Bump version to 0.20.0

92b9597f8b Rename `set_current_height` to `current_height` (Alekos Filini)

Pull request description:

  ### Description

  Usually we don't have any prefix except for methods that can *add* to a list or replace the list entirely (e.g. `add_recipients` vs `set_recipients`)

  I missed this during review of #611

  ### 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:
  danielabrozzoni:
    utACK 92b9597f8b - I'm sorry I didn't notice it!

Tree-SHA512: 3391068b2761bcd04d740ef41f9e772039fca7bc0e0736afcbc582ec74b6c91eb155d9e09dd7a07462eec29e32ac86e41ba339d9a550af3f754164cab6bdbf61

.github/workflows/cont_integration.yml

@@ -12,7 +12,7 @@ jobs:
         rust:
           - version: 1.60.0 # STABLE
             clippy: true
-          - version: 1.56.0 # MSRV
+          - version: 1.56.1 # MSRV
         features:
           - default
           - minimal
@@ -146,7 +146,7 @@ jobs:
       - run: sudo apt-get update || exit 1
       - run: sudo apt-get install -y libclang-common-10-dev clang-10 libc6-dev-i386 || exit 1
       - name: Set default toolchain
-        run: rustup default 1.56.0 # STABLE
+        run: rustup default 1.56.1 # STABLE
       - name: Set profile
         run: rustup set profile minimal
       - name: Add target wasm32

CHANGELOG.md

@@ -6,6 +6,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+
+## [v0.20.0] - [v0.19.0]
+
+- New MSRV set to `1.56.1`
+- Fee sniping discouraging through nLockTime - if the user specifies a `current_height`, we use that as a nlocktime, otherwise we use the last sync height (or 0 if we never synced)
+- Fix hang when `ElectrumBlockchainConfig::stop_gap` is zero.
+- Set coin type in BIP44, BIP49, and BIP84 templates
+- Get block hash given a block height - A `get_block_hash` method is now defined on the `GetBlockHash` trait and implemented on every blockchain backend. This method expects a block height and returns the corresponding block hash. 
+- Add `remove_partial_sigs` and `try_finalize` to `SignOptions`
+- Deprecate `AddressValidator`
+- Fix Electrum wallet sync potentially causing address index decrement - compare proposed index and current index before applying batch operations during sync.
+
 ## [v0.19.0] - [v0.18.0]
 
 - added `OldestFirstCoinSelection` impl to `CoinSelectionAlgorithm`
@@ -51,6 +63,7 @@ To decouple the `Wallet` from the `Blockchain` we've made major changes:
 - Stop making a request for the block height when calling `Wallet:new`.
 - Added `SyncOptions` to capture extra (future) arguments to `Wallet::sync`.
 - Removed `max_addresses` sync parameter which determined how many addresses to cache before syncing since this can just be done with `ensure_addresses_cached`.
+- remove `flush` method from the `Database` trait.
 
 ## [v0.16.1] - [v0.16.0]
 
@@ -465,4 +478,5 @@ final transaction is created by calling `finish` on the builder.
 [v0.17.0]: https://github.com/bitcoindevkit/bdk/compare/v0.16.1...v0.17.0
 [v0.18.0]: https://github.com/bitcoindevkit/bdk/compare/v0.17.0...v0.18.0
 [v0.19.0]: https://github.com/bitcoindevkit/bdk/compare/v0.18.0...v0.19.0
-[unreleased]: https://github.com/bitcoindevkit/bdk/compare/v0.19.0...HEAD
+[v0.20.0]: https://github.com/bitcoindevkit/bdk/compare/v0.19.0...v0.20.0
+[unreleased]: https://github.com/bitcoindevkit/bdk/compare/v0.20.0...HEAD

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bdk"
-version = "0.19.0"
+version = "0.20.0"
 edition = "2018"
 authors = ["Alekos Filini <alekos.filini@gmail.com>", "Riccardo Casatta <riccardo@casatta.it>"]
 homepage = "https://bitcoindevkit.org"
@@ -23,8 +23,8 @@ rand = "^0.7"
 # Optional dependencies
 sled = { version = "0.34", optional = true }
 electrum-client = { version = "0.10", optional = true }
-rusqlite = { version = "0.25.3", optional = true }
-ahash = { version = "=0.7.4", optional = true }
+rusqlite = { version = "0.27.0", optional = true }
+ahash = { version = "0.7.6", optional = true }
 reqwest = { version = "0.11", optional = true, default-features = false, features = ["json"] }
 ureq = { version = "~2.2.0", features = ["json"], optional = true }
 futures = { version = "0.3", optional = true }

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://codecov.io/gh/bitcoindevkit/bdk"><img src="https://codecov.io/gh/bitcoindevkit/bdk/branch/master/graph/badge.svg"/></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/2020/08/27/Rust-1.56.0.html"><img alt="Rustc Version 1.56+" src="https://img.shields.io/badge/rustc-1.56%2B-lightgrey.svg"/></a>
+    <a href="https://blog.rust-lang.org/2021/11/01/Rust-1.56.1.html"><img alt="Rustc Version 1.56.1+" src="https://img.shields.io/badge/rustc-1.56.1%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>
 

examples/address_validator.rs

@@ -14,6 +14,7 @@ use std::sync::Arc;
 use bdk::bitcoin;
 use bdk::database::MemoryDatabase;
 use bdk::descriptor::HdKeyPaths;
+#[allow(deprecated)]
 use bdk::wallet::address_validator::{AddressValidator, AddressValidatorError};
 use bdk::KeychainKind;
 use bdk::Wallet;
@@ -25,6 +26,7 @@ use bitcoin::{Network, Script};
 
 #[derive(Debug)]
 struct DummyValidator;
+#[allow(deprecated)]
 impl AddressValidator for DummyValidator {
     fn validate(
         &self,
@@ -50,6 +52,7 @@ fn main() -> Result<(), bdk::Error> {
     let descriptor = "sh(and_v(v:pk(tpubDDpWvmUrPZrhSPmUzCMBHffvC3HyMAPnWDSAQNBTnj1iZeJa7BZQEttFiP4DS4GCcXQHezdXhn86Hj6LHX5EDstXPWrMaSneRWM8yUf6NFd/*),after(630000)))";
     let mut wallet = Wallet::new(descriptor, None, Network::Regtest, MemoryDatabase::new())?;
 
+    #[allow(deprecated)]
     wallet.add_address_validator(Arc::new(DummyValidator));
 
     wallet.get_address(New)?;

src/blockchain/any.rs

@@ -120,6 +120,13 @@ impl GetTx for AnyBlockchain {
     }
 }
 
+#[maybe_async]
+impl GetBlockHash for AnyBlockchain {
+    fn get_block_hash(&self, height: u64) -> Result<BlockHash, Error> {
+        maybe_await!(impl_inner_method!(self, get_block_hash, height))
+    }
+}
+
 #[maybe_async]
 impl WalletSync for AnyBlockchain {
     fn wallet_sync<D: BatchDatabase>(

src/blockchain/compact_filters/mod.rs

@@ -260,6 +260,16 @@ impl GetTx for CompactFiltersBlockchain {
     }
 }
 
+impl GetBlockHash for CompactFiltersBlockchain {
+    fn get_block_hash(&self, height: u64) -> Result<BlockHash, Error> {
+        self.headers
+            .get_block_hash(height as usize)?
+            .ok_or(Error::CompactFilters(
+                CompactFiltersError::BlockHashNotFound,
+            ))
+    }
+}
+
 impl WalletSync for CompactFiltersBlockchain {
     #[allow(clippy::mutex_atomic)] // Mutex is easier to understand than a CAS loop.
     fn wallet_setup<D: BatchDatabase>(
@@ -536,6 +546,8 @@ pub enum CompactFiltersError {
     InvalidFilter,
     /// The peer is missing a block in the valid chain
     MissingBlock,
+    /// Block hash at specified height not found
+    BlockHashNotFound,
     /// The data stored in the block filters storage are corrupted
     DataCorruption,
 

src/blockchain/electrum.rs

@@ -98,6 +98,13 @@ impl GetTx for ElectrumBlockchain {
     }
 }
 
+impl GetBlockHash for ElectrumBlockchain {
+    fn get_block_hash(&self, height: u64) -> Result<BlockHash, Error> {
+        let block_header = self.client.block_header(height as usize)?;
+        Ok(block_header.block_hash())
+    }
+}
+
 impl WalletSync for ElectrumBlockchain {
     fn wallet_setup<D: BatchDatabase>(
         &self,
@@ -108,7 +115,10 @@ impl WalletSync for ElectrumBlockchain {
         let mut block_times = HashMap::<u32, u32>::new();
         let mut txid_to_height = HashMap::<Txid, u32>::new();
         let mut tx_cache = TxCache::new(database, &self.client);
-        let chunk_size = self.stop_gap;
+
+        // Set chunk_size to the smallest value capable of finding a gap greater than stop_gap.
+        let chunk_size = self.stop_gap + 1;
+
         // The electrum server has been inconsistent somehow in its responses during sync. For
         // example, we do a batch request of transactions and the response contains less
         // tranascations than in the request. This should never happen but we don't want to panic.
@@ -144,21 +154,12 @@ impl WalletSync for ElectrumBlockchain {
 
                 Request::Conftime(conftime_req) => {
                     // collect up to chunk_size heights to fetch from electrum
-                    let needs_block_height = {
-                        let mut needs_block_height_iter = conftime_req
-                            .request()
-                            .filter_map(|txid| txid_to_height.get(txid).cloned())
-                            .filter(|height| block_times.get(height).is_none());
-                        let mut needs_block_height = HashSet::new();
-
-                        while needs_block_height.len() < chunk_size {
-                            match needs_block_height_iter.next() {
-                                Some(height) => needs_block_height.insert(height),
-                                None => break,
-                            };
-                        }
-                        needs_block_height
-                    };
+                    let needs_block_height = conftime_req
+                        .request()
+                        .filter_map(|txid| txid_to_height.get(txid).cloned())
+                        .filter(|height| block_times.get(height).is_none())
+                        .take(chunk_size)
+                        .collect::<HashSet<u32>>();
 
                     let new_block_headers = self
                         .client
@@ -328,6 +329,7 @@ mod test {
     use super::*;
     use crate::database::MemoryDatabase;
     use crate::testutils::blockchain_tests::TestClient;
+    use crate::testutils::configurable_blockchain_tests::ConfigurableBlockchainTester;
     use crate::wallet::{AddressIndex, Wallet};
 
     crate::bdk_blockchain_tests! {
@@ -385,4 +387,29 @@ mod test {
 
         assert_eq!(wallet.get_balance().unwrap(), 50_000);
     }
+
+    #[test]
+    fn test_electrum_with_variable_configs() {
+        struct ElectrumTester;
+
+        impl ConfigurableBlockchainTester<ElectrumBlockchain> for ElectrumTester {
+            const BLOCKCHAIN_NAME: &'static str = "Electrum";
+
+            fn config_with_stop_gap(
+                &self,
+                test_client: &mut TestClient,
+                stop_gap: usize,
+            ) -> Option<ElectrumBlockchainConfig> {
+                Some(ElectrumBlockchainConfig {
+                    url: test_client.electrsd.electrum_url.clone(),
+                    socks5: None,
+                    retry: 0,
+                    timeout: None,
+                    stop_gap: stop_gap,
+                })
+            }
+        }
+
+        ElectrumTester.run();
+    }
 }

src/blockchain/esplora/mod.rs

@@ -209,4 +209,38 @@ mod test {
             "should inherit from value for 25"
         );
     }
+
+    #[test]
+    #[cfg(feature = "test-esplora")]
+    fn test_esplora_with_variable_configs() {
+        use crate::testutils::{
+            blockchain_tests::TestClient,
+            configurable_blockchain_tests::ConfigurableBlockchainTester,
+        };
+
+        struct EsploraTester;
+
+        impl ConfigurableBlockchainTester<EsploraBlockchain> for EsploraTester {
+            const BLOCKCHAIN_NAME: &'static str = "Esplora";
+
+            fn config_with_stop_gap(
+                &self,
+                test_client: &mut TestClient,
+                stop_gap: usize,
+            ) -> Option<EsploraBlockchainConfig> {
+                Some(EsploraBlockchainConfig {
+                    base_url: format!(
+                        "http://{}",
+                        test_client.electrsd.esplora_url.as_ref().unwrap()
+                    ),
+                    proxy: None,
+                    concurrency: None,
+                    stop_gap: stop_gap,
+                    timeout: None,
+                })
+            }
+        }
+
+        EsploraTester.run();
+    }
 }

src/blockchain/esplora/reqwest.rs

@@ -117,6 +117,14 @@ impl GetTx for EsploraBlockchain {
     }
 }
 
+#[maybe_async]
+impl GetBlockHash for EsploraBlockchain {
+    fn get_block_hash(&self, height: u64) -> Result<BlockHash, Error> {
+        let block_header = await_or_block!(self.url_client._get_header(height as u32))?;
+        Ok(block_header.block_hash())
+    }
+}
+
 #[maybe_async]
 impl WalletSync for EsploraBlockchain {
     fn wallet_setup<D: BatchDatabase>(

src/blockchain/esplora/ureq.rs

@@ -88,7 +88,7 @@ impl Blockchain for EsploraBlockchain {
     }
 
     fn broadcast(&self, tx: &Transaction) -> Result<(), Error> {
-        let _txid = self.url_client._broadcast(tx)?;
+        self.url_client._broadcast(tx)?;
         Ok(())
     }
 
@@ -112,6 +112,13 @@ impl GetTx for EsploraBlockchain {
     }
 }
 
+impl GetBlockHash for EsploraBlockchain {
+    fn get_block_hash(&self, height: u64) -> Result<BlockHash, Error> {
+        let block_header = self.url_client._get_header(height as u32)?;
+        Ok(block_header.block_hash())
+    }
+}
+
 impl WalletSync for EsploraBlockchain {
     fn wallet_setup<D: BatchDatabase>(
         &self,

src/blockchain/mod.rs

@@ -21,7 +21,7 @@ use std::ops::Deref;
 use std::sync::mpsc::{channel, Receiver, Sender};
 use std::sync::Arc;
 
-use bitcoin::{Transaction, Txid};
+use bitcoin::{BlockHash, Transaction, Txid};
 
 use crate::database::BatchDatabase;
 use crate::error::Error;
@@ -87,7 +87,7 @@ pub enum Capability {
 
 /// Trait that defines the actions that must be supported by a blockchain backend
 #[maybe_async]
-pub trait Blockchain: WalletSync + GetHeight + GetTx {
+pub trait Blockchain: WalletSync + GetHeight + GetTx + GetBlockHash {
     /// Return the set of [`Capability`] supported by this backend
     fn get_capabilities(&self) -> HashSet<Capability>;
     /// Broadcast a transaction
@@ -110,6 +110,13 @@ pub trait GetTx {
     fn get_tx(&self, txid: &Txid) -> Result<Option<Transaction>, Error>;
 }
 
+#[maybe_async]
+/// Trait for getting block hash by block height
+pub trait GetBlockHash {
+    /// fetch block hash given its height
+    fn get_block_hash(&self, height: u64) -> Result<BlockHash, Error>;
+}
+
 /// Trait for blockchains that can sync by updating the database directly.
 #[maybe_async]
 pub trait WalletSync {
@@ -359,6 +366,13 @@ impl<T: GetHeight> GetHeight for Arc<T> {
     }
 }
 
+#[maybe_async]
+impl<T: GetBlockHash> GetBlockHash for Arc<T> {
+    fn get_block_hash(&self, height: u64) -> Result<BlockHash, Error> {
+        maybe_await!(self.deref().get_block_hash(height))
+    }
+}
+
 #[maybe_async]
 impl<T: WalletSync> WalletSync for Arc<T> {
     fn wallet_setup<D: BatchDatabase>(

src/blockchain/rpc.rs

@@ -169,6 +169,12 @@ impl GetHeight for RpcBlockchain {
     }
 }
 
+impl GetBlockHash for RpcBlockchain {
+    fn get_block_hash(&self, height: u64) -> Result<BlockHash, Error> {
+        Ok(self.client.get_block_hash(height)?)
+    }
+}
+
 impl WalletSync for RpcBlockchain {
     fn wallet_setup<D: BatchDatabase>(
         &self,
@@ -334,7 +340,7 @@ impl WalletSync for RpcBlockchain {
                     ),
                     received,
                     sent,
-                    fee: tx_result.fee.map(|f| f.as_sat().abs() as u64),
+                    fee: tx_result.fee.map(|f| f.as_sat().unsigned_abs()),
                 };
                 debug!(
                     "saving tx: {} tx_result.fee:{:?} td.fees:{:?}",

src/blockchain/script_sync.rs

@@ -314,6 +314,22 @@ impl<'a, D: BatchDatabase> State<'a, D> {
         let finished_txs = make_txs_consistent(&self.finished_txs);
         let observed_txids: HashSet<Txid> = finished_txs.iter().map(|tx| tx.txid).collect();
         let txids_to_delete = existing_txids.difference(&observed_txids);
+
+        // Ensure `last_active_index` does not decrement database's current state.
+        let index_updates = self
+            .last_active_index
+            .iter()
+            .map(|(keychain, sync_index)| {
+                let sync_index = *sync_index as u32;
+                let index_res = match self.db.get_last_index(*keychain) {
+                    Ok(Some(db_index)) => Ok(std::cmp::max(db_index, sync_index)),
+                    Ok(None) => Ok(sync_index),
+                    Err(err) => Err(err),
+                };
+                index_res.map(|index| (*keychain, index))
+            })
+            .collect::<Result<Vec<(KeychainKind, u32)>, _>>()?;
+
         let mut batch = self.db.begin_batch();
 
         // Delete old txs that no longer exist
@@ -377,8 +393,10 @@ impl<'a, D: BatchDatabase> State<'a, D> {
             batch.set_tx(finished_tx)?;
         }
 
-        for (keychain, last_active_index) in self.last_active_index {
-            batch.set_last_index(keychain, last_active_index as u32)?;
+        // apply index updates
+        for (keychain, new_index) in index_updates {
+            debug!("updating index ({}, {})", keychain.as_byte(), new_index);
+            batch.set_last_index(keychain, new_index)?;
         }
 
         info!(

src/database/any.rs

@@ -255,10 +255,6 @@ impl Database for AnyDatabase {
     fn increment_last_index(&mut self, keychain: KeychainKind) -> Result<u32, Error> {
         impl_inner_method!(AnyDatabase, self, increment_last_index, keychain)
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        impl_inner_method!(AnyDatabase, self, flush)
-    }
 }
 
 impl BatchOperations for AnyBatch {

src/database/keyvalue.rs

@@ -166,16 +166,9 @@ macro_rules! impl_batch_operations {
         fn del_last_index(&mut self, keychain: KeychainKind) -> Result<Option<u32>, Error> {
             let key = MapKey::LastIndex(keychain).as_map_key();
             let res = self.remove(key);
-            let res = $process_delete!(res);
-
-            match res {
-                None => Ok(None),
-                Some(b) => {
-                    let array: [u8; 4] = b.as_ref().try_into().map_err(|_| Error::InvalidU32Bytes(b.to_vec()))?;
-                    let val = u32::from_be_bytes(array);
-                    Ok(Some(val))
-                }
-            }
+            $process_delete!(res)
+            .map(ivec_to_u32)
+            .transpose()
         }
 
         fn del_sync_time(&mut self) -> Result<Option<SyncTime>, Error> {
@@ -357,16 +350,7 @@ impl Database for Tree {
 
     fn get_last_index(&self, keychain: KeychainKind) -> Result<Option<u32>, Error> {
         let key = MapKey::LastIndex(keychain).as_map_key();
-        self.get(key)?
-            .map(|b| -> Result<_, Error> {
-                let array: [u8; 4] = b
-                    .as_ref()
-                    .try_into()
-                    .map_err(|_| Error::InvalidU32Bytes(b.to_vec()))?;
-                let val = u32::from_be_bytes(array);
-                Ok(val)
-            })
-            .transpose()
+        self.get(key)?.map(ivec_to_u32).transpose()
     }
 
     fn get_sync_time(&self) -> Result<Option<SyncTime>, Error> {
@@ -393,19 +377,17 @@ impl Database for Tree {
 
             Some(new.to_be_bytes().to_vec())
         })?
-        .map_or(Ok(0), |b| -> Result<_, Error> {
-            let array: [u8; 4] = b
-                .as_ref()
-                .try_into()
-                .map_err(|_| Error::InvalidU32Bytes(b.to_vec()))?;
-            let val = u32::from_be_bytes(array);
-            Ok(val)
-        })
+        .map_or(Ok(0), ivec_to_u32)
     }
+}
 
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(Tree::flush(self).map(|_| ())?)
-    }
+fn ivec_to_u32(b: sled::IVec) -> Result<u32, Error> {
+    let array: [u8; 4] = b
+        .as_ref()
+        .try_into()
+        .map_err(|_| Error::InvalidU32Bytes(b.to_vec()))?;
+    let val = u32::from_be_bytes(array);
+    Ok(val)
 }
 
 impl BatchDatabase for Tree {

src/database/memory.rs

@@ -449,10 +449,6 @@ impl Database for MemoryDatabase {
 
         Ok(*value)
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(())
-    }
 }
 
 impl BatchDatabase for MemoryDatabase {
@@ -486,15 +482,23 @@ impl ConfigurableDatabase for MemoryDatabase {
 /// don't have `test` set.
 macro_rules! populate_test_db {
     ($db:expr, $tx_meta:expr, $current_height:expr$(,)?) => {{
+        $crate::populate_test_db!($db, $tx_meta, $current_height, (@coinbase false))
+    }};
+    ($db:expr, $tx_meta:expr, $current_height:expr, (@coinbase $is_coinbase:expr)$(,)?) => {{
         use std::str::FromStr;
         use $crate::database::BatchOperations;
         let mut db = $db;
         let tx_meta = $tx_meta;
         let current_height: Option<u32> = $current_height;
+        let input = if $is_coinbase {
+            vec![$crate::bitcoin::TxIn::default()]
+        } else {
+            vec![]
+        };
         let tx = $crate::bitcoin::Transaction {
             version: 1,
             lock_time: 0,
-            input: vec![],
+            input,
             output: tx_meta
                 .output
                 .iter()
@@ -508,10 +512,13 @@ macro_rules! populate_test_db {
         };
 
         let txid = tx.txid();
-        let confirmation_time = tx_meta.min_confirmations.map(|conf| $crate::BlockTime {
-            height: current_height.unwrap().checked_sub(conf as u32).unwrap(),
-            timestamp: 0,
-        });
+        let confirmation_time = tx_meta
+            .min_confirmations
+            .and_then(|v| if v == 0 { None } else { Some(v) })
+            .map(|conf| $crate::BlockTime {
+                height: current_height.unwrap().checked_sub(conf as u32).unwrap() + 1,
+                timestamp: 0,
+            });
 
         let tx_details = $crate::TransactionDetails {
             transaction: Some(tx.clone()),

src/database/mod.rs

@@ -158,13 +158,6 @@ pub trait Database: BatchOperations {
     ///
     /// It should insert and return `0` if not present in the database
     fn increment_last_index(&mut self, keychain: KeychainKind) -> Result<u32, Error>;
-
-    #[deprecated(
-        since = "0.18.0",
-        note = "The flush function is only needed for the sled database on mobile, instead for mobile use the sqlite database."
-    )]
-    /// Force changes to be written to disk
-    fn flush(&mut self) -> Result<(), Error>;
 }
 
 /// Trait for a database that supports batch operations

src/database/sqlite.rs

@@ -891,10 +891,6 @@ impl Database for SqliteDatabase {
             }
         }
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(())
-    }
 }
 
 impl BatchDatabase for SqliteDatabase {

src/descriptor/mod.rs

@@ -134,13 +134,13 @@ impl IntoWalletDescriptor for (ExtendedDescriptor, KeyMap) {
 
         let check_key = |pk: &DescriptorPublicKey| {
             let (pk, _, networks) = if self.0.is_witness() {
-                let desciptor_key: DescriptorKey<miniscript::Segwitv0> =
+                let descriptor_key: DescriptorKey<miniscript::Segwitv0> =
                     pk.clone().into_descriptor_key()?;
-                desciptor_key.extract(secp)?
+                descriptor_key.extract(secp)?
             } else {
-                let desciptor_key: DescriptorKey<miniscript::Legacy> =
+                let descriptor_key: DescriptorKey<miniscript::Legacy> =
                     pk.clone().into_descriptor_key()?;
-                desciptor_key.extract(secp)?
+                descriptor_key.extract(secp)?
             };
 
             if networks.contains(&network) {

src/descriptor/template.rs

@@ -40,18 +40,19 @@ pub type DescriptorTemplateOut = (ExtendedDescriptor, KeyMap, ValidNetworks);
 /// use bdk::keys::{IntoDescriptorKey, KeyError};
 /// use bdk::miniscript::Legacy;
 /// use bdk::template::{DescriptorTemplate, DescriptorTemplateOut};
+/// use bitcoin::Network;
 ///
 /// struct MyP2PKH<K: IntoDescriptorKey<Legacy>>(K);
 ///
 /// impl<K: IntoDescriptorKey<Legacy>> DescriptorTemplate for MyP2PKH<K> {
-///     fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
+///     fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
 ///         Ok(bdk::descriptor!(pkh(self.0))?)
 ///     }
 /// }
 /// ```
 pub trait DescriptorTemplate {
     /// Build the complete descriptor
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError>;
+    fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError>;
 }
 
 /// Turns a [`DescriptorTemplate`] into a valid wallet descriptor by calling its
@@ -62,7 +63,7 @@ impl<T: DescriptorTemplate> IntoWalletDescriptor for T {
         secp: &SecpCtx,
         network: Network,
     ) -> Result<(ExtendedDescriptor, KeyMap), DescriptorError> {
-        self.build()?.into_wallet_descriptor(secp, network)
+        self.build(network)?.into_wallet_descriptor(secp, network)
     }
 }
 
@@ -95,7 +96,7 @@ impl<T: DescriptorTemplate> IntoWalletDescriptor for T {
 pub struct P2Pkh<K: IntoDescriptorKey<Legacy>>(pub K);
 
 impl<K: IntoDescriptorKey<Legacy>> DescriptorTemplate for P2Pkh<K> {
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
+    fn build(self, _network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
         descriptor!(pkh(self.0))
     }
 }
@@ -130,7 +131,7 @@ impl<K: IntoDescriptorKey<Legacy>> DescriptorTemplate for P2Pkh<K> {
 pub struct P2Wpkh_P2Sh<K: IntoDescriptorKey<Segwitv0>>(pub K);
 
 impl<K: IntoDescriptorKey<Segwitv0>> DescriptorTemplate for P2Wpkh_P2Sh<K> {
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
+    fn build(self, _network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
         descriptor!(sh(wpkh(self.0)))
     }
 }
@@ -164,12 +165,12 @@ impl<K: IntoDescriptorKey<Segwitv0>> DescriptorTemplate for P2Wpkh_P2Sh<K> {
 pub struct P2Wpkh<K: IntoDescriptorKey<Segwitv0>>(pub K);
 
 impl<K: IntoDescriptorKey<Segwitv0>> DescriptorTemplate for P2Wpkh<K> {
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
+    fn build(self, _network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
         descriptor!(wpkh(self.0))
     }
 }
 
-/// BIP44 template. Expands to `pkh(key/44'/0'/0'/{0,1}/*)`
+/// BIP44 template. Expands to `pkh(key/44'/{0,1}'/0'/{0,1}/*)`
 ///
 /// Since there are hardened derivation steps, this template requires a private derivable key (generally a `xprv`/`tprv`).
 ///
@@ -193,21 +194,21 @@ impl<K: IntoDescriptorKey<Segwitv0>> DescriptorTemplate for P2Wpkh<K> {
 ///     MemoryDatabase::default()
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New)?.to_string(), "miNG7dJTzJqNbFS19svRdTCisC65dsubtR");
-/// assert_eq!(wallet.public_descriptor(KeychainKind::External)?.unwrap().to_string(), "pkh([c55b303f/44'/0'/0']tpubDDDzQ31JkZB7VxUr9bjvBivDdqoFLrDPyLWtLapArAi51ftfmCb2DPxwLQzX65iNcXz1DGaVvyvo6JQ6rTU73r2gqdEo8uov9QKRb7nKCSU/0/*)#xgaaevjx");
+/// assert_eq!(wallet.get_address(New)?.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>>(())
 /// ```
 pub struct Bip44<K: DerivableKey<Legacy>>(pub K, pub KeychainKind);
 
 impl<K: DerivableKey<Legacy>> DescriptorTemplate for Bip44<K> {
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
-        P2Pkh(legacy::make_bipxx_private(44, self.0, self.1)?).build()
+    fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
+        P2Pkh(legacy::make_bipxx_private(44, self.0, self.1, network)?).build(network)
     }
 }
 
 /// BIP44 public template. Expands to `pkh(key/{0,1}/*)`
 ///
-/// This assumes that the key used has already been derived with `m/44'/0'/0'`.
+/// This assumes that the key used has already been derived with `m/44'/0'/0'` for Mainnet or `m/44'/1'/0'` for Testnet.
 ///
 /// This template requires the parent fingerprint to populate correctly the metadata of PSBTs.
 ///
@@ -240,12 +241,12 @@ impl<K: DerivableKey<Legacy>> DescriptorTemplate for Bip44<K> {
 pub struct Bip44Public<K: DerivableKey<Legacy>>(pub K, pub bip32::Fingerprint, pub KeychainKind);
 
 impl<K: DerivableKey<Legacy>> DescriptorTemplate for Bip44Public<K> {
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
-        P2Pkh(legacy::make_bipxx_public(44, self.0, self.1, self.2)?).build()
+    fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
+        P2Pkh(legacy::make_bipxx_public(44, self.0, self.1, self.2)?).build(network)
     }
 }
 
-/// BIP49 template. Expands to `sh(wpkh(key/49'/0'/0'/{0,1}/*))`
+/// BIP49 template. Expands to `sh(wpkh(key/49'/{0,1}'/0'/{0,1}/*))`
 ///
 /// Since there are hardened derivation steps, this template requires a private derivable key (generally a `xprv`/`tprv`).
 ///
@@ -269,15 +270,15 @@ impl<K: DerivableKey<Legacy>> DescriptorTemplate for Bip44Public<K> {
 ///     MemoryDatabase::default()
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New)?.to_string(), "2N3K4xbVAHoiTQSwxkZjWDfKoNC27pLkYnt");
-/// assert_eq!(wallet.public_descriptor(KeychainKind::External)?.unwrap().to_string(), "sh(wpkh([c55b303f/49\'/0\'/0\']tpubDC49r947KGK52X5rBWS4BLs5m9SRY3pYHnvRrm7HcybZ3BfdEsGFyzCMzayi1u58eT82ZeyFZwH7DD6Q83E3fM9CpfMtmnTygnLfP59jL9L/0/*))#gsmdv4xr");
+/// assert_eq!(wallet.get_address(New)?.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>>(())
 /// ```
 pub struct Bip49<K: DerivableKey<Segwitv0>>(pub K, pub KeychainKind);
 
 impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip49<K> {
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
-        P2Wpkh_P2Sh(segwit_v0::make_bipxx_private(49, self.0, self.1)?).build()
+    fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
+        P2Wpkh_P2Sh(segwit_v0::make_bipxx_private(49, self.0, self.1, network)?).build(network)
     }
 }
 
@@ -310,18 +311,18 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip49<K> {
 /// )?;
 ///
 /// assert_eq!(wallet.get_address(New)?.to_string(), "2N3K4xbVAHoiTQSwxkZjWDfKoNC27pLkYnt");
-/// assert_eq!(wallet.public_descriptor(KeychainKind::External)?.unwrap().to_string(), "sh(wpkh([c55b303f/49\'/0\'/0\']tpubDC49r947KGK52X5rBWS4BLs5m9SRY3pYHnvRrm7HcybZ3BfdEsGFyzCMzayi1u58eT82ZeyFZwH7DD6Q83E3fM9CpfMtmnTygnLfP59jL9L/0/*))#gsmdv4xr");
+/// assert_eq!(wallet.public_descriptor(KeychainKind::External)?.unwrap().to_string(), "sh(wpkh([c55b303f/49'/0'/0']tpubDC49r947KGK52X5rBWS4BLs5m9SRY3pYHnvRrm7HcybZ3BfdEsGFyzCMzayi1u58eT82ZeyFZwH7DD6Q83E3fM9CpfMtmnTygnLfP59jL9L/0/*))#gsmdv4xr");
 /// # Ok::<_, Box<dyn std::error::Error>>(())
 /// ```
 pub struct Bip49Public<K: DerivableKey<Segwitv0>>(pub K, pub bip32::Fingerprint, pub KeychainKind);
 
 impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip49Public<K> {
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
-        P2Wpkh_P2Sh(segwit_v0::make_bipxx_public(49, self.0, self.1, self.2)?).build()
+    fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
+        P2Wpkh_P2Sh(segwit_v0::make_bipxx_public(49, self.0, self.1, self.2)?).build(network)
     }
 }
 
-/// BIP84 template. Expands to `wpkh(key/84'/0'/0'/{0,1}/*)`
+/// BIP84 template. Expands to `wpkh(key/84'/{0,1}'/0'/{0,1}/*)`
 ///
 /// Since there are hardened derivation steps, this template requires a private derivable key (generally a `xprv`/`tprv`).
 ///
@@ -345,15 +346,15 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip49Public<K> {
 ///     MemoryDatabase::default()
 /// )?;
 ///
-/// assert_eq!(wallet.get_address(New)?.to_string(), "tb1qedg9fdlf8cnnqfd5mks6uz5w4kgpk2pr6y4qc7");
-/// assert_eq!(wallet.public_descriptor(KeychainKind::External)?.unwrap().to_string(), "wpkh([c55b303f/84\'/0\'/0\']tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q/0/*)#nkk5dtkg");
+/// assert_eq!(wallet.get_address(New)?.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>>(())
 /// ```
 pub struct Bip84<K: DerivableKey<Segwitv0>>(pub K, pub KeychainKind);
 
 impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip84<K> {
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
-        P2Wpkh(segwit_v0::make_bipxx_private(84, self.0, self.1)?).build()
+    fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
+        P2Wpkh(segwit_v0::make_bipxx_private(84, self.0, self.1, network)?).build(network)
     }
 }
 
@@ -392,8 +393,8 @@ impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip84<K> {
 pub struct Bip84Public<K: DerivableKey<Segwitv0>>(pub K, pub bip32::Fingerprint, pub KeychainKind);
 
 impl<K: DerivableKey<Segwitv0>> DescriptorTemplate for Bip84Public<K> {
-    fn build(self) -> Result<DescriptorTemplateOut, DescriptorError> {
-        P2Wpkh(segwit_v0::make_bipxx_public(84, self.0, self.1, self.2)?).build()
+    fn build(self, network: Network) -> Result<DescriptorTemplateOut, DescriptorError> {
+        P2Wpkh(segwit_v0::make_bipxx_public(84, self.0, self.1, self.2)?).build(network)
     }
 }
 
@@ -406,10 +407,19 @@ macro_rules! expand_make_bipxx {
                 bip: u32,
                 key: K,
                 keychain: KeychainKind,
+                network: Network,
             ) -> Result<impl IntoDescriptorKey<$ctx>, DescriptorError> {
                 let mut derivation_path = Vec::with_capacity(4);
                 derivation_path.push(bip32::ChildNumber::from_hardened_idx(bip)?);
-                derivation_path.push(bip32::ChildNumber::from_hardened_idx(0)?);
+
+                match network {
+                    Network::Bitcoin => {
+                        derivation_path.push(bip32::ChildNumber::from_hardened_idx(0)?);
+                    }
+                    _ => {
+                        derivation_path.push(bip32::ChildNumber::from_hardened_idx(1)?);
+                    }
+                }
                 derivation_path.push(bip32::ChildNumber::from_hardened_idx(0)?);
 
                 match keychain {
@@ -466,6 +476,40 @@ mod test {
     use miniscript::descriptor::{DescriptorPublicKey, DescriptorTrait, KeyMap};
     use miniscript::Descriptor;
 
+    // BIP44 `pkh(key/44'/{0,1}'/0'/{0,1}/*)`
+    #[test]
+    fn test_bip44_template_cointype() {
+        use bitcoin::util::bip32::ChildNumber::{self, Hardened};
+
+        let xprvkey = bitcoin::util::bip32::ExtendedPrivKey::from_str("xprv9s21ZrQH143K2fpbqApQL69a4oKdGVnVN52R82Ft7d1pSqgKmajF62acJo3aMszZb6qQ22QsVECSFxvf9uyxFUvFYQMq3QbtwtRSMjLAhMf").unwrap();
+        assert_eq!(Network::Bitcoin, xprvkey.network);
+        let xdesc = Bip44(xprvkey, KeychainKind::Internal)
+            .build(Network::Bitcoin)
+            .unwrap();
+
+        if let ExtendedDescriptor::Pkh(pkh) = xdesc.0 {
+            let path: Vec<ChildNumber> = pkh.into_inner().full_derivation_path().into();
+            let purpose = path.get(0).unwrap();
+            assert!(matches!(purpose, Hardened { index: 44 }));
+            let coin_type = path.get(1).unwrap();
+            assert!(matches!(coin_type, Hardened { index: 0 }));
+        }
+
+        let tprvkey = bitcoin::util::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
+        assert_eq!(Network::Testnet, tprvkey.network);
+        let tdesc = Bip44(tprvkey, KeychainKind::Internal)
+            .build(Network::Testnet)
+            .unwrap();
+
+        if let ExtendedDescriptor::Pkh(pkh) = tdesc.0 {
+            let path: Vec<ChildNumber> = pkh.into_inner().full_derivation_path().into();
+            let purpose = path.get(0).unwrap();
+            assert!(matches!(purpose, Hardened { index: 44 }));
+            let coin_type = path.get(1).unwrap();
+            assert!(matches!(coin_type, Hardened { index: 1 }));
+        }
+    }
+
     // verify template descriptor generates expected address(es)
     fn check(
         desc: Result<(Descriptor<DescriptorPublicKey>, KeyMap, ValidNetworks), DescriptorError>,
@@ -497,7 +541,7 @@ mod test {
             bitcoin::PrivateKey::from_wif("cTc4vURSzdx6QE6KVynWGomDbLaA75dNALMNyfjh3p8DRRar84Um")
                 .unwrap();
         check(
-            P2Pkh(prvkey).build(),
+            P2Pkh(prvkey).build(Network::Bitcoin),
             false,
             true,
             &["mwJ8hxFYW19JLuc65RCTaP4v1rzVU8cVMT"],
@@ -508,7 +552,7 @@ mod test {
         )
         .unwrap();
         check(
-            P2Pkh(pubkey).build(),
+            P2Pkh(pubkey).build(Network::Bitcoin),
             false,
             true,
             &["muZpTpBYhxmRFuCjLc7C6BBDF32C8XVJUi"],
@@ -522,7 +566,7 @@ mod test {
             bitcoin::PrivateKey::from_wif("cTc4vURSzdx6QE6KVynWGomDbLaA75dNALMNyfjh3p8DRRar84Um")
                 .unwrap();
         check(
-            P2Wpkh_P2Sh(prvkey).build(),
+            P2Wpkh_P2Sh(prvkey).build(Network::Bitcoin),
             true,
             true,
             &["2NB4ox5VDRw1ecUv6SnT3VQHPXveYztRqk5"],
@@ -533,7 +577,7 @@ mod test {
         )
         .unwrap();
         check(
-            P2Wpkh_P2Sh(pubkey).build(),
+            P2Wpkh_P2Sh(pubkey).build(Network::Bitcoin),
             true,
             true,
             &["2N5LiC3CqzxDamRTPG1kiNv1FpNJQ7x28sb"],
@@ -547,7 +591,7 @@ mod test {
             bitcoin::PrivateKey::from_wif("cTc4vURSzdx6QE6KVynWGomDbLaA75dNALMNyfjh3p8DRRar84Um")
                 .unwrap();
         check(
-            P2Wpkh(prvkey).build(),
+            P2Wpkh(prvkey).build(Network::Bitcoin),
             true,
             true,
             &["bcrt1q4525hmgw265tl3drrl8jjta7ayffu6jfcwxx9y"],
@@ -558,7 +602,7 @@ mod test {
         )
         .unwrap();
         check(
-            P2Wpkh(pubkey).build(),
+            P2Wpkh(pubkey).build(Network::Bitcoin),
             true,
             true,
             &["bcrt1qngw83fg8dz0k749cg7k3emc7v98wy0c7azaa6h"],
@@ -570,7 +614,7 @@ mod test {
     fn test_bip44_template() {
         let prvkey = bitcoin::util::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         check(
-            Bip44(prvkey, KeychainKind::External).build(),
+            Bip44(prvkey, KeychainKind::External).build(Network::Bitcoin),
             false,
             false,
             &[
@@ -580,7 +624,7 @@ mod test {
             ],
         );
         check(
-            Bip44(prvkey, KeychainKind::Internal).build(),
+            Bip44(prvkey, KeychainKind::Internal).build(Network::Bitcoin),
             false,
             false,
             &[
@@ -597,7 +641,7 @@ mod test {
         let pubkey = bitcoin::util::bip32::ExtendedPubKey::from_str("tpubDDDzQ31JkZB7VxUr9bjvBivDdqoFLrDPyLWtLapArAi51ftfmCb2DPxwLQzX65iNcXz1DGaVvyvo6JQ6rTU73r2gqdEo8uov9QKRb7nKCSU").unwrap();
         let fingerprint = bitcoin::util::bip32::Fingerprint::from_str("c55b303f").unwrap();
         check(
-            Bip44Public(pubkey, fingerprint, KeychainKind::External).build(),
+            Bip44Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
             false,
             false,
             &[
@@ -607,7 +651,7 @@ mod test {
             ],
         );
         check(
-            Bip44Public(pubkey, fingerprint, KeychainKind::Internal).build(),
+            Bip44Public(pubkey, fingerprint, KeychainKind::Internal).build(Network::Bitcoin),
             false,
             false,
             &[
@@ -623,7 +667,7 @@ mod test {
     fn test_bip49_template() {
         let prvkey = bitcoin::util::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         check(
-            Bip49(prvkey, KeychainKind::External).build(),
+            Bip49(prvkey, KeychainKind::External).build(Network::Bitcoin),
             true,
             false,
             &[
@@ -633,7 +677,7 @@ mod test {
             ],
         );
         check(
-            Bip49(prvkey, KeychainKind::Internal).build(),
+            Bip49(prvkey, KeychainKind::Internal).build(Network::Bitcoin),
             true,
             false,
             &[
@@ -650,7 +694,7 @@ mod test {
         let pubkey = bitcoin::util::bip32::ExtendedPubKey::from_str("tpubDC49r947KGK52X5rBWS4BLs5m9SRY3pYHnvRrm7HcybZ3BfdEsGFyzCMzayi1u58eT82ZeyFZwH7DD6Q83E3fM9CpfMtmnTygnLfP59jL9L").unwrap();
         let fingerprint = bitcoin::util::bip32::Fingerprint::from_str("c55b303f").unwrap();
         check(
-            Bip49Public(pubkey, fingerprint, KeychainKind::External).build(),
+            Bip49Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
             true,
             false,
             &[
@@ -660,7 +704,7 @@ mod test {
             ],
         );
         check(
-            Bip49Public(pubkey, fingerprint, KeychainKind::Internal).build(),
+            Bip49Public(pubkey, fingerprint, KeychainKind::Internal).build(Network::Bitcoin),
             true,
             false,
             &[
@@ -676,7 +720,7 @@ mod test {
     fn test_bip84_template() {
         let prvkey = bitcoin::util::bip32::ExtendedPrivKey::from_str("tprv8ZgxMBicQKsPcx5nBGsR63Pe8KnRUqmbJNENAfGftF3yuXoMMoVJJcYeUw5eVkm9WBPjWYt6HMWYJNesB5HaNVBaFc1M6dRjWSYnmewUMYy").unwrap();
         check(
-            Bip84(prvkey, KeychainKind::External).build(),
+            Bip84(prvkey, KeychainKind::External).build(Network::Bitcoin),
             true,
             false,
             &[
@@ -686,7 +730,7 @@ mod test {
             ],
         );
         check(
-            Bip84(prvkey, KeychainKind::Internal).build(),
+            Bip84(prvkey, KeychainKind::Internal).build(Network::Bitcoin),
             true,
             false,
             &[
@@ -703,7 +747,7 @@ mod test {
         let pubkey = bitcoin::util::bip32::ExtendedPubKey::from_str("tpubDC2Qwo2TFsaNC4ju8nrUJ9mqVT3eSgdmy1yPqhgkjwmke3PRXutNGRYAUo6RCHTcVQaDR3ohNU9we59brGHuEKPvH1ags2nevW5opEE9Z5Q").unwrap();
         let fingerprint = bitcoin::util::bip32::Fingerprint::from_str("c55b303f").unwrap();
         check(
-            Bip84Public(pubkey, fingerprint, KeychainKind::External).build(),
+            Bip84Public(pubkey, fingerprint, KeychainKind::External).build(Network::Bitcoin),
             true,
             false,
             &[
@@ -713,7 +757,7 @@ mod test {
             ],
         );
         check(
-            Bip84Public(pubkey, fingerprint, KeychainKind::Internal).build(),
+            Bip84Public(pubkey, fingerprint, KeychainKind::Internal).build(Network::Bitcoin),
             true,
             false,
             &[

src/lib.rs

@@ -44,7 +44,7 @@
 //! interact with the bitcoin P2P network.
 //!
 //! ```toml
-//! bdk = "0.18.0"
+//! bdk = "0.20.0"
 //! ```
 //!
 //! # Examples

src/testutils/blockchain_tests.rs

@@ -372,6 +372,7 @@ macro_rules! bdk_blockchain_tests {
             use $crate::blockchain::Blockchain;
             use $crate::database::MemoryDatabase;
             use $crate::types::KeychainKind;
+            use $crate::wallet::AddressIndex;
             use $crate::{Wallet, FeeRate, SyncOptions};
             use $crate::testutils;
 
@@ -651,6 +652,60 @@ macro_rules! bdk_blockchain_tests {
                 assert_eq!(wallet.list_unspent().unwrap().len(), 1, "incorrect number of unspents");
             }
 
+            // Syncing wallet should not result in wallet address index to decrement.
+            // This is critical as we should always ensure to not reuse addresses.
+            #[test]
+            fn test_sync_address_index_should_not_decrement() {
+                let (wallet, blockchain, _descriptors, mut test_client) = init_single_sig();
+
+                const ADDRS_TO_FUND: u32 = 7;
+                const ADDRS_TO_IGNORE: u32 = 11;
+
+                let mut first_addr_index: u32 = 0;
+
+                (0..ADDRS_TO_FUND + ADDRS_TO_IGNORE).for_each(|i| {
+                    let new_addr = wallet.get_address(AddressIndex::New).unwrap();
+
+                    if i == 0 {
+                        first_addr_index = new_addr.index;
+                    }
+                    assert_eq!(new_addr.index, i+first_addr_index, "unexpected new address index (before sync)");
+
+                    if i < ADDRS_TO_FUND {
+                        test_client.receive(testutils! {
+                            @tx ((@addr new_addr.address) => 50_000)
+                        });
+                    }
+                });
+
+                wallet.sync(&blockchain, SyncOptions::default()).unwrap();
+
+                let new_addr = wallet.get_address(AddressIndex::New).unwrap();
+                assert_eq!(new_addr.index, ADDRS_TO_FUND+ADDRS_TO_IGNORE+first_addr_index, "unexpected new address index (after sync)");
+            }
+
+            // Even if user does not explicitly grab new addresses, the address index should
+            // increment after sync (if wallet has a balance).
+            #[test]
+            fn test_sync_address_index_should_increment() {
+                let (wallet, blockchain, descriptors, mut test_client) = init_single_sig();
+
+                const START_FUND: u32 = 4;
+                const END_FUND: u32 = 20;
+
+                // "secretly" fund wallet via given range
+                (START_FUND..END_FUND).for_each(|addr_index| {
+                    test_client.receive(testutils! {
+                        @tx ((@external descriptors, addr_index) => 50_000)
+                    });
+                });
+
+                wallet.sync(&blockchain, SyncOptions::default()).unwrap();
+
+                let address = wallet.get_address(AddressIndex::New).unwrap();
+                assert_eq!(address.index, END_FUND, "unexpected new address index (after sync)");
+            }
+
             /// Send two conflicting transactions to the same address twice in a row.
             /// The coins should only be received once!
             #[test]
@@ -1361,6 +1416,35 @@ macro_rules! bdk_blockchain_tests {
                 let finalized = wallet.sign(&mut psbt, Default::default()).unwrap();
                 assert_eq!(finalized, true);
             }
+
+            #[test]
+            fn test_get_block_hash() {
+                use bitcoincore_rpc::{ RpcApi };
+                use crate::blockchain::GetBlockHash;
+
+                // create wallet with init_wallet
+                let (_, blockchain, _descriptors, mut test_client) = init_single_sig();
+
+                let height = test_client.bitcoind.client.get_blockchain_info().unwrap().blocks as u64;
+                let best_hash = test_client.bitcoind.client.get_best_block_hash().unwrap();
+
+                // use get_block_hash to get best block hash and compare with best_hash above
+                let block_hash = blockchain.get_block_hash(height).unwrap();
+                assert_eq!(best_hash, block_hash);
+
+                // generate blocks to address
+                let node_addr = test_client.get_node_address(None);
+                test_client.generate(10, Some(node_addr));
+
+                let height = test_client.bitcoind.client.get_blockchain_info().unwrap().blocks as u64;
+                let best_hash = test_client.bitcoind.client.get_best_block_hash().unwrap();
+
+                let block_hash = blockchain.get_block_hash(height).unwrap();
+                assert_eq!(best_hash, block_hash);
+
+                // try to get hash for block that has not yet been created.
+                assert!(blockchain.get_block_hash(height + 1).is_err());
+            }
         }
     };
 

src/testutils/configurable_blockchain_tests.rs

@@ -0,0 +1,140 @@
+use bitcoin::Network;
+
+use crate::{
+    blockchain::ConfigurableBlockchain, database::MemoryDatabase, testutils, wallet::AddressIndex,
+    Wallet,
+};
+
+use super::blockchain_tests::TestClient;
+
+/// Trait for testing [`ConfigurableBlockchain`] implementations.
+pub trait ConfigurableBlockchainTester<B: ConfigurableBlockchain>: Sized {
+    /// Blockchain name for logging.
+    const BLOCKCHAIN_NAME: &'static str;
+
+    /// Generates a blockchain config with a given stop_gap.
+    ///
+    /// If this returns [`Option::None`], then the associated tests will not run.
+    fn config_with_stop_gap(
+        &self,
+        _test_client: &mut TestClient,
+        _stop_gap: usize,
+    ) -> Option<B::Config> {
+        None
+    }
+
+    /// Runs all avaliable tests.
+    fn run(&self) {
+        let test_client = &mut TestClient::default();
+
+        if self.config_with_stop_gap(test_client, 0).is_some() {
+            test_wallet_sync_with_stop_gaps(test_client, self);
+        } else {
+            println!(
+                "{}: Skipped tests requiring config_with_stop_gap.",
+                Self::BLOCKCHAIN_NAME
+            );
+        }
+    }
+}
+
+/// Test whether blockchain implementation syncs with expected behaviour given different `stop_gap`
+/// parameters.
+///
+/// For each test vector:
+/// * Fill wallet's derived addresses with balances (as specified by test vector).
+///    * [0..addrs_before]          => 1000sats for each address
+///    * [addrs_before..actual_gap] => empty addresses
+///    * [actual_gap..addrs_after]  => 1000sats for each address
+/// * Then, perform wallet sync and obtain wallet balance
+/// * Check balance is within expected range (we can compare `stop_gap` and `actual_gap` to
+///    determine this).
+fn test_wallet_sync_with_stop_gaps<T, B>(test_client: &mut TestClient, tester: &T)
+where
+    T: ConfigurableBlockchainTester<B>,
+    B: ConfigurableBlockchain,
+{
+    // Generates wallet descriptor
+    let descriptor_of_account = |account_index: usize| -> String {
+        format!("wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/{account_index}/*)")
+    };
+
+    // Amount (in satoshis) provided to a single address (which expects to have a balance)
+    const AMOUNT_PER_TX: u64 = 1000;
+
+    // [stop_gap, actual_gap, addrs_before, addrs_after]
+    //
+    // [0]     stop_gap: Passed to [`ElectrumBlockchainConfig`]
+    // [1]   actual_gap: Range size of address indexes without a balance
+    // [2] addrs_before: Range size of address indexes (before gap) which contains a balance
+    // [3]  addrs_after: Range size of address indexes (after gap) which contains a balance
+    let test_vectors: Vec<[u64; 4]> = vec![
+        [0, 0, 0, 5],
+        [0, 0, 5, 5],
+        [0, 1, 5, 5],
+        [0, 2, 5, 5],
+        [1, 0, 5, 5],
+        [1, 1, 5, 5],
+        [1, 2, 5, 5],
+        [2, 1, 5, 5],
+        [2, 2, 5, 5],
+        [2, 3, 5, 5],
+    ];
+
+    for (account_index, vector) in test_vectors.into_iter().enumerate() {
+        let [stop_gap, actual_gap, addrs_before, addrs_after] = vector;
+        let descriptor = descriptor_of_account(account_index);
+
+        let blockchain = B::from_config(
+            &tester
+                .config_with_stop_gap(test_client, stop_gap as _)
+                .unwrap(),
+        )
+        .unwrap();
+
+        let wallet =
+            Wallet::new(&descriptor, None, Network::Regtest, MemoryDatabase::new()).unwrap();
+
+        // fill server-side with txs to specified address indexes
+        // return the max balance of the wallet (also the actual balance)
+        let max_balance = (0..addrs_before)
+            .chain(addrs_before + actual_gap..addrs_before + actual_gap + addrs_after)
+            .fold(0_u64, |sum, i| {
+                let address = wallet.get_address(AddressIndex::Peek(i as _)).unwrap();
+                test_client.receive(testutils! {
+                    @tx ( (@addr address.address) => AMOUNT_PER_TX )
+                });
+                sum + AMOUNT_PER_TX
+            });
+
+        // minimum allowed balance of wallet (based on stop gap)
+        let min_balance = if actual_gap > stop_gap {
+            addrs_before * AMOUNT_PER_TX
+        } else {
+            max_balance
+        };
+
+        // perform wallet sync
+        wallet.sync(&blockchain, Default::default()).unwrap();
+
+        let wallet_balance = wallet.get_balance().unwrap();
+
+        let details = format!(
+            "test_vector: [stop_gap: {}, actual_gap: {}, addrs_before: {}, addrs_after: {}]",
+            stop_gap, actual_gap, addrs_before, addrs_after,
+        );
+        assert!(
+            wallet_balance <= max_balance,
+            "wallet balance is greater than received amount: {}",
+            details
+        );
+        assert!(
+            wallet_balance >= min_balance,
+            "wallet balance is smaller than expected: {}",
+            details
+        );
+
+        // generate block to confirm new transactions
+        test_client.generate(1, None);
+    }
+}

src/testutils/mod.rs

@@ -14,6 +14,10 @@
 #[cfg(feature = "test-blockchains")]
 pub mod blockchain_tests;
 
+#[cfg(test)]
+#[cfg(feature = "test-blockchains")]
+pub mod configurable_blockchain_tests;
+
 use bitcoin::{Address, Txid};
 
 #[derive(Clone, Debug)]

src/types.rs

@@ -202,8 +202,10 @@ pub struct TransactionDetails {
     pub txid: Txid,
 
     /// Received value (sats)
+    /// Sum of owned outputs of this transaction.
     pub received: u64,
     /// Sent value (sats)
+    /// Sum of owned inputs of this transaction.
     pub sent: u64,
     /// Fee value (sats) if available.
     /// The availability of the fee depends on the backend. It's never `None` with an Electrum

src/wallet/address_validator.rs

@@ -100,6 +100,7 @@ impl std::error::Error for AddressValidatorError {}
 /// validator will be propagated up to the original caller that triggered the address generation.
 ///
 /// For a usage example see [this module](crate::address_validator)'s documentation.
+#[deprecated = "AddressValidator was rarely used. Address validation can occur outside of BDK"]
 pub trait AddressValidator: Send + Sync + fmt::Debug {
     /// Validate or inspect an address
     fn validate(
@@ -120,6 +121,7 @@ mod test {
 
     #[derive(Debug)]
     struct TestValidator;
+    #[allow(deprecated)]
     impl AddressValidator for TestValidator {
         fn validate(
             &self,
@@ -135,6 +137,7 @@ mod test {
     #[should_panic(expected = "InvalidScript")]
     fn test_address_validator_external() {
         let (mut wallet, _, _) = get_funded_wallet(get_test_wpkh());
+        #[allow(deprecated)]
         wallet.add_address_validator(Arc::new(TestValidator));
 
         wallet.get_address(New).unwrap();
@@ -144,6 +147,7 @@ mod test {
     #[should_panic(expected = "InvalidScript")]
     fn test_address_validator_internal() {
         let (mut wallet, descriptors, _) = get_funded_wallet(get_test_wpkh());
+        #[allow(deprecated)]
         wallet.add_address_validator(Arc::new(TestValidator));
 
         let addr = crate::testutils!(@external descriptors, 10);

src/wallet/mod.rs

@@ -50,6 +50,7 @@ pub mod verify;
 
 pub use utils::IsDust;
 
+#[allow(deprecated)]
 use address_validator::AddressValidator;
 use coin_selection::DefaultCoinSelectionAlgorithm;
 use signer::{SignOptions, SignerOrdering, SignersContainer, TransactionSigner};
@@ -73,6 +74,7 @@ use crate::testutils;
 use crate::types::*;
 
 const CACHE_ADDR_BATCH_SIZE: u32 = 100;
+const COINBASE_MATURITY: u32 = 100;
 
 /// A Bitcoin wallet
 ///
@@ -93,6 +95,7 @@ pub struct Wallet<D> {
     signers: Arc<SignersContainer>,
     change_signers: Arc<SignersContainer>,
 
+    #[allow(deprecated)]
     address_validators: Vec<Arc<dyn AddressValidator>>,
 
     network: Network,
@@ -499,11 +502,17 @@ where
     /// Add an address validator
     ///
     /// See [the `address_validator` module](address_validator) for an example.
+    #[deprecated]
+    #[allow(deprecated)]
     pub fn add_address_validator(&mut self, validator: Arc<dyn AddressValidator>) {
         self.address_validators.push(validator);
     }
 
     /// Get the address validators
+    ///
+    /// See [the `address_validator` module](address_validator).
+    #[deprecated]
+    #[allow(deprecated)]
     pub fn get_address_validators(&self) -> &[Arc<dyn AddressValidator>] {
         &self.address_validators
     }
@@ -619,9 +628,27 @@ where
             _ => 1,
         };
 
+        // We use a match here instead of a map_or_else as it's way more readable :)
+        let current_height = match params.current_height {
+            // If they didn't tell us the current height, we assume it's the latest sync height.
+            None => self
+                .database()
+                .get_sync_time()?
+                .map(|sync_time| sync_time.block_time.height),
+            h => h,
+        };
+
         let lock_time = match params.locktime {
-            // No nLockTime, default to 0
-            None => requirements.timelock.unwrap_or(0),
+            // When no nLockTime is specified, we try to prevent fee sniping, if possible
+            None => {
+                // Fee sniping can be partially prevented by setting the timelock
+                // to current_height. If we don't know the current_height,
+                // we default to 0.
+                let fee_sniping_height = current_height.unwrap_or(0);
+                // We choose the biggest between the required nlocktime and the fee sniping
+                // height
+                std::cmp::max(requirements.timelock.unwrap_or(0), fee_sniping_height)
+            }
             // Specific nLockTime required and we have no constraints, so just set to that value
             Some(x) if requirements.timelock.is_none() => x,
             // Specific nLockTime required and it's compatible with the constraints
@@ -747,6 +774,7 @@ where
             params.drain_wallet,
             params.manually_selected_only,
             params.bumping_fee.is_some(), // we mandate confirmed transactions if we're bumping the fee
+            current_height,
         )?;
 
         let coin_selection = coin_selection.coin_select(
@@ -791,7 +819,14 @@ where
         let drain_val = (coin_selection.selected_amount() - outgoing).saturating_sub(fee_amount);
 
         if tx.output.is_empty() {
-            if params.drain_to.is_some() {
+            // Uh oh, our transaction has no outputs.
+            // We allow this when:
+            // - We have a drain_to address and the utxos we must spend (this happens,
+            // for example, when we RBF)
+            // - We have a drain_to address and drain_wallet set
+            // Otherwise, we don't know who we should send the funds to, and how much
+            // we should send!
+            if params.drain_to.is_some() && (params.drain_wallet || !params.utxos.is_empty()) {
                 if drain_val.is_dust(&drain_output.script_pubkey) {
                     return Err(Error::InsufficientFunds {
                         needed: drain_output.script_pubkey.dust_value().as_sat(),
@@ -872,8 +907,6 @@ where
     /// # Ok::<(), bdk::Error>(())
     /// ```
     // TODO: support for merging multiple transactions while bumping the fees
-    // TODO: option to force addition of an extra output? seems bad for privacy to update the
-    // change
     pub fn build_fee_bump(
         &self,
         txid: Txid,
@@ -1050,7 +1083,11 @@ where
         }
 
         // attempt to finalize
-        self.finalize_psbt(psbt, sign_options)
+        if sign_options.try_finalize {
+            self.finalize_psbt(psbt, sign_options)
+        } else {
+            Ok(false)
+        }
     }
 
     /// Return the spending policies for the wallet's descriptor
@@ -1161,6 +1198,9 @@ where
                             let psbt_input = &mut psbt.inputs[n];
                             psbt_input.final_script_sig = Some(tmp_input.script_sig);
                             psbt_input.final_script_witness = Some(tmp_input.witness);
+                            if sign_options.remove_partial_sigs {
+                                psbt_input.partial_sigs.clear();
+                            }
                         }
                         Err(e) => {
                             debug!("satisfy error {:?} for input {}", e, n);
@@ -1235,6 +1275,7 @@ where
         let script = derived_descriptor.script_pubkey();
 
         for validator in &self.address_validators {
+            #[allow(deprecated)]
             validator.validate(keychain, &hd_keypaths, &script)?;
         }
 
@@ -1317,6 +1358,7 @@ where
     /// Given the options returns the list of utxos that must be used to form the
     /// transaction and any further that may be used if needed.
     #[allow(clippy::type_complexity)]
+    #[allow(clippy::too_many_arguments)]
     fn preselect_utxos(
         &self,
         change_policy: tx_builder::ChangeSpendPolicy,
@@ -1325,6 +1367,7 @@ where
         must_use_all_available: bool,
         manual_only: bool,
         must_only_use_confirmed_tx: bool,
+        current_height: Option<u32>,
     ) -> Result<(Vec<WeightedUtxo>, Vec<WeightedUtxo>), Error> {
         //    must_spend <- manually selected utxos
         //    may_spend  <- all other available utxos
@@ -1343,23 +1386,44 @@ where
             return Ok((must_spend, vec![]));
         }
 
-        let satisfies_confirmed = match must_only_use_confirmed_tx {
-            true => {
-                let database = self.database.borrow();
-                may_spend
-                    .iter()
-                    .map(|u| {
-                        database
-                            .get_tx(&u.0.outpoint.txid, true)
-                            .map(|tx| match tx {
-                                None => false,
-                                Some(tx) => tx.confirmation_time.is_some(),
-                            })
+        let database = self.database.borrow();
+        let satisfies_confirmed = may_spend
+            .iter()
+            .map(|u| {
+                database
+                    .get_tx(&u.0.outpoint.txid, true)
+                    .map(|tx| match tx {
+                        // We don't have the tx in the db for some reason,
+                        // so we can't know for sure if it's mature or not.
+                        // We prefer not to spend it.
+                        None => false,
+                        Some(tx) => {
+                            // Whether the UTXO is mature and, if needed, confirmed
+                            let mut spendable = true;
+                            if must_only_use_confirmed_tx && tx.confirmation_time.is_none() {
+                                return false;
+                            }
+                            if tx
+                                .transaction
+                                .expect("We specifically ask for the transaction above")
+                                .is_coin_base()
+                            {
+                                if let Some(current_height) = current_height {
+                                    match &tx.confirmation_time {
+                                        Some(t) => {
+                                            // https://github.com/bitcoin/bitcoin/blob/c5e67be03bb06a5d7885c55db1f016fbf2333fe3/src/validation.cpp#L373-L375
+                                            spendable &= (current_height.saturating_sub(t.height))
+                                                >= COINBASE_MATURITY;
+                                        }
+                                        None => spendable = false,
+                                    }
+                                }
+                            }
+                            spendable
+                        }
                     })
-                    .collect::<Result<Vec<_>, _>>()?
-            }
-            false => vec![true; may_spend.len()],
-        };
+            })
+            .collect::<Result<Vec<_>, _>>()?;
 
         let mut i = 0;
         may_spend.retain(|u| {
@@ -1980,9 +2044,59 @@ pub(crate) mod test {
         builder.add_recipient(addr.script_pubkey(), 25_000);
         let (psbt, _) = builder.finish().unwrap();
 
+        // Since we never synced the wallet we don't have a last_sync_height
+        // we could use to try to prevent fee sniping. We default to 0.
         assert_eq!(psbt.unsigned_tx.lock_time, 0);
     }
 
+    #[test]
+    fn test_create_tx_fee_sniping_locktime_provided_height() {
+        let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
+        let addr = wallet.get_address(New).unwrap();
+        let mut builder = wallet.build_tx();
+        builder.add_recipient(addr.script_pubkey(), 25_000);
+        let sync_time = SyncTime {
+            block_time: BlockTime {
+                height: 24,
+                timestamp: 0,
+            },
+        };
+        wallet
+            .database
+            .borrow_mut()
+            .set_sync_time(sync_time)
+            .unwrap();
+        let current_height = 25;
+        builder.current_height(current_height);
+        let (psbt, _) = builder.finish().unwrap();
+
+        // current_height will override the last sync height
+        assert_eq!(psbt.unsigned_tx.lock_time, current_height);
+    }
+
+    #[test]
+    fn test_create_tx_fee_sniping_locktime_last_sync() {
+        let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
+        let addr = wallet.get_address(New).unwrap();
+        let mut builder = wallet.build_tx();
+        builder.add_recipient(addr.script_pubkey(), 25_000);
+        let sync_time = SyncTime {
+            block_time: BlockTime {
+                height: 25,
+                timestamp: 0,
+            },
+        };
+        wallet
+            .database
+            .borrow_mut()
+            .set_sync_time(sync_time.clone())
+            .unwrap();
+        let (psbt, _) = builder.finish().unwrap();
+
+        // If there's no current_height we're left with using the last sync height
+        assert_eq!(psbt.unsigned_tx.lock_time, sync_time.block_time.height);
+    }
+
     #[test]
     fn test_create_tx_default_locktime_cltv() {
         let (wallet, _, _) = get_funded_wallet(get_test_single_sig_cltv());
@@ -2001,9 +2115,13 @@ pub(crate) mod test {
         let mut builder = wallet.build_tx();
         builder
             .add_recipient(addr.script_pubkey(), 25_000)
+            .current_height(630_001)
             .nlocktime(630_000);
         let (psbt, _) = builder.finish().unwrap();
 
+        // When we explicitly specify a nlocktime
+        // we don't try any fee sniping prevention trick
+        // (we ignore the current_height)
         assert_eq!(psbt.unsigned_tx.lock_time, 630_000);
     }
 
@@ -2160,7 +2278,6 @@ pub(crate) mod test {
             .drain_to(drain_addr.script_pubkey())
             .drain_wallet();
         let (psbt, details) = builder.finish().unwrap();
-        dbg!(&psbt);
         let outputs = psbt.unsigned_tx.output;
 
         assert_eq!(outputs.len(), 2);
@@ -2176,6 +2293,40 @@ pub(crate) mod test {
         assert_eq!(drain_output.value, 30_000 - details.fee.unwrap_or(0));
     }
 
+    #[test]
+    fn test_create_tx_drain_to_and_utxos() {
+        let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
+        let addr = wallet.get_address(New).unwrap();
+        let utxos: Vec<_> = wallet
+            .get_available_utxos()
+            .unwrap()
+            .into_iter()
+            .map(|(u, _)| u.outpoint)
+            .collect();
+        let mut builder = wallet.build_tx();
+        builder
+            .drain_to(addr.script_pubkey())
+            .add_utxos(&utxos)
+            .unwrap();
+        let (psbt, details) = builder.finish().unwrap();
+
+        assert_eq!(psbt.unsigned_tx.output.len(), 1);
+        assert_eq!(
+            psbt.unsigned_tx.output[0].value,
+            50_000 - details.fee.unwrap_or(0)
+        );
+    }
+
+    #[test]
+    #[should_panic(expected = "NoRecipients")]
+    fn test_create_tx_drain_to_no_drain_wallet_no_utxos() {
+        let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
+        let drain_addr = wallet.get_address(New).unwrap();
+        let mut builder = wallet.build_tx();
+        builder.drain_to(drain_addr.script_pubkey());
+        builder.finish().unwrap();
+    }
+
     #[test]
     fn test_create_tx_default_fee_rate() {
         let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
@@ -3723,6 +3874,99 @@ pub(crate) mod test {
         assert_eq!(details.fee.unwrap_or(0), 250);
     }
 
+    #[test]
+    #[should_panic(expected = "InsufficientFunds")]
+    fn test_bump_fee_unconfirmed_inputs_only() {
+        // We try to bump the fee, but:
+        // - We can't reduce the change, as we have no change
+        // - All our UTXOs are unconfirmed
+        // So, we fail with "InsufficientFunds", as per RBF rule 2:
+        // The replacement transaction may only include an unconfirmed input
+        // if that input was included in one of the original transactions.
+        let (wallet, descriptors, _) = get_funded_wallet(get_test_wpkh());
+        let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
+        let mut builder = wallet.build_tx();
+        builder
+            .drain_wallet()
+            .drain_to(addr.script_pubkey())
+            .enable_rbf();
+        let (psbt, mut original_details) = builder.finish().unwrap();
+        // Now we receive one transaction with 0 confirmations. We won't be able to use that for
+        // fee bumping, as it's still unconfirmed!
+        crate::populate_test_db!(
+            wallet.database.borrow_mut(),
+            testutils! (@tx ( (@external descriptors, 0) => 25_000 ) (@confirmations 0)),
+            Some(100),
+        );
+        let mut tx = psbt.extract_tx();
+        let txid = tx.txid();
+        for txin in &mut tx.input {
+            txin.witness.push([0x00; 108]); // fake signature
+            wallet
+                .database
+                .borrow_mut()
+                .del_utxo(&txin.previous_output)
+                .unwrap();
+        }
+        original_details.transaction = Some(tx);
+        wallet
+            .database
+            .borrow_mut()
+            .set_tx(&original_details)
+            .unwrap();
+
+        let mut builder = wallet.build_fee_bump(txid).unwrap();
+        builder.fee_rate(FeeRate::from_sat_per_vb(25.0));
+        builder.finish().unwrap();
+    }
+
+    #[test]
+    fn test_bump_fee_unconfirmed_input() {
+        // We create a tx draining the wallet and spending one confirmed
+        // and one unconfirmed UTXO. We check that we can fee bump normally
+        // (BIP125 rule 2 only apply to newly added unconfirmed input, you can
+        // always fee bump with an unconfirmed input if it was included in the
+        // original transaction)
+        let (wallet, descriptors, _) = get_funded_wallet(get_test_wpkh());
+        let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
+        // We receive a tx with 0 confirmations, which will be used as an input
+        // in the drain tx.
+        crate::populate_test_db!(
+            wallet.database.borrow_mut(),
+            testutils! (@tx ( (@external descriptors, 0) => 25_000 ) (@confirmations 0)),
+            Some(100),
+        );
+        let mut builder = wallet.build_tx();
+        builder
+            .drain_wallet()
+            .drain_to(addr.script_pubkey())
+            .enable_rbf();
+        let (psbt, mut original_details) = builder.finish().unwrap();
+        let mut tx = psbt.extract_tx();
+        let txid = tx.txid();
+        for txin in &mut tx.input {
+            txin.witness.push([0x00; 108]); // fake signature
+            wallet
+                .database
+                .borrow_mut()
+                .del_utxo(&txin.previous_output)
+                .unwrap();
+        }
+        original_details.transaction = Some(tx);
+        wallet
+            .database
+            .borrow_mut()
+            .set_tx(&original_details)
+            .unwrap();
+
+        let mut builder = wallet.build_fee_bump(txid).unwrap();
+        builder
+            .fee_rate(FeeRate::from_sat_per_vb(15.0))
+            .allow_shrinking(addr.script_pubkey())
+            .unwrap();
+        builder.finish().unwrap();
+    }
+
     #[test]
     fn test_sign_single_xprv() {
         let (wallet, _, _) = get_funded_wallet("wpkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
@@ -3878,6 +4122,70 @@ pub(crate) mod test {
         )
     }
 
+    #[test]
+    fn test_remove_partial_sigs_after_finalize_sign_option() {
+        let (wallet, _, _) = get_funded_wallet("wpkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
+
+        for remove_partial_sigs in &[true, false] {
+            let addr = wallet.get_address(New).unwrap();
+            let mut builder = wallet.build_tx();
+            builder.drain_to(addr.script_pubkey()).drain_wallet();
+            let mut psbt = builder.finish().unwrap().0;
+
+            assert!(wallet
+                .sign(
+                    &mut psbt,
+                    SignOptions {
+                        remove_partial_sigs: *remove_partial_sigs,
+                        ..Default::default()
+                    },
+                )
+                .unwrap());
+
+            psbt.inputs.iter().for_each(|input| {
+                if *remove_partial_sigs {
+                    assert!(input.partial_sigs.is_empty())
+                } else {
+                    assert!(!input.partial_sigs.is_empty())
+                }
+            });
+        }
+    }
+
+    #[test]
+    fn test_try_finalize_sign_option() {
+        let (wallet, _, _) = get_funded_wallet("wpkh(tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)");
+
+        for try_finalize in &[true, false] {
+            let addr = wallet.get_address(New).unwrap();
+            let mut builder = wallet.build_tx();
+            builder.drain_to(addr.script_pubkey()).drain_wallet();
+            let mut psbt = builder.finish().unwrap().0;
+
+            let finalized = wallet
+                .sign(
+                    &mut psbt,
+                    SignOptions {
+                        try_finalize: *try_finalize,
+                        ..Default::default()
+                    },
+                )
+                .unwrap();
+
+            psbt.inputs.iter().for_each(|input| {
+                if *try_finalize {
+                    assert!(finalized);
+                    assert!(input.final_script_sig.is_some());
+                    assert!(input.final_script_witness.is_some());
+                } else {
+                    assert!(!finalized);
+                    assert!(input.final_script_sig.is_none());
+                    assert!(input.final_script_witness.is_none());
+                }
+            });
+        }
+    }
+
     #[test]
     fn test_sign_nonstandard_sighash() {
         let sighash = EcdsaSighashType::NonePlusAnyoneCanPay;
@@ -4158,7 +4466,7 @@ pub(crate) mod test {
             wallet.get_address(AddressIndex::New).unwrap(),
             AddressInfo {
                 index: 0,
-                address: Address::from_str("bcrt1qkmvk2nadgplmd57ztld8nf8v2yxkzmdvwtjf8s").unwrap(),
+                address: Address::from_str("bcrt1qrhgaqu0zvf5q2d0gwwz04w0dh0cuehhqvzpp4w").unwrap(),
                 keychain: KeychainKind::External,
             }
         );
@@ -4167,7 +4475,7 @@ pub(crate) mod test {
             wallet.get_internal_address(AddressIndex::New).unwrap(),
             AddressInfo {
                 index: 0,
-                address: Address::from_str("bcrt1qtrwtz00wxl69e5xex7amy4xzlxkaefg3gfdkxa").unwrap(),
+                address: Address::from_str("bcrt1q0ue3s5y935tw7v3gmnh36c5zzsaw4n9c9smq79").unwrap(),
                 keychain: KeychainKind::Internal,
             }
         );
@@ -4184,7 +4492,7 @@ pub(crate) mod test {
             wallet.get_internal_address(AddressIndex::New).unwrap(),
             AddressInfo {
                 index: 0,
-                address: Address::from_str("bcrt1qkmvk2nadgplmd57ztld8nf8v2yxkzmdvwtjf8s").unwrap(),
+                address: Address::from_str("bcrt1qrhgaqu0zvf5q2d0gwwz04w0dh0cuehhqvzpp4w").unwrap(),
                 keychain: KeychainKind::Internal,
             },
             "when there's no internal descriptor it should just use external"
@@ -4571,4 +4879,70 @@ pub(crate) mod test {
             "The signature should have been made with the right sighash"
         );
     }
+
+    #[test]
+    fn test_spend_coinbase() {
+        let descriptors = testutils!(@descriptors (get_test_wpkh()));
+        let wallet = Wallet::new(
+            &descriptors.0,
+            None,
+            Network::Regtest,
+            AnyDatabase::Memory(MemoryDatabase::new()),
+        )
+        .unwrap();
+
+        let confirmation_time = 5;
+
+        crate::populate_test_db!(
+            wallet.database.borrow_mut(),
+            testutils! (@tx ( (@external descriptors, 0) => 25_000 ) (@confirmations 1)),
+            Some(confirmation_time),
+            (@coinbase true)
+        );
+
+        let not_yet_mature_time = confirmation_time + COINBASE_MATURITY - 1;
+        let maturity_time = confirmation_time + COINBASE_MATURITY;
+
+        // The balance is nonzero, even if we can't spend anything
+        // FIXME: we should differentiate the balance between immature,
+        // trusted, untrusted_pending
+        // See https://github.com/bitcoindevkit/bdk/issues/238
+        let balance = wallet.get_balance().unwrap();
+        assert!(balance != 0);
+
+        // We try to create a transaction, only to notice that all
+        // our funds are unspendable
+        let addr = Address::from_str("2N1Ffz3WaNzbeLFBb51xyFMHYSEUXcbiSoX").unwrap();
+        let mut builder = wallet.build_tx();
+        builder
+            .add_recipient(addr.script_pubkey(), balance / 2)
+            .current_height(confirmation_time);
+        assert!(matches!(
+            builder.finish().unwrap_err(),
+            Error::InsufficientFunds {
+                needed: _,
+                available: 0
+            }
+        ));
+
+        // Still unspendable...
+        let mut builder = wallet.build_tx();
+        builder
+            .add_recipient(addr.script_pubkey(), balance / 2)
+            .current_height(not_yet_mature_time);
+        assert!(matches!(
+            builder.finish().unwrap_err(),
+            Error::InsufficientFunds {
+                needed: _,
+                available: 0
+            }
+        ));
+
+        // ...Now the coinbase is mature :)
+        let mut builder = wallet.build_tx();
+        builder
+            .add_recipient(addr.script_pubkey(), balance / 2)
+            .current_height(maturity_time);
+        builder.finish().unwrap();
+    }
 }

src/wallet/signer.rs

@@ -667,6 +667,16 @@ pub struct SignOptions {
     ///
     /// Defaults to `false` which will only allow signing using `SIGHASH_ALL`.
     pub allow_all_sighashes: bool,
+
+    /// Whether to remove partial_sigs from psbt inputs while finalizing psbt.
+    ///
+    /// Defaults to `true` which will remove partial_sigs after finalizing.
+    pub remove_partial_sigs: bool,
+
+    /// Whether to try finalizing psbt input after the inputs are signed.
+    ///
+    /// Defaults to `true` which will try fianlizing psbt after inputs are signed.
+    pub try_finalize: bool,
 }
 
 #[allow(clippy::derivable_impls)]
@@ -676,6 +686,8 @@ impl Default for SignOptions {
             trust_witness_utxo: false,
             assume_height: None,
             allow_all_sighashes: false,
+            remove_partial_sigs: true,
+            try_finalize: true,
         }
     }
 }

src/wallet/tx_builder.rs

@@ -147,6 +147,7 @@ pub(crate) struct TxParams {
     pub(crate) add_global_xpubs: bool,
     pub(crate) include_output_redeem_witness_script: bool,
     pub(crate) bumping_fee: Option<PreviousFee>,
+    pub(crate) current_height: Option<u32>,
 }
 
 #[derive(Clone, Copy, Debug)]
@@ -543,6 +544,22 @@ impl<'a, D: BatchDatabase, Cs: CoinSelectionAlgorithm<D>, Ctx: TxBuilderContext>
         self.params.rbf = Some(RbfValue::Value(nsequence));
         self
     }
+
+    /// Set the current blockchain height.
+    ///
+    /// This will be used to:
+    /// 1. Set the nLockTime for preventing fee sniping.
+    /// **Note**: This will be ignored if you manually specify a nlocktime using [`TxBuilder::nlocktime`].
+    /// 2. Decide whether coinbase outputs are mature or not. If the coinbase outputs are not
+    ///    mature at `current_height`, we ignore them in the coin selection.
+    ///    If you want to create a transaction that spends immature coinbase inputs, manually
+    ///    add them using [`TxBuilder::add_utxos`].
+    ///
+    /// In both cases, if you don't provide a current height, we use the last sync height.
+    pub fn current_height(&mut self, height: u32) -> &mut Self {
+        self.params.current_height = Some(height);
+        self
+    }
 }
 
 impl<'a, D: BatchDatabase, Cs: CoinSelectionAlgorithm<D>> TxBuilder<'a, D, Cs, CreateTx> {
@@ -574,6 +591,9 @@ impl<'a, D: BatchDatabase, Cs: CoinSelectionAlgorithm<D>> TxBuilder<'a, D, Cs, C
     /// difference is that it is valid to use `drain_to` without setting any ordinary recipients
     /// with [`add_recipient`] (but it is perfectly fine to add recipients as well).
     ///
+    /// If you choose not to set any recipients, you should either provide the utxos that the
+    /// transaction should spend via [`add_utxos`], or set [`drain_wallet`] to spend all of them.
+    ///
     /// When bumping the fees of a transaction made with this option, you probably want to
     /// use [`allow_shrinking`] to allow this output to be reduced to pay for the extra fees.
     ///
@@ -604,6 +624,7 @@ impl<'a, D: BatchDatabase, Cs: CoinSelectionAlgorithm<D>> TxBuilder<'a, D, Cs, C
     ///
     /// [`allow_shrinking`]: Self::allow_shrinking
     /// [`add_recipient`]: Self::add_recipient
+    /// [`add_utxos`]: Self::add_utxos
     /// [`drain_wallet`]: Self::drain_wallet
     pub fn drain_to(&mut self, script_pubkey: Script) -> &mut Self {
         self.params.drain_to = Some(script_pubkey);