swift-foundation fails to build for Android with 4/1 nightly toolchain

[jmschonfeld]

Description

After the 4/1 nightly toolchain became available, swift-foundation is failing to build in CI

Reproduction

See CI run at https://github.com/swiftlang/swift-foundation/actions/runs/23912627888/job/69738273903?pr=1871

/usr/local/lib/android/sdk/ndk/29.0.14206865/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/include/c++/v1/cstdlib:93:5: error: <cstdlib> tried including <stdlib.h> but didn't find libc++'s <stdlib.h> header.           This usually means that your header search paths are not configured properly.           The header search paths should contain the C++ Standard Library headers before           any C Standard Library, and you are probably using compiler flags that make that           not be the case.
   93 | #   error <cstdlib> tried including <stdlib.h> but didn't find libc++'s <stdlib.h> header. \
      |     ^

Expected behavior

Build succeeds like normal

Environment

Swift version 6.4-dev (LLVM b8889af02f47cf7, Swift cf7481b)

Additional information

No response

[jmschonfeld]

Starting on the swift repo in case this is an Android SDK bug. cc @finagolfin in case you have any ideas. This does not reproduce with the 3/16 toolchain

[jmschonfeld]

This may be caused by the new build system, I don't repro when using --build-system native cc @owenv

[finagolfin]

Yep, that is the reason. Another strange bug I notice with the new SwiftPM swift-build backend is that it ignores the NDK 27d we specified and uses NDK 29 instead. I suggest we revert the swift-foundation CI manually to llbuild for now, because AFAIK none of the @swiftlang/android-workgroup has tried swift-build for Android yet, and once we get that working, we can make this swift-build transition later, okay, @jakepetroules?

[finagolfin]

Btw, @jmschonfeld, should we update the 6.3 CI for swift-foundation to also build all these against the 6.3 releases? Otherwise, that branch is currently only being built against the last month-old 6.3 snapshot.

[jmschonfeld]

I don't think so - we want the release/6.3 branch of swift-foundation to continue building against whatever nightly snapshots are produced from the release/6.3 compiler. We need to make sure that swift-foundation builds against whatever compiler/stdlib changes land in the corresponding 6.3.x releases, not just 6.3. I think the real problem here is that we haven't had a 6.3 snapshot in a month, the solution here is to resolve whatever is preventing that so the 6.3 snapshots aren't so old

[finagolfin]

Also, the swift-build switch probably broke your wasm CI too, so you'll want to go back to llbuild there too, cc @kateinoigakukun.

We need to make sure that swift-foundation builds against whatever compiler/stdlib changes land in the corresponding 6.3.x releases, not just 6.3.

Yep, I believe that's what adding 6.3 in that line from the CI config that I linked does, it just installs the latest 6.3 patch release.

I think the real problem here is that we haven't had a 6.3 snapshot in a month, the solution here is to resolve whatever is preventing that so the 6.3 snapshots aren't so old

In the past, the release branch snapshots are quickly phased out once the first release is tagged, so adding 6.3 there would make sure both are covered.

[kateinoigakukun]

The wasm CI issue is tracked by #88283

[jakepetroules]

Another strange bug I notice with the new SwiftPM swift-build backend is that it ignores the NDK 27d we specified and uses NDK 29 instead.

@finagolfin Can you please provide more specific details? Do you have a link to a build log? How are you specifying the NDK version for SwiftPM to pick up?

[jakepetroules]

@finagolfin Are you referring to the swiftlang GitHub Actions workflows? If so, I think you might just need to merge swiftlang/github-workflows#246 to get it to pick up the right NDK.

[finagolfin]

Can you please provide more specific details? Do you have a link to a build log?

I am just looking at the CI log that was linked in the OP above:

setup-android-sdk.sh: success: ndk-sysroot linked to Android NDK at /usr/local/lib/android/sdk/ndk/27.3.13750724/toolchains/llvm/prebuilt
/home/runner/work/swift-foundation/swift-foundation
** Running Swift build with Android Swift SDK
** Running: swift build --swift-sdk aarch64-unknown-linux-android28  
Fetching https://github.com/apple/swift-foundation-icu
[1/4676] Fetching swift-foundation-icu
Fetched https://github.com/apple/swift-foundation-icu from cache (7.83s)
Fetching https://github.com/swiftlang/swift-syntax
[1/74938] Fetching swift-syntax
Fetched https://github.com/swiftlang/swift-syntax from cache (4.36s)
Fetching https://github.com/apple/swift-collections
[1/23346] Fetching swift-collections
Fetched https://github.com/apple/swift-collections from cache (1.18s)
Computing version for https://github.com/apple/swift-collections
Computed https://github.com/apple/swift-collections at 1.4.1 (1.59s)
Creating working copy for https://github.com/apple/swift-foundation-icu
Working copy of https://github.com/apple/swift-foundation-icu resolved at main (a92f6ae)
Creating working copy for https://github.com/swiftlang/swift-syntax
Working copy of https://github.com/swiftlang/swift-syntax resolved at main (e9b5143)
Creating working copy for https://github.com/apple/swift-collections
Working copy of https://github.com/apple/swift-collections resolved at 1.4.1
Building for debugging...
Computing dependencies
Constructing description
Pre-planning 1 / 1033
Planning 806 / 1033
Planning deferred tasks
Constructing 597 / 2716
Starting
[21/100] swift-foundation_FoundationEssentialsTests 194 / 893
[21/100] _FoundationICU 197 / 893
In file included from /home/runner/work/swift-foundation/swift-foundation/.build/checkouts/swift-foundation-icu/icuSources/i18n/ztrans.cpp:22:
In file included from /home/runner/work/swift-foundation/swift-foundation/.build/checkouts/swift-foundation-icu/icuSources/common/cmemory.h:33:
In file included from /home/runner/work/swift-foundation/swift-foundation/.build/checkouts/swift-foundation-icu/icuSources/include/_foundation_unicode/localpointer.h:45:
In file included from /usr/local/lib/android/sdk/ndk/29.0.14206865/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/include/c++/v1/memory:947:

Note how the first line links against NDK 27d, but the last line uses headers from NDK 29.

How are you specifying the NDK version for SwiftPM to pick up?

Ideally, you'd set it using the swift sdk configure --sdk-root-path flag in SwiftPM, but since that command currently is not wired up to the build at all, swiftlang/swift-package-manager#8958, such a config change is ignored. We work around that SwiftPM bug by invoking an extra setup script that we ship in the Android SDK, which symlinks the NDK sysroot into the installed bundle then uses that from the bundle JSON config.

I am guessing you are overriding that in swift-build by checking some Android env variables, which we already argued is a bad idea when done in swift-driver, swiftlang/swift-driver#1879.

Are you referring to the swiftlang GitHub Actions workflows?

Yes, that is what the swift-foundation CI uses.

I think you might just need to merge swiftlang/github-workflows#246 to get it to pick up the right NDK.

No, that sets ANDROID_NDK_ROOT again, which is set to 27d also on the GitHub runners. Most likely you are checking the ANDROID_NDK_LATEST_HOME env var somewhere, which I think is a bad idea.