, O: ChainOracle>(
     graph: &mut KeychainTxGraph<A>,
     chain: &O,
-    keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
+    keymap: &BTreeMap<DescriptorPublicKey, DescriptorSecretKey>,
     cs_algorithm: CoinSelectionAlgo,
     address: Address,
     value: u64,
-) -> anyhow::Result<(
-    Transaction,
-    Option<(keychain::ChangeSet<Keychain>, (Keychain, u32))>,
-)>
+) -> anyhow::Result<(Transaction, Option<CreateTxChange>)>
 where
     O::Error: std::error::Error + Send + Sync + 'static,
 {
@@ -230,7 +237,7 @@ where
         .iter()
         .map(|(plan, utxo)| {
             WeightedValue::new(
-                utxo.txout.value,
+                utxo.txout.value.to_sat(),
                 plan.expected_weight() as _,
                 plan.witness_version().is_some(),
             )
@@ -238,18 +245,24 @@ where
         .collect();
 
     let mut outputs = vec![TxOut {
-        value,
+        value: Amount::from_sat(value),
         script_pubkey: address.script_pubkey(),
     }];
 
-    let internal_keychain = if graph.index.keychains().get(&Keychain::Internal).is_some() {
+    let internal_keychain = if graph
+        .index
+        .keychains()
+        .any(|(k, _)| *k == Keychain::Internal)
+    {
         Keychain::Internal
     } else {
         Keychain::External
     };
 
-    let ((change_index, change_script), change_changeset) =
-        graph.index.next_unused_spk(&internal_keychain);
+    let ((change_index, change_script), change_changeset) = graph
+        .index
+        .next_unused_spk(&internal_keychain)
+        .expect("Must exist");
     changeset.append(change_changeset);
 
     // Clone to drop the immutable reference.
@@ -259,8 +272,9 @@ where
         &graph
             .index
             .keychains()
-            .get(&internal_keychain)
+            .find(|(k, _)| *k == &internal_keychain)
             .expect("must exist")
+            .1
             .at_derivation_index(change_index)
             .expect("change_index can't be hardened"),
         &assets,
@@ -268,7 +282,7 @@ where
     .expect("failed to obtain change plan");
 
     let mut change_output = TxOut {
-        value: 0,
+        value: Amount::ZERO,
         script_pubkey: change_script,
     };
 
@@ -277,8 +291,9 @@ where
         min_drain_value: graph
             .index
             .keychains()
-            .get(&internal_keychain)
+            .find(|(k, _)| *k == &internal_keychain)
             .expect("must exist")
+            .1
             .dust_value(),
         ..CoinSelectorOpt::fund_outputs(
             &outputs,
@@ -306,13 +321,13 @@ where
     let selected_txos = selection.apply_selection(&candidates).collect::<Vec<_>>();
 
     if let Some(drain_value) = selection_meta.drain_value {
-        change_output.value = drain_value;
+        change_output.value = Amount::from_sat(drain_value);
         // if the selection tells us to use change and the change value is sufficient, we add it as an output
         outputs.push(change_output)
     }
 
     let mut transaction = Transaction {
-        version: 0x02,
+        version: transaction::Version::TWO,
         // because the temporary planning module does not support timelocks, we can use the chain
         // tip as the `lock_time` for anti-fee-sniping purposes
         lock_time: absolute::LockTime::from_height(chain.get_chain_tip()?.height)
@@ -388,7 +403,11 @@ where
     }
 
     let change_info = if selection_meta.drain_value.is_some() {
-        Some((changeset, (internal_keychain, change_index)))
+        Some(CreateTxChange {
+            index_changeset: changeset,
+            change_keychain: internal_keychain,
+            index: change_index,
+        })
     } else {
         None
     };
@@ -396,43 +415,43 @@ where
     Ok((transaction, change_info))
 }
 
-#[allow(clippy::type_complexity)]
+// Alias the elements of `Result` of `planned_utxos`
+pub type PlannedUtxo<K, A> = (bdk_tmp_plan::Plan<K>, FullTxOut<A>);
+
 pub fn planned_utxos<A: Anchor, O: ChainOracle, K: Clone + bdk_tmp_plan::CanDerive>(
     graph: &KeychainTxGraph<A>,
     chain: &O,
     assets: &bdk_tmp_plan::Assets<K>,
-) -> Result<Vec<(bdk_tmp_plan::Plan<K>, FullTxOut<A>)>, O::Error> {
+) -> Result<Vec<PlannedUtxo<K, A>>, O::Error> {
     let chain_tip = chain.get_chain_tip()?;
-    let outpoints = graph.index.outpoints().iter().cloned();
+    let outpoints = graph.index.outpoints();
     graph
         .graph()
         .try_filter_chain_unspents(chain, chain_tip, outpoints)
-        .filter_map(
-            #[allow(clippy::type_complexity)]
-            |r| -> Option<Result<(bdk_tmp_plan::Plan<K>, FullTxOut<A>), _>> {
-                let (k, i, full_txo) = match r {
-                    Err(err) => return Some(Err(err)),
-                    Ok(((k, i), full_txo)) => (k, i, full_txo),
-                };
-                let desc = graph
-                    .index
-                    .keychains()
-                    .get(&k)
-                    .expect("keychain must exist")
-                    .at_derivation_index(i)
-                    .expect("i can't be hardened");
-                let plan = bdk_tmp_plan::plan_satisfaction(&desc, assets)?;
-                Some(Ok((plan, full_txo)))
-            },
-        )
+        .filter_map(|r| -> Option<Result<PlannedUtxo<K, A>, _>> {
+            let (k, i, full_txo) = match r {
+                Err(err) => return Some(Err(err)),
+                Ok(((k, i), full_txo)) => (k, i, full_txo),
+            };
+            let desc = graph
+                .index
+                .keychains()
+                .find(|(keychain, _)| *keychain == &k)
+                .expect("keychain must exist")
+                .1
+                .at_derivation_index(i)
+                .expect("i can't be hardened");
+            let plan = bdk_tmp_plan::plan_satisfaction(&desc, assets)?;
+            Some(Ok((plan, full_txo)))
+        })
         .collect()
 }
 
 pub fn handle_commands<CS: clap::Subcommand, S: clap::Args, A: Anchor, O: ChainOracle, C>(
     graph: &Mutex<KeychainTxGraph<A>>,
-    db: &Mutex<Database<C>>,
+    db: &Mutex<Persist<C>>,
     chain: &Mutex<O>,
-    keymap: &HashMap<DescriptorPublicKey, DescriptorSecretKey>,
+    keymap: &BTreeMap<DescriptorPublicKey, DescriptorSecretKey>,
     network: Network,
     broadcast: impl FnOnce(S, &Transaction) -> anyhow::Result<()>,
     cmd: Commands<CS, S>,
@@ -455,13 +474,13 @@ where
                         _ => unreachable!("only these two variants exist in match arm"),
                     };
 
-                    let ((spk_i, spk), index_changeset) = spk_chooser(index, &Keychain::External);
+                    let ((spk_i, spk), index_changeset) =
+                        spk_chooser(index, &Keychain::External).expect("Must exist");
                     let db = &mut *db.lock().unwrap();
-                    db.stage(C::from((
+                    db.stage_and_commit(C::from((
                         local_chain::ChangeSet::default(),
                         indexed_tx_graph::ChangeSet::from(index_changeset),
-                    )));
-                    db.commit()?;
+                    )))?;
                     let addr =
                         Address::from_script(spk, network).context("failed to derive address")?;
                     println!("[address @ {}] {}", spk_i, addr);
@@ -478,14 +497,14 @@ where
                         true => Keychain::Internal,
                         false => Keychain::External,
                     };
-                    for (spk_i, spk) in index.revealed_spks_of_keychain(&target_keychain) {
+                    for (spk_i, spk) in index.revealed_keychain_spks(&target_keychain) {
                         let address = Address::from_script(spk, network)
                             .expect("should always be able to derive address");
                         println!(
                             "{:?} {} used:{}",
                             spk_i,
                             address,
-                            index.is_used(&(target_keychain, spk_i))
+                            index.is_used(target_keychain, spk_i)
                         );
                     }
                     Ok(())
@@ -497,18 +516,18 @@ where
             let chain = &*chain.lock().unwrap();
             fn print_balances<'a>(
                 title_str: &'a str,
-                items: impl IntoIterator<Item = (&'a str, u64)>,
+                items: impl IntoIterator<Item = (&'a str, Amount)>,
             ) {
                 println!("{}:", title_str);
                 for (name, amount) in items.into_iter() {
-                    println!("    {:<10} {:>12} sats", name, amount)
+                    println!("    {:<10} {:>12} sats", name, amount.to_sat())
                 }
             }
 
             let balance = graph.graph().try_balance(
                 chain,
                 chain.get_chain_tip()?,
-                graph.index.outpoints().iter().cloned(),
+                graph.index.outpoints(),
                 |(k, _), _| k == &Keychain::Internal,
             )?;
 
@@ -538,7 +557,7 @@ where
             let graph = &*graph.lock().unwrap();
             let chain = &*chain.lock().unwrap();
             let chain_tip = chain.get_chain_tip()?;
-            let outpoints = graph.index.outpoints().iter().cloned();
+            let outpoints = graph.index.outpoints();
 
             match txout_cmd {
                 TxOutCmd::List {
@@ -595,23 +614,27 @@ where
                 let (tx, change_info) =
                     create_tx(graph, chain, keymap, coin_select, address, value)?;
 
-                if let Some((index_changeset, (change_keychain, index))) = change_info {
+                if let Some(CreateTxChange {
+                    index_changeset,
+                    change_keychain,
+                    index,
+                }) = change_info
+                {
                     // We must first persist to disk the fact that we've got a new address from the
                     // change keychain so future scans will find the tx we're about to broadcast.
                     // If we're unable to persist this, then we don't want to broadcast.
                     {
                         let db = &mut *db.lock().unwrap();
-                        db.stage(C::from((
+                        db.stage_and_commit(C::from((
                             local_chain::ChangeSet::default(),
                             indexed_tx_graph::ChangeSet::from(index_changeset),
-                        )));
-                        db.commit()?;
+                        )))?;
                     }
 
                     // We don't want other callers/threads to use this address while we're using it
                     // but we also don't want to scan the tx we just created because it's not
                     // technically in the blockchain yet.
-                    graph.index.mark_used(&change_keychain, index);
+                    graph.index.mark_used(change_keychain, index);
                     (tx, Some((change_keychain, index)))
                 } else {
                     (tx, None)
@@ -627,16 +650,16 @@ where
                     // We know the tx is at least unconfirmed now. Note if persisting here fails,
                     // it's not a big deal since we can always find it again form
                     // blockchain.
-                    db.lock().unwrap().stage(C::from((
+                    db.lock().unwrap().stage_and_commit(C::from((
                         local_chain::ChangeSet::default(),
                         keychain_changeset,
-                    )));
+                    )))?;
                     Ok(())
                 }
                 Err(e) => {
                     if let Some((keychain, index)) = change_index {
                         // We failed to broadcast, so allow our change address to be used in the future
-                        graph.lock().unwrap().index.unmark_used(&keychain, index);
+                        graph.lock().unwrap().index.unmark_used(keychain, index);
                     }
                     Err(e)
                 }
@@ -645,19 +668,34 @@ where
     }
 }
 
-#[allow(clippy::type_complexity)]
-pub fn init<'m, CS: clap::Subcommand, S: clap::Args, C>(
-    db_magic: &'m [u8],
+/// The initial state returned by [`init`].
+pub struct Init<CS: clap::Subcommand, S: clap::Args, C> {
+    /// Arguments parsed by the cli.
+    pub args: Args<CS, S>,
+    /// Descriptor keymap.
+    pub keymap: KeyMap,
+    /// Keychain-txout index.
+    pub index: KeychainTxOutIndex<Keychain>,
+    /// Persistence backend.
+    pub db: Mutex<Persist<C>>,
+    /// Initial changeset.
+    pub init_changeset: C,
+}
+
+/// Parses command line arguments and initializes all components, creating
+/// a file store with the given parameters, or loading one if it exists.
+pub fn init<CS: clap::Subcommand, S: clap::Args, C>(
+    db_magic: &[u8],
     db_default_path: &str,
-) -> anyhow::Result<(
-    Args<CS, S>,
-    KeyMap,
-    KeychainTxOutIndex<Keychain>,
-    Mutex<Database<'m, C>>,
-    C,
-)>
+) -> anyhow::Result<Init<CS, S, C>>
 where
-    C: Default + Append + Serialize + DeserializeOwned,
+    C: Default
+        + Append
+        + Serialize
+        + DeserializeOwned
+        + core::marker::Send
+        + core::marker::Sync
+        + 'static,
 {
     if std::env::var("BDK_DB_PATH").is_err() {
         std::env::set_var("BDK_DB_PATH", db_default_path);
@@ -667,9 +705,11 @@ where
 
     let mut index = KeychainTxOutIndex::<Keychain>::default();
 
+    // TODO: descriptors are already stored in the db, so we shouldn't re-insert
+    // them in the index here. However, the keymap is not stored in the database.
     let (descriptor, mut keymap) =
         Descriptor::<DescriptorPublicKey>::parse_descriptor(&secp, &args.descriptor)?;
-    index.add_keychain(Keychain::External, descriptor);
+    let _ = index.insert_descriptor(Keychain::External, descriptor);
 
     if let Some((internal_descriptor, internal_keymap)) = args
         .change_descriptor
@@ -678,10 +718,10 @@ where
         .transpose()?
     {
         keymap.extend(internal_keymap);
-        index.add_keychain(Keychain::Internal, internal_descriptor);
+        let _ = index.insert_descriptor(Keychain::Internal, internal_descriptor);
     }
 
-    let mut db_backend = match Store::<'m, C>::open_or_create_new(db_magic, &args.db_path) {
+    let mut db_backend = match Store::<C>::open_or_create_new(db_magic, &args.db_path) {
         Ok(db_backend) => db_backend,
         // we cannot return `err` directly as it has lifetime `'m`
         Err(err) => return Err(anyhow::anyhow!("failed to init db backend: {:?}", err)),
@@ -689,11 +729,11 @@ where
 
     let init_changeset = db_backend.load_from_persistence()?.unwrap_or_default();
 
-    Ok((
+    Ok(Init {
         args,
         keymap,
         index,
-        Mutex::new(Database::new(db_backend)),
+        db: Mutex::new(Persist::new(db_backend)),
         init_changeset,
-    ))
+    })
 }

example-crates/example_electrum/src/main.rs

@@ -1,19 +1,20 @@
 use std::{
-    collections::BTreeMap,
     io::{self, Write},
     sync::Mutex,
 };
 
 use bdk_chain::{
-    bitcoin::{Address, Network, OutPoint, ScriptBuf, Txid},
+    bitcoin::{constants::genesis_block, Address, Network, Txid},
+    collections::BTreeSet,
     indexed_tx_graph::{self, IndexedTxGraph},
     keychain,
     local_chain::{self, LocalChain},
+    spk_client::{FullScanRequest, SyncRequest},
     Append, ConfirmationHeightAnchor,
 };
 use bdk_electrum::{
     electrum_client::{self, Client, ElectrumApi},
-    ElectrumExt, ElectrumUpdate,
+    ElectrumExt,
 };
 use example_cli::{
     anyhow::{self, Context},
@@ -103,8 +104,15 @@ type ChangeSet = (
 );
 
 fn main() -> anyhow::Result<()> {
-    let (args, keymap, index, db, (disk_local_chain, disk_tx_graph)) =
-        example_cli::init::<ElectrumCommands, ElectrumArgs, ChangeSet>(DB_MAGIC, DB_PATH)?;
+    let example_cli::Init {
+        args,
+        keymap,
+        index,
+        db,
+        init_changeset,
+    } = example_cli::init::<ElectrumCommands, ElectrumArgs, ChangeSet>(DB_MAGIC, DB_PATH)?;
+
+    let (disk_local_chain, disk_tx_graph) = init_changeset;
 
     let graph = Mutex::new({
         let mut graph = IndexedTxGraph::new(index);
@@ -112,12 +120,17 @@ fn main() -> anyhow::Result<()> {
         graph
     });
 
-    let chain = Mutex::new(LocalChain::from_changeset(disk_local_chain)?);
+    let chain = Mutex::new({
+        let genesis_hash = genesis_block(args.network).block_hash();
+        let (mut chain, _) = LocalChain::from_genesis_hash(genesis_hash);
+        chain.apply_changeset(&disk_local_chain)?;
+        chain
+    });
 
     let electrum_cmd = match &args.command {
         example_cli::Commands::ChainSpecific(electrum_cmd) => electrum_cmd,
         general_cmd => {
-            let res = example_cli::handle_commands(
+            return example_cli::handle_commands(
                 &graph,
                 &db,
                 &chain,
@@ -130,57 +143,61 @@ fn main() -> anyhow::Result<()> {
                 },
                 general_cmd.clone(),
             );
-
-            db.lock().unwrap().commit()?;
-            return res;
         }
     };
 
     let client = electrum_cmd.electrum_args().client(args.network)?;
 
-    let response = match electrum_cmd.clone() {
+    let (chain_update, mut graph_update, keychain_update) = match electrum_cmd.clone() {
         ElectrumCommands::Scan {
             stop_gap,
             scan_options,
             ..
         } => {
-            let (keychain_spks, tip) = {
+            let request = {
                 let graph = &*graph.lock().unwrap();
                 let chain = &*chain.lock().unwrap();
 
-                let keychain_spks = graph
-                    .index
-                    .spks_of_all_keychains()
-                    .into_iter()
-                    .map(|(keychain, iter)| {
-                        let mut first = true;
-                        let spk_iter = iter.inspect(move |(i, _)| {
-                            if first {
-                                eprint!("\nscanning {}: ", keychain);
-                                first = false;
+                FullScanRequest::from_chain_tip(chain.tip())
+                    .cache_graph_txs(graph.graph())
+                    .set_spks_for_keychain(
+                        Keychain::External,
+                        graph
+                            .index
+                            .unbounded_spk_iter(&Keychain::External)
+                            .into_iter()
+                            .flatten(),
+                    )
+                    .set_spks_for_keychain(
+                        Keychain::Internal,
+                        graph
+                            .index
+                            .unbounded_spk_iter(&Keychain::Internal)
+                            .into_iter()
+                            .flatten(),
+                    )
+                    .inspect_spks_for_all_keychains({
+                        let mut once = BTreeSet::new();
+                        move |k, spk_i, _| {
+                            if once.insert(k) {
+                                eprint!("\nScanning {}: {} ", k, spk_i);
+                            } else {
+                                eprint!("{} ", spk_i);
                             }
-
-                            eprint!("{} ", i);
-                            let _ = io::stdout().flush();
-                        });
-                        (keychain, spk_iter)
+                            io::stdout().flush().expect("must flush");
+                        }
                     })
-                    .collect::<BTreeMap<_, _>>();
-
-                let tip = chain.tip();
-                (keychain_spks, tip)
             };
 
-            client
-                .scan(
-                    tip,
-                    keychain_spks,
-                    core::iter::empty(),
-                    core::iter::empty(),
-                    stop_gap,
-                    scan_options.batch_size,
-                )
+            let res = client
+                .full_scan::<_>(request, stop_gap, scan_options.batch_size, false)
                 .context("scanning the blockchain")?
+                .with_confirmation_height_anchor();
+            (
+                res.chain_update,
+                res.graph_update,
+                Some(res.last_active_indices),
+            )
         }
         ElectrumCommands::Sync {
             mut unused_spks,
@@ -193,7 +210,6 @@ fn main() -> anyhow::Result<()> {
             // Get a short lock on the tracker to get the spks we're interested in
             let graph = graph.lock().unwrap();
             let chain = chain.lock().unwrap();
-            let chain_tip = chain.tip().block_id();
 
             if !(all_spks || unused_spks || utxos || unconfirmed) {
                 unused_spks = true;
@@ -203,127 +219,130 @@ fn main() -> anyhow::Result<()> {
                 unused_spks = false;
             }
 
-            let mut spks: Box<dyn Iterator<Item = bdk_chain::bitcoin::ScriptBuf>> =
-                Box::new(core::iter::empty());
+            let chain_tip = chain.tip();
+            let mut request =
+                SyncRequest::from_chain_tip(chain_tip.clone()).cache_graph_txs(graph.graph());
+
             if all_spks {
                 let all_spks = graph
                     .index
-                    .all_spks()
-                    .iter()
-                    .map(|(k, v)| (*k, v.clone()))
+                    .revealed_spks(..)
+                    .map(|(k, i, spk)| (k.to_owned(), i, spk.to_owned()))
                     .collect::<Vec<_>>();
-                spks = Box::new(spks.chain(all_spks.into_iter().map(|(index, script)| {
-                    eprintln!("scanning {:?}", index);
-                    script
-                })));
+                request = request.chain_spks(all_spks.into_iter().map(|(k, spk_i, spk)| {
+                    eprint!("Scanning {}: {}", k, spk_i);
+                    spk
+                }));
             }
             if unused_spks {
                 let unused_spks = graph
                     .index
-                    .unused_spks(..)
-                    .map(|(k, v)| (*k, ScriptBuf::from(v)))
+                    .unused_spks()
+                    .map(|(k, i, spk)| (k, i, spk.to_owned()))
                     .collect::<Vec<_>>();
-                spks = Box::new(spks.chain(unused_spks.into_iter().map(|(index, script)| {
-                    eprintln!(
-                        "Checking if address {} {:?} has been used",
-                        Address::from_script(&script, args.network).unwrap(),
-                        index
-                    );
-
-                    script
-                })));
+                request =
+                    request.chain_spks(unused_spks.into_iter().map(move |(k, spk_i, spk)| {
+                        eprint!(
+                            "Checking if address {} {}:{} has been used",
+                            Address::from_script(&spk, args.network).unwrap(),
+                            k,
+                            spk_i,
+                        );
+                        spk
+                    }));
             }
 
-            let mut outpoints: Box<dyn Iterator<Item = OutPoint>> = Box::new(core::iter::empty());
-
             if utxos {
-                let init_outpoints = graph.index.outpoints().iter().cloned();
+                let init_outpoints = graph.index.outpoints();
 
                 let utxos = graph
                     .graph()
-                    .filter_chain_unspents(&*chain, chain_tip, init_outpoints)
+                    .filter_chain_unspents(&*chain, chain_tip.block_id(), init_outpoints)
                     .map(|(_, utxo)| utxo)
                     .collect::<Vec<_>>();
-
-                outpoints = Box::new(
-                    utxos
-                        .into_iter()
-                        .inspect(|utxo| {
-                            eprintln!(
-                                "Checking if outpoint {} (value: {}) has been spent",
-                                utxo.outpoint, utxo.txout.value
-                            );
-                        })
-                        .map(|utxo| utxo.outpoint),
-                );
+                request = request.chain_outpoints(utxos.into_iter().map(|utxo| {
+                    eprint!(
+                        "Checking if outpoint {} (value: {}) has been spent",
+                        utxo.outpoint, utxo.txout.value
+                    );
+                    utxo.outpoint
+                }));
             };
 
-            let mut txids: Box<dyn Iterator<Item = Txid>> = Box::new(core::iter::empty());
-
             if unconfirmed {
                 let unconfirmed_txids = graph
                     .graph()
-                    .list_chain_txs(&*chain, chain_tip)
+                    .list_chain_txs(&*chain, chain_tip.block_id())
                     .filter(|canonical_tx| !canonical_tx.chain_position.is_confirmed())
                     .map(|canonical_tx| canonical_tx.tx_node.txid)
                     .collect::<Vec<Txid>>();
 
-                txids = Box::new(unconfirmed_txids.into_iter().inspect(|txid| {
-                    eprintln!("Checking if {} is confirmed yet", txid);
-                }));
+                request = request.chain_txids(
+                    unconfirmed_txids
+                        .into_iter()
+                        .inspect(|txid| eprint!("Checking if {} is confirmed yet", txid)),
+                );
             }
 
-            let tip = chain.tip();
+            let total_spks = request.spks.len();
+            let total_txids = request.txids.len();
+            let total_ops = request.outpoints.len();
+            request = request
+                .inspect_spks({
+                    let mut visited = 0;
+                    move |_| {
+                        visited += 1;
+                        eprintln!(" [ {:>6.2}% ]", (visited * 100) as f32 / total_spks as f32)
+                    }
+                })
+                .inspect_txids({
+                    let mut visited = 0;
+                    move |_| {
+                        visited += 1;
+                        eprintln!(" [ {:>6.2}% ]", (visited * 100) as f32 / total_txids as f32)
+                    }
+                })
+                .inspect_outpoints({
+                    let mut visited = 0;
+                    move |_| {
+                        visited += 1;
+                        eprintln!(" [ {:>6.2}% ]", (visited * 100) as f32 / total_ops as f32)
+                    }
+                });
+
+            let res = client
+                .sync(request, scan_options.batch_size, false)
+                .context("scanning the blockchain")?
+                .with_confirmation_height_anchor();
 
             // drop lock on graph and chain
             drop((graph, chain));
 
-            let electrum_update = client
-                .scan_without_keychain(tip, spks, txids, outpoints, scan_options.batch_size)
-                .context("scanning the blockchain")?;
-            (electrum_update, BTreeMap::new())
+            (res.chain_update, res.graph_update, None)
         }
     };
 
-    let (
-        ElectrumUpdate {
-            chain_update,
-            relevant_txids,
-        },
-        keychain_update,
-    ) = response;
-
-    let missing_txids = {
-        let graph = &*graph.lock().unwrap();
-        relevant_txids.missing_full_txs(graph.graph())
-    };
-
     let now = std::time::UNIX_EPOCH
         .elapsed()
         .expect("must get time")
         .as_secs();
-
-    let graph_update = relevant_txids.into_tx_graph(&client, Some(now), missing_txids)?;
+    let _ = graph_update.update_last_seen_unconfirmed(now);
 
     let db_changeset = {
         let mut chain = chain.lock().unwrap();
         let mut graph = graph.lock().unwrap();
 
-        let chain = chain.apply_update(chain_update)?;
+        let chain_changeset = chain.apply_update(chain_update)?;
 
-        let indexed_tx_graph = {
-            let mut changeset =
-                indexed_tx_graph::ChangeSet::<ConfirmationHeightAnchor, _>::default();
-            let (_, indexer) = graph.index.reveal_to_target_multi(&keychain_update);
-            changeset.append(indexed_tx_graph::ChangeSet {
-                indexer,
-                ..Default::default()
-            });
-            changeset.append(graph.apply_update(graph_update));
-            changeset
-        };
+        let mut indexed_tx_graph_changeset =
+            indexed_tx_graph::ChangeSet::<ConfirmationHeightAnchor, _>::default();
+        if let Some(keychain_update) = keychain_update {
+            let (_, keychain_changeset) = graph.index.reveal_to_target_multi(&keychain_update);
+            indexed_tx_graph_changeset.append(keychain_changeset.into());
+        }
+        indexed_tx_graph_changeset.append(graph.apply_update(graph_update));
 
-        (chain, indexed_tx_graph)
+        (chain_changeset, indexed_tx_graph_changeset)
     };
 
     let mut db = db.lock().unwrap();

example-crates/example_esplora/src/main.rs

@@ -1,14 +1,15 @@
 use std::{
-    collections::{BTreeMap, BTreeSet},
+    collections::BTreeSet,
     io::{self, Write},
     sync::Mutex,
 };
 
 use bdk_chain::{
-    bitcoin::{constants::genesis_block, Address, Network, OutPoint, ScriptBuf, Txid},
+    bitcoin::{constants::genesis_block, Address, Network, Txid},
     indexed_tx_graph::{self, IndexedTxGraph},
     keychain,
     local_chain::{self, LocalChain},
+    spk_client::{FullScanRequest, SyncRequest},
     Append, ConfirmationTimeHeightAnchor,
 };
 
@@ -60,6 +61,7 @@ enum EsploraCommands {
         esplora_args: EsploraArgs,
     },
 }
+
 impl EsploraCommands {
     fn esplora_args(&self) -> EsploraArgs {
         match self {
@@ -86,7 +88,7 @@ impl EsploraArgs {
             _ => panic!("unsupported network"),
         });
 
-        let client = esplora_client::Builder::new(esplora_url).build_blocking()?;
+        let client = esplora_client::Builder::new(esplora_url).build_blocking();
         Ok(client)
     }
 }
@@ -99,8 +101,13 @@ pub struct ScanOptions {
 }
 
 fn main() -> anyhow::Result<()> {
-    let (args, keymap, index, db, init_changeset) =
-        example_cli::init::<EsploraCommands, EsploraArgs, ChangeSet>(DB_MAGIC, DB_PATH)?;
+    let example_cli::Init {
+        args,
+        keymap,
+        index,
+        db,
+        init_changeset,
+    } = example_cli::init::<EsploraCommands, EsploraArgs, ChangeSet>(DB_MAGIC, DB_PATH)?;
 
     let genesis_hash = genesis_block(args.network).block_hash();
 
@@ -125,7 +132,7 @@ fn main() -> anyhow::Result<()> {
         example_cli::Commands::ChainSpecific(esplora_cmd) => esplora_cmd,
         // These are general commands handled by example_cli. Execute the cmd and return.
         general_cmd => {
-            let res = example_cli::handle_commands(
+            return example_cli::handle_commands(
                 &graph,
                 &db,
                 &chain,
@@ -140,72 +147,70 @@ fn main() -> anyhow::Result<()> {
                 },
                 general_cmd.clone(),
             );
-
-            db.lock().unwrap().commit()?;
-            return res;
         }
     };
 
     let client = esplora_cmd.esplora_args().client(args.network)?;
-    // Prepare the `IndexedTxGraph` update based on whether we are scanning or syncing.
+    // Prepare the `IndexedTxGraph` and `LocalChain` updates based on whether we are scanning or
+    // syncing.
+    //
     // Scanning: We are iterating through spks of all keychains and scanning for transactions for
     //   each spk. We start with the lowest derivation index spk and stop scanning after `stop_gap`
     //   number of consecutive spks have no transaction history. A Scan is done in situations of
     //   wallet restoration. It is a special case. Applications should use "sync" style updates
     //   after an initial scan.
+    //
     // Syncing: We only check for specified spks, utxos and txids to update their confirmation
     //   status or fetch missing transactions.
-    let indexed_tx_graph_changeset = match &esplora_cmd {
+    let (local_chain_changeset, indexed_tx_graph_changeset) = match &esplora_cmd {
         EsploraCommands::Scan {
             stop_gap,
             scan_options,
             ..
         } => {
-            let keychain_spks = graph
-                .lock()
-                .expect("mutex must not be poisoned")
-                .index
-                .spks_of_all_keychains()
-                .into_iter()
-                // This `map` is purely for logging.
-                .map(|(keychain, iter)| {
-                    let mut first = true;
-                    let spk_iter = iter.inspect(move |(i, _)| {
-                        if first {
-                            eprint!("\nscanning {}: ", keychain);
-                            first = false;
+            let request = {
+                let chain_tip = chain.lock().expect("mutex must not be poisoned").tip();
+                let indexed_graph = &*graph.lock().expect("mutex must not be poisoned");
+                FullScanRequest::from_keychain_txout_index(chain_tip, &indexed_graph.index)
+                    .inspect_spks_for_all_keychains({
+                        let mut once = BTreeSet::<Keychain>::new();
+                        move |keychain, spk_i, _| {
+                            if once.insert(keychain) {
+                                eprint!("\nscanning {}: ", keychain);
+                            }
+                            eprint!("{} ", spk_i);
+                            // Flush early to ensure we print at every iteration.
+                            let _ = io::stderr().flush();
                         }
-                        eprint!("{} ", i);
-                        // Flush early to ensure we print at every iteration.
-                        let _ = io::stderr().flush();
-                    });
-                    (keychain, spk_iter)
-                })
-                .collect::<BTreeMap<_, _>>();
+                    })
+            };
 
             // The client scans keychain spks for transaction histories, stopping after `stop_gap`
             // is reached. It returns a `TxGraph` update (`graph_update`) and a structure that
             // represents the last active spk derivation indices of keychains
             // (`keychain_indices_update`).
-            let (graph_update, last_active_indices) = client
-                .scan_txs_with_keychains(
-                    keychain_spks,
-                    core::iter::empty(),
-                    core::iter::empty(),
-                    *stop_gap,
-                    scan_options.parallel_requests,
-                )
+            let mut update = client
+                .full_scan(request, *stop_gap, scan_options.parallel_requests)
                 .context("scanning for transactions")?;
 
+            // We want to keep track of the latest time a transaction was seen unconfirmed.
+            let now = std::time::UNIX_EPOCH.elapsed().unwrap().as_secs();
+            let _ = update.graph_update.update_last_seen_unconfirmed(now);
+
             let mut graph = graph.lock().expect("mutex must not be poisoned");
+            let mut chain = chain.lock().expect("mutex must not be poisoned");
             // Because we did a stop gap based scan we are likely to have some updates to our
             // deriviation indices. Usually before a scan you are on a fresh wallet with no
             // addresses derived so we need to derive up to last active addresses the scan found
             // before adding the transactions.
-            let (_, index_changeset) = graph.index.reveal_to_target_multi(&last_active_indices);
-            let mut indexed_tx_graph_changeset = graph.apply_update(graph_update);
-            indexed_tx_graph_changeset.append(index_changeset.into());
-            indexed_tx_graph_changeset
+            (chain.apply_update(update.chain_update)?, {
+                let (_, index_changeset) = graph
+                    .index
+                    .reveal_to_target_multi(&update.last_active_indices);
+                let mut indexed_tx_graph_changeset = graph.apply_update(update.graph_update);
+                indexed_tx_graph_changeset.append(index_changeset.into());
+                indexed_tx_graph_changeset
+            })
         }
         EsploraCommands::Sync {
             mut unused_spks,
@@ -226,64 +231,63 @@ fn main() -> anyhow::Result<()> {
                 unused_spks = false;
             }
 
+            let local_tip = chain.lock().expect("mutex must not be poisoned").tip();
             // Spks, outpoints and txids we want updates on will be accumulated here.
-            let mut spks: Box<dyn Iterator<Item = ScriptBuf>> = Box::new(core::iter::empty());
-            let mut outpoints: Box<dyn Iterator<Item = OutPoint>> = Box::new(core::iter::empty());
-            let mut txids: Box<dyn Iterator<Item = Txid>> = Box::new(core::iter::empty());
+            let mut request = SyncRequest::from_chain_tip(local_tip.clone());
 
             // Get a short lock on the structures to get spks, utxos, and txs that we are interested
             // in.
             {
                 let graph = graph.lock().unwrap();
                 let chain = chain.lock().unwrap();
-                let chain_tip = chain.tip().block_id();
 
                 if *all_spks {
                     let all_spks = graph
                         .index
-                        .all_spks()
-                        .iter()
-                        .map(|(k, v)| (*k, v.clone()))
+                        .revealed_spks(..)
+                        .map(|(k, i, spk)| (k.to_owned(), i, spk.to_owned()))
                         .collect::<Vec<_>>();
-                    spks = Box::new(spks.chain(all_spks.into_iter().map(|(index, script)| {
-                        eprintln!("scanning {:?}", index);
+                    request = request.chain_spks(all_spks.into_iter().map(|(k, i, spk)| {
+                        eprint!("scanning {}:{}", k, i);
                         // Flush early to ensure we print at every iteration.
                         let _ = io::stderr().flush();
-                        script
-                    })));
+                        spk
+                    }));
                 }
                 if unused_spks {
                     let unused_spks = graph
                         .index
-                        .unused_spks(..)
-                        .map(|(k, v)| (*k, v.to_owned()))
+                        .unused_spks()
+                        .map(|(k, i, spk)| (k, i, spk.to_owned()))
                         .collect::<Vec<_>>();
-                    spks = Box::new(spks.chain(unused_spks.into_iter().map(|(index, script)| {
-                        eprintln!(
-                            "Checking if address {} {:?} has been used",
-                            Address::from_script(&script, args.network).unwrap(),
-                            index
-                        );
-                        // Flush early to ensure we print at every iteration.
-                        let _ = io::stderr().flush();
-                        script
-                    })));
+                    request =
+                        request.chain_spks(unused_spks.into_iter().map(move |(k, i, spk)| {
+                            eprint!(
+                                "Checking if address {} {}:{} has been used",
+                                Address::from_script(&spk, args.network).unwrap(),
+                                k,
+                                i,
+                            );
+                            // Flush early to ensure we print at every iteration.
+                            let _ = io::stderr().flush();
+                            spk
+                        }));
                 }
                 if utxos {
                     // We want to search for whether the UTXO is spent, and spent by which
                     // transaction. We provide the outpoint of the UTXO to
                     // `EsploraExt::update_tx_graph_without_keychain`.
-                    let init_outpoints = graph.index.outpoints().iter().cloned();
+                    let init_outpoints = graph.index.outpoints();
                     let utxos = graph
                         .graph()
-                        .filter_chain_unspents(&*chain, chain_tip, init_outpoints)
+                        .filter_chain_unspents(&*chain, local_tip.block_id(), init_outpoints)
                         .map(|(_, utxo)| utxo)
                         .collect::<Vec<_>>();
-                    outpoints = Box::new(
+                    request = request.chain_outpoints(
                         utxos
                             .into_iter()
                             .inspect(|utxo| {
-                                eprintln!(
+                                eprint!(
                                     "Checking if outpoint {} (value: {}) has been spent",
                                     utxo.outpoint, utxo.txout.value
                                 );
@@ -299,56 +303,61 @@ fn main() -> anyhow::Result<()> {
                     // `EsploraExt::update_tx_graph_without_keychain`.
                     let unconfirmed_txids = graph
                         .graph()
-                        .list_chain_txs(&*chain, chain_tip)
+                        .list_chain_txs(&*chain, local_tip.block_id())
                         .filter(|canonical_tx| !canonical_tx.chain_position.is_confirmed())
                         .map(|canonical_tx| canonical_tx.tx_node.txid)
                         .collect::<Vec<Txid>>();
-                    txids = Box::new(unconfirmed_txids.into_iter().inspect(|txid| {
-                        eprintln!("Checking if {} is confirmed yet", txid);
+                    request = request.chain_txids(unconfirmed_txids.into_iter().inspect(|txid| {
+                        eprint!("Checking if {} is confirmed yet", txid);
                         // Flush early to ensure we print at every iteration.
                         let _ = io::stderr().flush();
                     }));
                 }
             }
 
-            let graph_update =
-                client.scan_txs(spks, txids, outpoints, scan_options.parallel_requests)?;
+            let total_spks = request.spks.len();
+            let total_txids = request.txids.len();
+            let total_ops = request.outpoints.len();
+            request = request
+                .inspect_spks({
+                    let mut visited = 0;
+                    move |_| {
+                        visited += 1;
+                        eprintln!(" [ {:>6.2}% ]", (visited * 100) as f32 / total_spks as f32)
+                    }
+                })
+                .inspect_txids({
+                    let mut visited = 0;
+                    move |_| {
+                        visited += 1;
+                        eprintln!(" [ {:>6.2}% ]", (visited * 100) as f32 / total_txids as f32)
+                    }
+                })
+                .inspect_outpoints({
+                    let mut visited = 0;
+                    move |_| {
+                        visited += 1;
+                        eprintln!(" [ {:>6.2}% ]", (visited * 100) as f32 / total_ops as f32)
+                    }
+                });
+            let mut update = client.sync(request, scan_options.parallel_requests)?;
 
-            graph.lock().unwrap().apply_update(graph_update)
+            // Update last seen unconfirmed
+            let now = std::time::UNIX_EPOCH.elapsed().unwrap().as_secs();
+            let _ = update.graph_update.update_last_seen_unconfirmed(now);
+
+            (
+                chain.lock().unwrap().apply_update(update.chain_update)?,
+                graph.lock().unwrap().apply_update(update.graph_update),
+            )
         }
     };
 
     println!();
 
-    // Now that we're done updating the `IndexedTxGraph`, it's time to update the `LocalChain`! We
-    // want the `LocalChain` to have data about all the anchors in the `TxGraph` - for this reason,
-    // we want retrieve the blocks at the heights of the newly added anchors that are missing from
-    // our view of the chain.
-    let (missing_block_heights, tip) = {
-        let chain = &*chain.lock().unwrap();
-        let missing_block_heights = indexed_tx_graph_changeset
-            .graph
-            .missing_heights_from(chain)
-            .collect::<BTreeSet<_>>();
-        let tip = chain.tip();
-        (missing_block_heights, tip)
-    };
-
-    println!("prev tip: {}", tip.height());
-    println!("missing block heights: {:?}", missing_block_heights);
-
-    // Here, we actually fetch the missing blocks and create a `local_chain::Update`.
-    let chain_changeset = {
-        let chain_update = client
-            .update_local_chain(tip, missing_block_heights)
-            .context("scanning for blocks")?;
-        println!("new tip: {}", chain_update.tip.height());
-        chain.lock().unwrap().apply_update(chain_update)?
-    };
-
     // We persist the changes
     let mut db = db.lock().unwrap();
-    db.stage((chain_changeset, indexed_tx_graph_changeset));
+    db.stage((local_chain_changeset, indexed_tx_graph_changeset));
     db.commit()?;
     Ok(())
 }

example-crates/wallet_electrum/src/main.rs

@@ -1,18 +1,18 @@
 const DB_MAGIC: &str = "bdk_wallet_electrum_example";
-const SEND_AMOUNT: u64 = 5000;
+const SEND_AMOUNT: Amount = Amount::from_sat(5000);
 const STOP_GAP: usize = 50;
 const BATCH_SIZE: usize = 5;
 
 use std::io::Write;
 use std::str::FromStr;
 
-use bdk::bitcoin::Address;
-use bdk::wallet::Update;
-use bdk::SignOptions;
+use bdk::bitcoin::{Address, Amount};
+use bdk::chain::collections::HashSet;
 use bdk::{bitcoin::Network, Wallet};
+use bdk::{KeychainKind, SignOptions};
 use bdk_electrum::{
     electrum_client::{self, ElectrumApi},
-    ElectrumExt, ElectrumUpdate,
+    ElectrumExt,
 };
 use bdk_file_store::Store;
 
@@ -29,7 +29,7 @@ fn main() -> Result<(), anyhow::Error> {
         Network::Testnet,
     )?;
 
-    let address = wallet.try_get_address(bdk::wallet::AddressIndex::New)?;
+    let address = wallet.next_unused_address(KeychainKind::External)?;
     println!("Generated Address: {}", address);
 
     let balance = wallet.get_balance();
@@ -38,42 +38,30 @@ fn main() -> Result<(), anyhow::Error> {
     print!("Syncing...");
     let client = electrum_client::Client::new("ssl://electrum.blockstream.info:60002")?;
 
-    let prev_tip = wallet.latest_checkpoint();
-    let keychain_spks = wallet
-        .spks_of_all_keychains()
-        .into_iter()
-        .map(|(k, k_spks)| {
-            let mut once = Some(());
-            let mut stdout = std::io::stdout();
-            let k_spks = k_spks
-                .inspect(move |(spk_i, _)| match once.take() {
-                    Some(_) => print!("\nScanning keychain [{:?}]", k),
-                    None => print!(" {:<3}", spk_i),
-                })
-                .inspect(move |_| stdout.flush().expect("must flush"));
-            (k, k_spks)
+    let request = wallet
+        .start_full_scan()
+        .inspect_spks_for_all_keychains({
+            let mut once = HashSet::<KeychainKind>::new();
+            move |k, spk_i, _| {
+                if once.insert(k) {
+                    print!("\nScanning keychain [{:?}]", k)
+                } else {
+                    print!(" {:<3}", spk_i)
+                }
+            }
         })
-        .collect();
+        .inspect_spks_for_all_keychains(|_, _, _| std::io::stdout().flush().expect("must flush"));
 
-    let (
-        ElectrumUpdate {
-            chain_update,
-            relevant_txids,
-        },
-        keychain_update,
-    ) = client.scan(prev_tip, keychain_spks, None, None, STOP_GAP, BATCH_SIZE)?;
+    let mut update = client
+        .full_scan(request, STOP_GAP, BATCH_SIZE, false)?
+        .with_confirmation_time_height_anchor(&client)?;
+
+    let now = std::time::UNIX_EPOCH.elapsed().unwrap().as_secs();
+    let _ = update.graph_update.update_last_seen_unconfirmed(now);
 
     println!();
 
-    let missing = relevant_txids.missing_full_txs(wallet.as_ref());
-    let graph_update = relevant_txids.into_confirmation_time_tx_graph(&client, None, missing)?;
-
-    let wallet_update = Update {
-        last_active_indices: keychain_update,
-        graph: graph_update,
-        chain: Some(chain_update),
-    };
-    wallet.apply_update(wallet_update)?;
+    wallet.apply_update(update)?;
     wallet.commit()?;
 
     let balance = wallet.get_balance();
@@ -99,7 +87,7 @@ fn main() -> Result<(), anyhow::Error> {
     let finalized = wallet.sign(&mut psbt, SignOptions::default())?;
     assert!(finalized);
 
-    let tx = psbt.extract_tx();
+    let tx = psbt.extract_tx()?;
     client.transaction_broadcast(&tx)?;
     println!("Tx broadcasted! Txid: {}", tx.txid());
 

example-crates/wallet_esplora_async/src/main.rs

@@ -1,15 +1,14 @@
-use std::{io::Write, str::FromStr};
+use std::{collections::BTreeSet, io::Write, str::FromStr};
 
 use bdk::{
-    bitcoin::{Address, Network},
-    wallet::{AddressIndex, Update},
-    SignOptions, Wallet,
+    bitcoin::{Address, Amount, Network, Script},
+    KeychainKind, SignOptions, Wallet,
 };
 use bdk_esplora::{esplora_client, EsploraAsyncExt};
 use bdk_file_store::Store;
 
 const DB_MAGIC: &str = "bdk_wallet_esplora_async_example";
-const SEND_AMOUNT: u64 = 5000;
+const SEND_AMOUNT: Amount = Amount::from_sat(5000);
 const STOP_GAP: usize = 50;
 const PARALLEL_REQUESTS: usize = 5;
 
@@ -27,7 +26,7 @@ async fn main() -> Result<(), anyhow::Error> {
         Network::Testnet,
     )?;
 
-    let address = wallet.try_get_address(AddressIndex::New)?;
+    let address = wallet.next_unused_address(KeychainKind::External)?;
     println!("Generated Address: {}", address);
 
     let balance = wallet.get_balance();
@@ -37,32 +36,44 @@ async fn main() -> Result<(), anyhow::Error> {
     let client =
         esplora_client::Builder::new("https://blockstream.info/testnet/api").build_async()?;
 
-    let prev_tip = wallet.latest_checkpoint();
-    let keychain_spks = wallet
-        .spks_of_all_keychains()
-        .into_iter()
-        .map(|(k, k_spks)| {
-            let mut once = Some(());
-            let mut stdout = std::io::stdout();
-            let k_spks = k_spks
-                .inspect(move |(spk_i, _)| match once.take() {
-                    Some(_) => print!("\nScanning keychain [{:?}]", k),
-                    None => print!(" {:<3}", spk_i),
-                })
-                .inspect(move |_| stdout.flush().expect("must flush"));
-            (k, k_spks)
+    fn generate_inspect(kind: KeychainKind) -> impl FnMut(u32, &Script) + Send + Sync + 'static {
+        let mut once = Some(());
+        let mut stdout = std::io::stdout();
+        move |spk_i, _| {
+            match once.take() {
+                Some(_) => print!("\nScanning keychain [{:?}]", kind),
+                None => print!(" {:<3}", spk_i),
+            };
+            stdout.flush().expect("must flush");
+        }
+    }
+    let request = wallet
+        .start_full_scan()
+        .inspect_spks_for_all_keychains({
+            let mut once = BTreeSet::<KeychainKind>::new();
+            move |keychain, spk_i, _| {
+                match once.insert(keychain) {
+                    true => print!("\nScanning keychain [{:?}]", keychain),
+                    false => print!(" {:<3}", spk_i),
+                }
+                std::io::stdout().flush().expect("must flush")
+            }
         })
-        .collect();
-    let (update_graph, last_active_indices) = client
-        .scan_txs_with_keychains(keychain_spks, None, None, STOP_GAP, PARALLEL_REQUESTS)
+        .inspect_spks_for_keychain(
+            KeychainKind::External,
+            generate_inspect(KeychainKind::External),
+        )
+        .inspect_spks_for_keychain(
+            KeychainKind::Internal,
+            generate_inspect(KeychainKind::Internal),
+        );
+
+    let mut update = client
+        .full_scan(request, STOP_GAP, PARALLEL_REQUESTS)
         .await?;
-    let missing_heights = update_graph.missing_heights(wallet.local_chain());
-    let chain_update = client.update_local_chain(prev_tip, missing_heights).await?;
-    let update = Update {
-        last_active_indices,
-        graph: update_graph,
-        chain: Some(chain_update),
-    };
+    let now = std::time::UNIX_EPOCH.elapsed().unwrap().as_secs();
+    let _ = update.graph_update.update_last_seen_unconfirmed(now);
+
     wallet.apply_update(update)?;
     wallet.commit()?;
     println!();
@@ -90,7 +101,7 @@ async fn main() -> Result<(), anyhow::Error> {
     let finalized = wallet.sign(&mut psbt, SignOptions::default())?;
     assert!(finalized);
 
-    let tx = psbt.extract_tx();
+    let tx = psbt.extract_tx()?;
     client.broadcast(&tx).await?;
     println!("Tx broadcasted! Txid: {}", tx.txid());
 

example-crates/wallet_esplora_blocking/src/main.rs

@@ -1,14 +1,13 @@
 const DB_MAGIC: &str = "bdk_wallet_esplora_example";
-const SEND_AMOUNT: u64 = 1000;
+const SEND_AMOUNT: Amount = Amount::from_sat(1000);
 const STOP_GAP: usize = 5;
 const PARALLEL_REQUESTS: usize = 1;
 
-use std::{io::Write, str::FromStr};
+use std::{collections::BTreeSet, io::Write, str::FromStr};
 
 use bdk::{
-    bitcoin::{Address, Network},
-    wallet::{AddressIndex, Update},
-    SignOptions, Wallet,
+    bitcoin::{Address, Amount, Network},
+    KeychainKind, SignOptions, Wallet,
 };
 use bdk_esplora::{esplora_client, EsploraExt};
 use bdk_file_store::Store;
@@ -26,7 +25,7 @@ fn main() -> Result<(), anyhow::Error> {
         Network::Testnet,
     )?;
 
-    let address = wallet.try_get_address(AddressIndex::New)?;
+    let address = wallet.next_unused_address(KeychainKind::External)?;
     println!("Generated Address: {}", address);
 
     let balance = wallet.get_balance();
@@ -34,34 +33,22 @@ fn main() -> Result<(), anyhow::Error> {
 
     print!("Syncing...");
     let client =
-        esplora_client::Builder::new("https://blockstream.info/testnet/api").build_blocking()?;
+        esplora_client::Builder::new("https://blockstream.info/testnet/api").build_blocking();
 
-    let prev_tip = wallet.latest_checkpoint();
-    let keychain_spks = wallet
-        .spks_of_all_keychains()
-        .into_iter()
-        .map(|(k, k_spks)| {
-            let mut once = Some(());
-            let mut stdout = std::io::stdout();
-            let k_spks = k_spks
-                .inspect(move |(spk_i, _)| match once.take() {
-                    Some(_) => print!("\nScanning keychain [{:?}]", k),
-                    None => print!(" {:<3}", spk_i),
-                })
-                .inspect(move |_| stdout.flush().expect("must flush"));
-            (k, k_spks)
-        })
-        .collect();
+    let request = wallet.start_full_scan().inspect_spks_for_all_keychains({
+        let mut once = BTreeSet::<KeychainKind>::new();
+        move |keychain, spk_i, _| {
+            match once.insert(keychain) {
+                true => print!("\nScanning keychain [{:?}]", keychain),
+                false => print!(" {:<3}", spk_i),
+            };
+            std::io::stdout().flush().expect("must flush")
+        }
+    });
 
-    let (update_graph, last_active_indices) =
-        client.scan_txs_with_keychains(keychain_spks, None, None, STOP_GAP, PARALLEL_REQUESTS)?;
-    let missing_heights = update_graph.missing_heights(wallet.local_chain());
-    let chain_update = client.update_local_chain(prev_tip, missing_heights)?;
-    let update = Update {
-        last_active_indices,
-        graph: update_graph,
-        chain: Some(chain_update),
-    };
+    let mut update = client.full_scan(request, STOP_GAP, PARALLEL_REQUESTS)?;
+    let now = std::time::UNIX_EPOCH.elapsed().unwrap().as_secs();
+    let _ = update.graph_update.update_last_seen_unconfirmed(now);
 
     wallet.apply_update(update)?;
     wallet.commit()?;
@@ -90,7 +77,7 @@ fn main() -> Result<(), anyhow::Error> {
     let finalized = wallet.sign(&mut psbt, SignOptions::default())?;
     assert!(finalized);
 
-    let tx = psbt.extract_tx();
+    let tx = psbt.extract_tx()?;
     client.broadcast(&tx)?;
     println!("Tx broadcasted! Txid: {}", tx.txid());
 

example-crates/wallet_rpc/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "wallet_rpc"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bdk = { path = "../../crates/bdk" }
+bdk_file_store = { path = "../../crates/file_store" }
+bdk_bitcoind_rpc = { path = "../../crates/bitcoind_rpc" }
+
+anyhow = "1"
+clap = { version = "3.2.25", features = ["derive", "env"] }
+ctrlc = "2.0.1"

example-crates/wallet_rpc/README.md

@@ -0,0 +1,45 @@
+# Wallet RPC Example 
+
+```
+$ cargo run --bin wallet_rpc -- --help
+
+wallet_rpc 0.1.0
+Bitcoind RPC example using `bdk::Wallet`
+
+USAGE:
+    wallet_rpc [OPTIONS] <DESCRIPTOR> [CHANGE_DESCRIPTOR]
+
+ARGS:
+    <DESCRIPTOR>           Wallet descriptor [env: DESCRIPTOR=]
+    <CHANGE_DESCRIPTOR>    Wallet change descriptor [env: CHANGE_DESCRIPTOR=]
+
+OPTIONS:
+        --db-path <DB_PATH>
+            Where to store wallet data [env: BDK_DB_PATH=] [default: .bdk_wallet_rpc_example.db]
+
+    -h, --help
+            Print help information
+
+        --network <NETWORK>
+            Bitcoin network to connect to [env: BITCOIN_NETWORK=] [default: testnet]
+
+        --rpc-cookie <RPC_COOKIE>
+            RPC auth cookie file [env: RPC_COOKIE=]
+
+        --rpc-pass <RPC_PASS>
+            RPC auth password [env: RPC_PASS=]
+
+        --rpc-user <RPC_USER>
+            RPC auth username [env: RPC_USER=]
+
+        --start-height <START_HEIGHT>
+            Earliest block height to start sync from [env: START_HEIGHT=] [default: 481824]
+
+        --url <URL>
+            RPC URL [env: RPC_URL=] [default: 127.0.0.1:8332]
+
+    -V, --version
+            Print version information
+
+```
+

example-crates/wallet_rpc/src/main.rs

@@ -0,0 +1,182 @@
+use bdk::{
+    bitcoin::{Block, Network, Transaction},
+    wallet::Wallet,
+};
+use bdk_bitcoind_rpc::{
+    bitcoincore_rpc::{Auth, Client, RpcApi},
+    Emitter,
+};
+use bdk_file_store::Store;
+use clap::{self, Parser};
+use std::{path::PathBuf, sync::mpsc::sync_channel, thread::spawn, time::Instant};
+
+const DB_MAGIC: &str = "bdk-rpc-wallet-example";
+
+/// Bitcoind RPC example using `bdk::Wallet`.
+///
+/// This syncs the chain block-by-block and prints the current balance, transaction count and UTXO
+/// count.
+#[derive(Parser, Debug)]
+#[clap(author, version, about, long_about = None)]
+#[clap(propagate_version = true)]
+pub struct Args {
+    /// Wallet descriptor
+    #[clap(env = "DESCRIPTOR")]
+    pub descriptor: String,
+    /// Wallet change descriptor
+    #[clap(env = "CHANGE_DESCRIPTOR")]
+    pub change_descriptor: Option<String>,
+    /// Earliest block height to start sync from
+    #[clap(env = "START_HEIGHT", long, default_value = "481824")]
+    pub start_height: u32,
+    /// Bitcoin network to connect to
+    #[clap(env = "BITCOIN_NETWORK", long, default_value = "testnet")]
+    pub network: Network,
+    /// Where to store wallet data
+    #[clap(
+        env = "BDK_DB_PATH",
+        long,
+        default_value = ".bdk_wallet_rpc_example.db"
+    )]
+    pub db_path: PathBuf,
+
+    /// RPC URL
+    #[clap(env = "RPC_URL", long, default_value = "127.0.0.1:8332")]
+    pub url: String,
+    /// RPC auth cookie file
+    #[clap(env = "RPC_COOKIE", long)]
+    pub rpc_cookie: Option<PathBuf>,
+    /// RPC auth username
+    #[clap(env = "RPC_USER", long)]
+    pub rpc_user: Option<String>,
+    /// RPC auth password
+    #[clap(env = "RPC_PASS", long)]
+    pub rpc_pass: Option<String>,
+}
+
+impl Args {
+    fn client(&self) -> anyhow::Result<Client> {
+        Ok(Client::new(
+            &self.url,
+            match (&self.rpc_cookie, &self.rpc_user, &self.rpc_pass) {
+                (None, None, None) => Auth::None,
+                (Some(path), _, _) => Auth::CookieFile(path.clone()),
+                (_, Some(user), Some(pass)) => Auth::UserPass(user.clone(), pass.clone()),
+                (_, Some(_), None) => panic!("rpc auth: missing rpc_pass"),
+                (_, None, Some(_)) => panic!("rpc auth: missing rpc_user"),
+            },
+        )?)
+    }
+}
+
+#[derive(Debug)]
+enum Emission {
+    SigTerm,
+    Block(bdk_bitcoind_rpc::BlockEvent<Block>),
+    Mempool(Vec<(Transaction, u64)>),
+}
+
+fn main() -> anyhow::Result<()> {
+    let args = Args::parse();
+
+    let rpc_client = args.client()?;
+    println!(
+        "Connected to Bitcoin Core RPC at {:?}",
+        rpc_client.get_blockchain_info().unwrap()
+    );
+
+    let start_load_wallet = Instant::now();
+    let mut wallet = Wallet::new_or_load(
+        &args.descriptor,
+        args.change_descriptor.as_ref(),
+        Store::<bdk::wallet::ChangeSet>::open_or_create_new(DB_MAGIC.as_bytes(), args.db_path)?,
+        args.network,
+    )?;
+    println!(
+        "Loaded wallet in {}s",
+        start_load_wallet.elapsed().as_secs_f32()
+    );
+
+    let balance = wallet.get_balance();
+    println!("Wallet balance before syncing: {} sats", balance.total());
+
+    let wallet_tip = wallet.latest_checkpoint();
+    println!(
+        "Wallet tip: {} at height {}",
+        wallet_tip.hash(),
+        wallet_tip.height()
+    );
+
+    let (sender, receiver) = sync_channel::<Emission>(21);
+
+    let signal_sender = sender.clone();
+    ctrlc::set_handler(move || {
+        signal_sender
+            .send(Emission::SigTerm)
+            .expect("failed to send sigterm")
+    });
+
+    let emitter_tip = wallet_tip.clone();
+    spawn(move || -> Result<(), anyhow::Error> {
+        let mut emitter = Emitter::new(&rpc_client, emitter_tip, args.start_height);
+        while let Some(emission) = emitter.next_block()? {
+            sender.send(Emission::Block(emission))?;
+        }
+        sender.send(Emission::Mempool(emitter.mempool()?))?;
+        Ok(())
+    });
+
+    let mut blocks_received = 0_usize;
+    for emission in receiver {
+        match emission {
+            Emission::SigTerm => {
+                println!("Sigterm received, exiting...");
+                break;
+            }
+            Emission::Block(block_emission) => {
+                blocks_received += 1;
+                let height = block_emission.block_height();
+                let hash = block_emission.block_hash();
+                let connected_to = block_emission.connected_to();
+                let start_apply_block = Instant::now();
+                wallet.apply_block_connected_to(&block_emission.block, height, connected_to)?;
+                wallet.commit()?;
+                let elapsed = start_apply_block.elapsed().as_secs_f32();
+                println!(
+                    "Applied block {} at height {} in {}s",
+                    hash, height, elapsed
+                );
+            }
+            Emission::Mempool(mempool_emission) => {
+                let start_apply_mempool = Instant::now();
+                wallet.apply_unconfirmed_txs(mempool_emission.iter().map(|(tx, time)| (tx, *time)));
+                wallet.commit()?;
+                println!(
+                    "Applied unconfirmed transactions in {}s",
+                    start_apply_mempool.elapsed().as_secs_f32()
+                );
+                break;
+            }
+        }
+    }
+    let wallet_tip_end = wallet.latest_checkpoint();
+    let balance = wallet.get_balance();
+    println!(
+        "Synced {} blocks in {}s",
+        blocks_received,
+        start_load_wallet.elapsed().as_secs_f32(),
+    );
+    println!(
+        "Wallet tip is '{}:{}'",
+        wallet_tip_end.height(),
+        wallet_tip_end.hash()
+    );
+    println!("Wallet balance is {} sats", balance.total());
+    println!(
+        "Wallet has {} transactions and {} utxos",
+        wallet.transactions().count(),
+        wallet.list_unspent().count()
+    );
+
+    Ok(())
+}

nursery/coin_select/src/coin_selector.rs

@@ -96,7 +96,7 @@ impl CoinSelectorOpt {
     ) -> Self {
         let mut tx = Transaction {
             input: vec![],
-            version: 1,
+            version: transaction::Version::ONE,
             lock_time: absolute::LockTime::ZERO,
             output: txouts.to_vec(),
         };
@@ -112,7 +112,7 @@ impl CoinSelectorOpt {
             target_value: if txouts.is_empty() {
                 None
             } else {
-                Some(txouts.iter().map(|txout| txout.value).sum())
+                Some(txouts.iter().map(|txout| txout.value.to_sat()).sum())
             },
             ..Self::from_weights(
                 base_weight.to_wu() as u32,

nursery/coin_select/src/lib.rs

@@ -12,7 +12,7 @@ use bdk_chain::{
     bitcoin,
     collections::{BTreeSet, HashMap},
 };
-use bitcoin::{absolute, Transaction, TxOut};
+use bitcoin::{absolute, transaction, Transaction, TxOut};
 use core::fmt::{Debug, Display};
 
 mod coin_selector;
@@ -29,5 +29,5 @@ pub const TXIN_BASE_WEIGHT: u32 = (32 + 4 + 4) * 4;
 // Shamelessly copied from
 // https://github.com/rust-bitcoin/rust-miniscript/blob/d5615acda1a7fdc4041a11c1736af139b8c7ebe8/src/util.rs#L8
 pub(crate) fn varint_size(v: usize) -> u32 {
-    bitcoin::VarInt(v as u64).len() as u32
+    bitcoin::VarInt(v as u64).size() as u32
 }

nursery/tmp_plan/src/lib.rs

@@ -17,14 +17,13 @@
 use bdk_chain::{bitcoin, collections::*, miniscript};
 use bitcoin::{
     absolute,
-    address::WitnessVersion,
     bip32::{DerivationPath, Fingerprint, KeySource},
     blockdata::transaction::Sequence,
     ecdsa,
     hashes::{hash160, ripemd160, sha256},
     secp256k1::Secp256k1,
     taproot::{self, LeafVersion, TapLeafHash},
-    ScriptBuf, TxIn, Witness,
+    ScriptBuf, TxIn, Witness, WitnessVersion,
 };
 use miniscript::{
     descriptor::{InnerXKey, Tr},
@@ -32,7 +31,7 @@ use miniscript::{
 };
 
 pub(crate) fn varint_len(v: usize) -> usize {
-    bitcoin::VarInt(v as u64).len() as usize
+    bitcoin::VarInt(v as u64).size() as usize
 }
 
 mod plan_impls;

nursery/tmp_plan/src/requirements.rs

@@ -3,12 +3,11 @@ use core::ops::Deref;
 
 use bitcoin::{
     bip32,
-    hashes::{hash160, ripemd160, sha256},
+    hashes::{hash160, ripemd160, sha256, Hash},
     key::XOnlyPublicKey,
-    psbt::Prevouts,
-    secp256k1::{KeyPair, Message, PublicKey, Signing, Verification},
+    secp256k1::{Keypair, Message, PublicKey, Signing, Verification},
     sighash,
-    sighash::{EcdsaSighashType, SighashCache, TapSighashType},
+    sighash::{EcdsaSighashType, Prevouts, SighashCache, TapSighashType},
     taproot, Transaction, TxOut,
 };
 
@@ -163,11 +162,11 @@ impl RequiredSignatures<DescriptorPublicKey> {
 
                 let tweak =
                     taproot::TapTweakHash::from_key_and_tweak(x_only_pubkey, merkle_root.clone());
-                let keypair = KeyPair::from_secret_key(&secp, &secret_key.clone())
+                let keypair = Keypair::from_secret_key(&secp, &secret_key.clone())
                     .add_xonly_tweak(&secp, &tweak.to_scalar())
                     .unwrap();
 
-                let msg = Message::from_slice(sighash.as_ref()).expect("Sighashes are 32 bytes");
+                let msg = Message::from_digest(sighash.to_byte_array());
                 let sig = secp.sign_schnorr_no_aux_rand(&msg, &keypair);
 
                 let bitcoin_sig = taproot::Signature {
@@ -209,9 +208,8 @@ impl RequiredSignatures<DescriptorPublicKey> {
                                 todo!();
                             }
                         };
-                        let keypair = KeyPair::from_secret_key(&secp, &secret_key.clone());
-                        let msg =
-                            Message::from_slice(sighash.as_ref()).expect("Sighashes are 32 bytes");
+                        let keypair = Keypair::from_secret_key(&secp, &secret_key.clone());
+                        let msg = Message::from_digest(sighash.to_byte_array());
                         let sig = secp.sign_schnorr_no_aux_rand(&msg, &keypair);
                         let bitcoin_sig = taproot::Signature {
                             sig,