Xcode 27 Beta deprecation error

[elliot-garner]

Describe the bug

The LKObjCHelpers Objective-C target fails to compile against the iOS 27 SDK. Its public header references RPBroadcastSampleHandler (ReplayKit), which Apple deprecated in iOS 27:

// Sources/LKObjCHelpers/include/LKObjCHelpers.h
+ (void)finishBroadcastWithoutError:(RPBroadcastSampleHandler *)handler
    API_AVAILABLE(ios(10.0), macCatalyst(13.1), macos(11.0), tvos(10.0));

Because the module is built with -Werror in effect, the -Wdeprecated-declarations warning is promoted to an error and the precompiled module (.pcm) fails to emit, breaking the entire build of any project that depends on LiveKit:

LKObjCHelpers.h:6:38: error: 'RPBroadcastSampleHandler' is deprecated:
    first deprecated in iOS 27.0 - No longer supported
<unknown>:0: error: failed to emit precompiled module
    '.../LKObjCHelpers-XXXX.pcm' for module map '.../LKObjCHelpers.modulemap'

The header has no availability/deprecation guard or diagnostic pragma around this declaration. The header on the main branch (through release 2.14.1) is still unguarded, so the latest release is also affected.

SDK Version

client-sdk-swift 2.10.2

iOS/macOS Version

iOS 27.0 SDK.

Xcode Version

Xcode 27.0 beta, Build 27A5194q.

Steps to Reproduce

1. Add client-sdk-swift (any version up to 2.14.1) as a dependency.
2. Select Xcode 27.0 beta with the iOS 27 SDK.
3. Build for an iOS Simulator destination.
4. Build fails while generating the LKObjCHelpers precompiled module with the deprecation error above.

Logs

SwiftExplicitDependencyGeneratePcm arm64 .../LKObjCHelpers-XXXX.pcm
.../checkouts/client-sdk-swift/Sources/LKObjCHelpers/include/LKObjCHelpers.h:6:38:
    error: 'RPBroadcastSampleHandler' is deprecated: first deprecated in iOS 27.0 - No longer supported
<unknown>:0: error: failed to emit precompiled module
    '.../SwiftExplicitPrecompiledModules/LKObjCHelpers-XXXX.pcm'
    for module map '.../GeneratedModuleMaps-iphonesimulator/LKObjCHelpers.modulemap'

Failing frontend invocation: swift-frontend -emit-pcm -module-name LKObjCHelpers ... -sdk .../iPhoneSimulator27.0.sdk -target arm64-apple-ios17.6-simulator -clang-target arm64-apple-ios27.0-simulator -Xcc -Werror ... (the -Xcc -Werror is what promotes the deprecation to an error).

[pblazej]

I was unable to reproduce that (transitive dependency?), but pragmas should do the trick.

[pblazej]

There's a global PR for Xcode 27 beta ⤴️ should resolve all errors 🛑

[pblazej]

Reproduced the exact frontend invocation from the report (swift-frontend -emit-pcm … -target arm64-apple-ios17.6-simulator -clang-target arm64-apple-ios27.0-simulator -Xcc -Werror) against the iOS 27.0 SDK:

• Before: LKObjCHelpers.h:6:38: error: 'RPBroadcastSampleHandler' is deprecated: first deprecated in iOS 27.0 → 1 error generated, no .pcm.
• After (Fix Xcode 27 beta build errors #1038): the identical call emits LKObjCHelpers.pcm cleanly.

The fix wraps the declaration in #pragma clang diagnostic ignored "-Wdeprecated-declarations". The key to reproducing was -clang-target arm64-apple-ios27.0-simulator (Xcode 27 builds the clang PCM at the SDK version even though the Swift deployment target stays at 17.6), combined with -Xcc -Werror.