mantra-kmp/docs/ios-build.md

Bringing up the iOS target

What it takes to build and run Mantra on an iPhone, phased, following the route the Curated fork already walked. Every one of its findings is diagnosed and reproducible here, so the work is porting a known answer rather than re-discovering it.

The headline is that almost nothing is missing. The iosArm64 and iosSimulatorArm64 targets are already declared in composeApp/build.gradle.kts:36, gated behind OperatingSystem.current().isMacOsX the way everything in the composite chain is; composeApp/src/iosMain holds ten actual files that match jvmMain's ten one-for-one, so no expect is unimplemented; commonMain has no java.* or javax.* import anywhere; quartz 1.14.0 publishes iosArm64 and iosSimulatorArm64 klibs; and iosApp/ is byte-identical to Curated's apart from brand tokens and one icon file, Xcode build phase and all.

What stands in the way is five concrete defects, which Curated hit in the order a build hits them — configure, compile, link, connect, sign — and fixed in eight commits.

The eight commits, and what each one is here

Curated	what it did	how it lands here
94de86a3, cbf23640, 64b37447	three gitlink bumps of lightning-kmp-app, carrying a secp256k1-kmp build fix	the same three bumps, verbatim — Mantra is pinned at their exact parent
987df2c8	@ConstructedBy, @Throws(CancellationException), an unused import, TEAM_ID	the same, minus TEAM_ID, which is account-specific
aa9312f0	comma-free commonTest names, plus a disabled compiler phase	rewritten, not cherry-picked — see Phase 3
b9140c6a	the Darwin ktor engine	near-verbatim; the shape it assumes is the shape here
bd47c841	app icon and MARKETING_VERSION	needs Mantra artwork
a673c85e	versionName	a release decision, not a port

What is already done for you

The pin lines up exactly. Mantra records lightning-kmp-app at 84cc44c855e3d173e26016b807c449153a3af597. That is the parent of Curated's 94de86a3. The three bumps are therefore a straight walk along the same gitlinks — 84cc44c → 2dcd4fb → db15e59 → e0d2b82 — with no rebase and no divergence to reconcile.

The library's own iOS gating is already right. lightning-kmp-app/library declares iosArm64() and iosSimulatorArm64() under the same isMacOsX guard, and sets kotlin.native.enableKlibsCrossCompilation=true. Nothing in the outer build has to teach it about apple targets.

commonMain is clean, and the publish surface is small. One HttpClient { construction in the whole module (NostrSocketClientFactory.kt:10), no explicit Coil ImageLoader anywhere, six @Throws annotations on the publish path. That is the same shape Curated's fixes were written against, so Phases 2 and 4 are small and exact rather than a search.

The audit does not look at tests. docs/scripts/m3-audit.sh scans composeApp/src/commonMain/kotlin/press/mantra/compose/ui only, so Phase 3's sweep over test names cannot trip ./gradlew check.

What actually blocks it

Five things, independent of each other except for the order the build reveals them in:

1. The chain will not configure on a mac. secp256k1-kmp's .def declares staticLibraries for every target and the cinterop tool refuses to emit a klib while the archive is absent. Off a Linux host the Linux archives are never built, so the IDE sync and configuration fail with cinterop file ... does not exist. The fix — 9bcae25 in secp256k1-kmp, hardened by 8adf691 — stubs those archives under if (!currentOs.isLinux). Its commit subject says "linux cinterop", which reads backwards from here: it is the fix that makes the chain work on a mac, and it is a strict no-op on Linux.

2. Room cannot construct the database on native. MantraDatabaseConstructor already exists in commonMain, expect, @Suppressed and referenced by nothing. Without @ConstructedBy naming it, Room's KSP generates no actual, and on a target with no reflection there is no other way in.

3. Swift cannot see a cancellation as a cancellation. Six @Throws sites on the publish path name NostrPublishException and not kotlin.coroutines.cancellation.CancellationException, so a cancelled publish crosses the ObjC boundary as an unexpected throw.

4. The iOS link tasks fail, twice over. linkDebugTestIosArm64 is rejected by Kotlin/Native over backticked test names containing a comma (Name contains illegal characters: ','), and linkReleaseFrameworkIosArm64 crashes Kotlin 2.4.10's release backend inside StaticInitializersOptimization.

5. Nothing secure connects on a device. CIO has no TLS implementation on Kotlin/Native — every wss:// and https:// call dies at the handshake with TLS sessions are not supported on Native platform. The relay sockets and Coil's image fetcher both sit on a default-engine client.

Everything below is ordered by that list.

---

Phase 0 — bootstrap, and a recorded baseline

Nothing is changed in this phase. Its output is a green build to compare against, because four of the five defects above are invisible until a mac is in the loop and you do not want to be guessing afterwards which failure you introduced.

In this worktree, initialise the chain first. Four nested submodules — lightning-kmp-app → experimental/lightning-kmp → experimental/bitcoin-kmp → experimental/secp256k1-kmp (→ native/secp256k1) — are unpopulated, and gradle dies early and confusingly with Project with path ':library' not found:

git -c protocol.file.allow=always submodule update --init --recursive

protocol.file.allow=always is required: the recorded url for lightning-kmp-app is the main checkout's path, and git refuses file transport for submodules by default. The last level (native/secp256k1, fetched from GitHub) can stall for ten minutes or more; let the recursive call do what it can and finish that one level from the main checkout's copy. Trust git -C <level> rev-parse HEAD per level rather than git submodule status --recursive, which lies after a per-level url override.

Then record the baseline:

ANDROID_HOME=$HOME/Android/Sdk ./gradlew :composeApp:compileDebugKotlinAndroid :composeApp:jvmTest :lightning-kmp-app:library:jvmTest

Note the jvmTest count and that it is green. IdentitySwitchJvmTest's "last profile opened" case fails about one run in nine on a 5s DataStore timeout on a clean tree too — if you see exactly that, re-run before believing it.

Deliverable: no commit. A noted baseline.

---

Phase 1 — advance the library chain

The three gitlink bumps, kept as three commits so each one says what it carries. Walk the outer pin, and let the nested gitlinks come with it.

git -C lightning-kmp-app fetch https://github.com/kngako/lightning-kmp-app.git 'refs/heads/*:refs/remotes/github/*'
git -C lightning-kmp-app checkout --detach 2dcd4fbe1513421d100a4485583f167b1fdcd47c
git -c protocol.file.allow=always -C lightning-kmp-app submodule update --init --recursive
git add lightning-kmp-app && git commit

In a worktree the submodule's origin is the main checkout's copy, not GitHub, so git fetch origin shows nothing new — fetch the .gitmodules url directly, as above. Each bump moves experimental/lightning-kmp too, which moves bitcoin-kmp, which moves secp256k1-kmp, so re-run submodule update --init --recursive inside lightning-kmp-app after each checkout or the chain is left mid-walk.

The three, in order:

commit	pin	what it carries
1	2dcd4fb	secp256k1-kmp 9bcae25 — the stub archives that let the chain configure off Linux
2	db15e59	the same fix merged into the threshold branches, so the nested gitlinks name branch tips rather than side commits
3	e0d2b82	secp256k1-kmp 8adf691 — registers the stub task with tasks.register instead of the delegate provider, which Gradle 9 requires

Commits 2 and 3 look like bookkeeping and are not: without 3 the stub task is never registered under a name, and without 2 the pins sit on commits that were rebased away.

Verify, on Linux. The whole fix is behind if (!currentOs.isLinux), so Linux must be unchanged:

ANDROID_HOME=$HOME/Android/Sdk ./gradlew :composeApp:compileDebugKotlinAndroid :composeApp:jvmTest :lightning-kmp-app:library:jvmTest

Same test count, same green, as Phase 0. The library's own ~159 tests run inside the composite build and are the thing that proves the wiring still gives it what it expects.

Verify, on a mac. ./gradlew :composeApp:tasks configures at all, and :composeApp:compileKotlinIosArm64 resolves fr.acinq.phoenix:lightning-kmp-app. That is the phase's actual purpose.

Suggested message, commit 1: build: carry secp256k1-kmp's fix for configuring off a linux host — and say in the body that the upstream subject reads the other way round.

---

Phase 2 — declare the Room constructor and cancellation to Swift

Four small edits, one commit. All of it compiles on Linux.

@ConstructedBy. Add the import and the annotation above MantraDatabase.kt:369's @ColumnTypeConverters:

import androidx.room3.ConstructedBy
…
@ConstructedBy(MantraDatabaseConstructor::class)
@ColumnTypeConverters(MantraConverters::class)
abstract class MantraDatabase: RoomDatabase() {

The expect object it names already exists and needs no edit. This is the one change in the whole plan that also changes the JVM and Android builds: Room's KSP starts generating an actual for every target rather than none, so the annotation that unblocks iOS is the annotation most likely to move something underneath :composeApp:jvmTest. Run it and read the output rather than assuming.

Cancellation on the publish path. Add kotlin.coroutines.cancellation.CancellationException::class to the six existing @Throws, and give EventPublishTransport.publishEvent one it does not have:

• RelayPool.kt:289
• RelaysSocketManager.kt:103 and :118
• NostrPublisherRepository.kt:33, :55 and :66
• EventPublishTransport.kt:31 — new, naming NostrPublishException as well

Keep the fully-qualified style the surrounding annotations already use.

One unused import. import kotlin.native.Platform in Platform.ios.kt shadows the app's own Platform interface. Delete the line. Nothing on Linux compiles iosMain, so this one is carried on Curated's word and the compiler's, later.

Verify, on Linux: :composeApp:compileDebugKotlinAndroid :composeApp:jvmTest. On a mac: :composeApp:compileKotlinIosArm64.

feat(ios): declare the Room constructor and publish cancellation to swift

---

Phase 3 — unbreak the iOS link tasks

Two unrelated link failures, one commit, because they are the same symptom from the outside: ./gradlew :composeApp:linkDebugTestIosArm64 and :composeApp:linkReleaseFrameworkIosArm64 both fail.

The comma names — rewrite, do not cherry-pick

Curated's aa9312f0 touched 38 commonTest files. Ten of them do not exist here (GroupEventProposalTest, CuratedSchemaEventTest, CuratedEntryEventTest, CuratedSchemaTemplateTest, GroupCuratedEntryTest, GroupCuratedSchemaTest, GroupPostTest, CuratedSuggestionTest, MarmotRoomIdentityTest, MarmotPayloadBoundsTest, FrostSigningMembersTest) — they belong to the fork's curated-list and Marmot-v2 lines, neither of which Mantra has pulled. Meanwhile Mantra has test files Curated does not: ProjectEventTest, ChapterProposalSizeTest, UploadChaptersStateTest, UploadReviewTest, SubgroupLineageTest, MarkdownBlockTest, MarkdownProducerTest, ChapterTextTest.

So do the sweep over Mantra's own tree: 84 backticked fun names across 35 files in composeApp/src/commonTest. Every comma in every one of them is followed by exactly one space — verified, no exceptions — so the rewrite is total and unambiguous:

grep -rl 'fun `[^`]*,[^`]*`' composeApp/src/commonTest --include='*.kt' \
  | xargs perl -i -pe 's/(fun `[^`]*`)/($x=$1)=~s{, }{ }g; $x/ge'

Then read the diff. A name losing its comma loses a little of its rhythm and none of its meaning (read as its kind, tags and content → read as its kind tags and content); if any of the 84 reads badly afterwards, reword that one by hand rather than leaving a comma behind.

Leave jvmTest alone. It has 138 comma names and Kotlin/Native never compiles it. Curated left it alone for the same reason, and widening the sweep would put 138 cosmetic edits in a commit that is about a link failure.

The release backend crash

Append to composeApp/build.gradle.kts, after the kotlin { } block and before android { at line 161 — the same place Curated put it:

tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinNativeLink>().configureEach {
    if (name.startsWith("linkRelease")) {
        toolOptions.freeCompilerArgs.add("-Xdisable-phases=RemoveRedundantCallsToStaticInitializersPhase")
    }
}

With the comment Curated wrote, which is the valuable part: the pass is an LTO optimization, so only optimized links reach it (which is why the debug test binary links fine); it assumes every function in the call graph has at least one statement in its body; something in this module's graph arrives with an empty one; and disabling it costs the redundant initializer calls it would have removed and nothing else.

tasks.withType<KotlinNativeLink>() matches nothing on Linux, so this is inert there — but the class resolves from the KMP plugin's classpath on any host, so the script still has to compile. :composeApp:compileDebugKotlinAndroid proves that much.

Expect this one not to be the end of it. The crash is a property of the call graph, and Mantra's graph is a superset of Curated's — projects, chapter uploads, multi-parent subgroups, the markdown producer. The same phase may crash somewhere else, or a different phase may crash. Treat the stack trace as the instruction: disable the named phase, and write down why.

Verify, on a mac: :composeApp:linkDebugTestIosArm64 and :composeApp:linkReleaseFrameworkIosArm64. On Linux: :composeApp:compileDebugKotlinAndroid :composeApp:jvmTest — the renamed tests must still run, and the count must not move.

build(ios): unbreak the ios link tasks

---

Phase 4 — put every ktor client on Darwin

CIO has no TLS on Kotlin/Native. Pick the engine per platform instead of letting the classpath pick it.

Catalogue entry, beside ktor-client-cio in gradle/libs.versions.toml:82:

ktor-client-darwin = { module = "io.ktor:ktor-client-darwin", version.ref = "ktor" }

Dependency, inside the existing isMacOsX-gated iosMain.dependencies block at composeApp/build.gradle.kts:154. It goes inside the gate, which is why Linux resolution is untouched by this phase.

Three new files, an expect and two actuals, in press.mantra.compose.network:

• commonMain/.../PlatformHttpClientEngine.kt — internal expect fun platformHttpClientEngineFactory(): HttpClientEngineFactory<*>
• androidMain/.../PlatformHttpClientEngine.android.kt — = CIO
• jvmMain/.../PlatformHttpClientEngine.jvm.kt — = CIO
• iosMain/.../PlatformHttpClientEngine.ios.kt — = Darwin

Two call sites. defaultSocketsHttpClient becomes HttpClient(platformHttpClientEngineFactory()) { … }, keeping its WebSockets block as-is. And MantraApp gains the singleton Coil loader, because Coil's default ktor fetcher builds a bare HttpClient() and would fail on https:// images exactly as the sockets did:

private val imageHttpClient by lazy { HttpClient(platformHttpClientEngineFactory()) }

@Composable
fun MantraApp(…) {
    setSingletonImageLoaderFactory { context ->
        ImageLoader.Builder(context)
            .components { add(KtorNetworkFetcherFactory(httpClient = { imageHttpClient })) }
            .build()
    }

    MantraTheme { … }
}

setSingletonImageLoaderFactory goes above MantraTheme, at the top of the composable's body, so it is installed before the first AsyncImage composes. MantraApp is the only place both call sites are reachable from, and Mantra has no ImageLoader configuration today to reconcile with.

Verify, on Linux: :composeApp:compileDebugKotlinAndroid :composeApp:compileKotlinJvm :composeApp:jvmTest — the android and jvm actuals and both call sites compile here, which is most of the phase. On a mac: :composeApp:compileKotlinIosArm64, then the real test — a device or simulator that reaches a relay over wss:// and renders an avatar over https://.

fix(ios): build ktor clients on Darwin so wss/https work on a device

---

Phase 5 — signing, icon, version

Three things Curated's last two commits did that cannot be ported, only decided. Each needs an answer from you before it can be written.

TEAM_ID. iosApp/Configuration/Config.xcconfig has TEAM_ID= empty, and the bundle identifier is built from it (press.mantra.ios$(TEAM_ID)). Curated committed its development team id in the clear, which is normal for an xcconfig — a team id is not a secret — but it is their team id and signs builds to their account. Mantra needs its own, or an xcconfig that stays out of git.

The app icon. Curated replaced its single app-icon-1024.png with a 1024 light variant and a 1024 dark one, adding the luminosity: dark appearance to Contents.json and leaving the tinted slot filenameless so iOS derives it. Mantra's AppIcon.appiconset still holds one 1024 file and one entry. The structure ports; the artwork does not. Two 1024×1024 PNGs are needed.

MARKETING_VERSION. Mantra's xcconfig says 1.0 while android { versionName } says 0.1.2 — the two have simply never been reconciled because nothing shipped on iOS. Curated set both to the 0.1.x line. Pick one number for both; the mismatch is the bug, not either value.

Curated's a673c85e moved versionName from 0.1.2 to 0.1.1, which is a release-bookkeeping step on their tree and means nothing on this one. Do not port it.

feat(ios): the app icon, the signing team, and one version across both stores

---

Phase 6 — the part only a mac can find

Phases 1 to 4 fix everything Curated hit. They do not fix what Curated never had, and Mantra has pulled four lines of work the fork does not carry: projects, chapter uploads, multi-parent subgroups, and the markdown producer. None of it has ever been compiled for iosArm64.

So the honest shape of this phase is a loop, not a list:

./gradlew :composeApp:compileKotlinIosArm64
./gradlew :composeApp:linkDebugTestIosArm64
./gradlew :composeApp:iosSimulatorArm64Test
./gradlew :composeApp:linkReleaseFrameworkIosArm64

then Xcode, whose build phase already runs :composeApp:embedAndSignAppleFrameworkForXcode against the ComposeApp framework, deployment target 18.2.

Known places to look first, each a guess with a reason:

• FilePicker.ios.kt is the newest iosMain actual and the one behind chapter uploads. It exists, so it compiles in principle; whether UIDocumentPicker actually returns bytes on a device is untested anywhere.
• Anything reached only from the new screens — the StaticInitializers crash in Phase 3 is call-graph-shaped, and these four lines are what widened the graph.
• kotlinx.datetime and okio edges in the markdown and chapter paths, which are the usual source of a jvm-only overload that compiles everywhere but native.

Each fix found here is its own commit, in the voice of what broke rather than "ios fixes".

---

Phase 7 — write down what it cost

This document, revised from a plan into a record: which of the five defects behaved as predicted, what Phase 6 actually found, and which compiler phase is disabled with which stack trace behind it. Then revise its row in docs/README.md, which this document already carries, so it describes what happened rather than what was planned.

The -Xdisable-phases flag in particular needs a home in prose. It is a load- bearing workaround for an upstream compiler bug, it is invisible from the source, and the next person to bump Kotlin should be able to find out in one grep whether they can take it out again.

---

What to do if there is no mac

Phases 1 to 4 are worth landing anyway, and all four are verifiable on Linux for the half that Linux compiles:

phase	Linux-verifiable	needs a mac
1	the fix is if (!currentOs.isLinux), so "unchanged" is the whole check	that it configures at all
2	@ConstructedBy and all seven @Throws	the unused-import removal
3	the renamed tests still run; the build script still compiles	both link tasks
4	the expect, the android and jvm actuals, both call sites	the Darwin actual, and TLS actually working
5	nothing	nothing — it needs decisions, not a host

Phase 2's @ConstructedBy is the one with real Linux-side risk, since it changes what Room's KSP generates for every target. Land it on its own and read :composeApp:jvmTest carefully.