CI linker failure after installing package

[ndimitrakas]

What happened?

After integrating the Google Mobile Ads SDK (v 12.4.0) via Swift Package Manager, my GitHub Actions build fails with linker errors for several new Swift 6 runtime libraries (swift_Builtin_float, swift_errno, swift_math, …) plus CoreAudioTypes.
Local builds on the same Xcode version succeed; the failure is reproducible only in CI. I've tried messing around with the versions of macos and xcode, however with no success. I am running Xcode 16.3 locally. Any guidance on a fix would be greatly appreciated.

Workflow Code

We use the following workflow to run our github actions:

name: PR Validation

on: [pull_request]

jobs: emulator_test: name: FirebaseServiceTests runs-on: macos-14 steps: - uses: actions/checkout@v4

  - uses: actions/setup-java@v1
    with:
      java-version: '11'

  - uses: maxim-lobanov/setup-xcode@v1
    with:
      xcode-version: '16.2'

  - name: Cache Firebase Emulators
    uses: actions/cache@v4
    with:
      path: ~/.cache/firebase/emulators
      key: ${{ runner.os }}-firebase-emulators-${{ github.sha }}
      restore-keys: |
        ${{ runner.os }}-firebase-emulators-

  - name: Install Firebase Emulator Suite
    run: npm install -g firebase-tools

  - name: Select Xcode
    run: sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

  - name: Install xcbeautify
    run: brew install xcbeautify

  - name: Create Config.xcconfig
    run: |
      echo "API_KEY = dummy_api_key_value" > /Users/runner/work/FitCheck/FitCheck/FitCheck/Config.xcconfig

  - name: Run unit tests with Firebase emulators
    working-directory: FirebaseEmulators
    run: firebase emulators:exec "set -o pipefail && xcodebuild -allowProvisioningUpdates -project ../FitCheck.xcodeproj -scheme FitCheck -configuration Debug -destination 'platform=iOS Simulator,name=iPhone 15' test | xcbeautify --renderer github-actions"`

Error Logs

[FitCheck] Linking FitCheck Warning: ld: Could not find or use auto-linked library 'swift_Builtin_float': library 'swift_Builtin_float' not found Warning: ld: Could not find or use auto-linked library 'swift_errno': library 'swift_errno' not found Warning: ld: Could not find or use auto-linked library 'swift_math': library 'swift_math' not found Warning: ld: Could not find or use auto-linked library 'swift_signal': library 'swift_signal' not found Warning: ld: Could not find or use auto-linked library 'swift_stdio': library 'swift_stdio' not found Warning: ld: Could not find or use auto-linked library 'swift_time': library 'swift_time' not found Warning: ld: Could not find or use auto-linked library 'swiftsys_time': library 'swiftsys_time' not found Warning: ld: Could not find or use auto-linked library 'swiftunistd': library 'swiftunistd' not found Warning: ld: Could not find or use auto-linked framework 'CoreAudioTypes': framework 'CoreAudioTypes' not found Error: Undefined symbols for architecture arm64 Error: "__swift_FORCE_LOAD_$_swift_Builtin_float", referenced from: Warning: __swift_FORCE_LOAD_$_swift_Builtin_float_$_GoogleMobileAds in GoogleMobileAds[arm64][409](GADMarketplaceKitSignals.o) Error: "__swift_FORCE_LOAD_$_swift_errno", referenced from: Warning: __swift_FORCE_LOAD_$_swift_errno_$_GoogleMobileAds in GoogleMobileAds[arm64][409](GADMarketplaceKitSignals.o) Error: "__swift_FORCE_LOAD_$_swift_math", referenced from: Warning: __swift_FORCE_LOAD_$_swift_math_$_GoogleMobileAds in GoogleMobileAds[arm64][409](GADMarketplaceKitSignals.o) Error: "__swift_FORCE_LOAD_$_swift_signal", referenced from: Warning: __swift_FORCE_LOAD_$_swift_signal_$_GoogleMobileAds in GoogleMobileAds[arm64][409](GADMarketplaceKitSignals.o) Error: "__swift_FORCE_LOAD_$_swift_stdio", referenced from: Warning: __swift_FORCE_LOAD_$_swift_stdio_$_GoogleMobileAds in GoogleMobileAds[arm64][409](GADMarketplaceKitSignals.o) Error: "__swift_FORCE_LOAD_$_swift_time", referenced from: Warning: __swift_FORCE_LOAD_$_swift_time_$_GoogleMobileAds in GoogleMobileAds[arm64][409](GADMarketplaceKitSignals.o) Error: "__swift_FORCE_LOAD_$_swiftsys_time", referenced from: Warning: __swift_FORCE_LOAD_$_swiftsys_time_$_GoogleMobileAds in GoogleMobileAds[arm64][409](GADMarketplaceKitSignals.o) Error: "__swift_FORCE_LOAD_$_swiftunistd", referenced from: Warning: __swift_FORCE_LOAD_$_swiftunistd_$_GoogleMobileAds in GoogleMobileAds[arm64][409](GADMarketplaceKitSignals.o) Error: ld: symbol(s) not found for architecture arm64 Error: clang: error: linker command failed with exit code 1 (use -v to see invocation) ⚠ Script exited unsuccessfully (code 65)