[SwiftBuild] Sample package that uses resources fails to build with `error: -fobjc-arc is not supported on platforms using the legacy runtime`

[bkhouri]

Is it reproducible with SwiftPM command-line tools: swift build, swift test, swift package etc?

• Confirmed reproduction steps with SwiftPM CLI. The description text must include reproduction steps with either of command-line SwiftPM commands, swift build, swift test, swift package etc.

Description

A sample package in SwiftPM fails to build with SwiftBuild build system with the following error with both debug and release build configurations.

error: -fobjc-arc is not supported on platforms using the legacy runtime

[2025-12-20T02:53:34.233Z]     error: CompileC C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.o C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\Sources\\MixedClangResource\\Foo.m normal x86_64 objective-c com.apple.compilers.llvm.clang.1_0.compiler failed with a nonzero exit code. Command line:     cd C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU

NOTE: This package was only supported on MacOS with the native build system. so it may be a moot point.

Expected behavior

the sample package was supported only on macOS, so we need to determine if this is something that should be supported with SwiftBuild on Windows.

Actual behavior

the build fails.

debug build configuration failure

[2025-12-20T02:53:34.233Z] × Test resourcesInMixedClangPackage(buildData:) recorded an issue with 1 argument buildData → BuildData(buildSystem: SPMBuildCore.BuildSystemProvider.Kind.swiftbuild, config: PackageModel.BuildConfiguration.debug) at ResourcesTests.swift:93:6: Caught error: terminated(1): C:\source\swiftpm\.test\x86_64-unknown-windows-msvc\debug\swift-build --package-path C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.Un5PjU\Resources_Simple --configuration debug --build-system swiftbuild --target MixedClangResource output:

[2025-12-20T02:53:34.233Z]     Building for debugging...

[2025-12-20T02:53:34.233Z]     [0/100] Computing dependencies

[2025-12-20T02:53:34.233Z]     [0/100] Provisioning 1 / 2

[2025-12-20T02:53:34.233Z]     [0/100] Constructing description

[2025-12-20T02:53:34.233Z]     [0/100] Pre-planning 1 / 66

[2025-12-20T02:53:34.233Z]     [0/100] Planning 1 / 66

[2025-12-20T02:53:34.233Z]     [0/100] Planning deferred tasks

[2025-12-20T02:53:34.233Z]     [0/100] Finalizing plan

[2025-12-20T02:53:34.233Z]     [0/100] Creating build graph

[2025-12-20T02:53:34.233Z]     [0/100] Constructing 1 / 123

[2025-12-20T02:53:34.233Z]     [0/100] Writing build description

[2025-12-20T02:53:34.233Z]     [0/100] Starting

[2025-12-20T02:53:34.233Z]     [20/100] 6 / 27

[2025-12-20T02:53:34.233Z]     [42/100] MixedClangResource 13 / 27

[2025-12-20T02:53:34.233Z]     [72/100] Resources_MixedClangResource 20 / 27

[2025-12-20T02:53:34.233Z]     [79/100] MixedClangResource 22 / 27

[2025-12-20T02:53:34.233Z]     [85/100] MixedClangResource 24 / 27

[2025-12-20T02:53:34.233Z]     Build description signature: a06e25aa5f7bd5d115ccdbc72771bb4e

[2025-12-20T02:53:34.233Z]     Build description path: C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.Un5PjU\Resources_Simple\.build\out\Intermediates.noindex\XCBuildData\a06e25aa5f7bd5d115ccdbc72771bb4e.xcbuilddata

[2025-12-20T02:53:34.233Z]     warning: no rule to process file 'C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.Un5PjU\Resources_Simple\.build\out\Intermediates.noindex\Resources.build\Debug-windows\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\DerivedSources\resource_bundle_accessor.m' of type 'sourcecode' for architecture 'x86_64'

[2025-12-20T02:53:34.233Z]     -fpascal-strings -O0 -DSWIFT_PACKAGE -DDEBUG=1 -fasm-blocks -fblocks "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Products\\Debug-windows\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\Sources\\MixedClangResource\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources-normal\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources" -DXcode -D_MT -D_DLL -Xclang --dependent-lib=msvcrt -gdwarf

[2025-12-20T02:53:34.233Z]     -fobjc-arc -fpascal-strings -O0 -DSWIFT_PACKAGE -DDEBUG=1 -DOBJC_OLD_DISPATCH_PROTOTYPES=1 -fasm-blocks -fblocks "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Products\\Debug-windows\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\Sources\\MixedClangResource\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources-normal\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources" -DXcode -D_MT -D_DLL -Xclang --dependent-lib=msvcrt -gdwarf

[2025-12-20T02:53:34.233Z]     -fpascal-strings -O0 -DSWIFT_PACKAGE -DDEBUG=1 -fasm-blocks -fblocks "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Products\\Debug-windows\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\Sources\\MixedClangResource\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources-normal\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources" -DXcode -D_MT -D_DLL -Xclang --dependent-lib=msvcrt -gdwarf

[2025-12-20T02:53:34.233Z]     -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG -fpascal-strings -O0 -DSWIFT_PACKAGE -DDEBUG=1 -fasm-blocks -fblocks "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Products\\Debug-windows\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\Sources\\MixedClangResource\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources-normal\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources" -DXcode -D_MT -D_DLL -Xclang --dependent-lib=msvcrt -gdwarf -gdwarf

[2025-12-20T02:53:34.233Z]     error: -fobjc-arc is not supported on platforms using the legacy runtime

[2025-12-20T02:53:34.233Z]     error: CompileC C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.o C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\Sources\\MixedClangResource\\Foo.m normal x86_64 objective-c com.apple.compilers.llvm.clang.1_0.compiler failed with a nonzero exit code. Command line:     cd C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU

[2025-12-20T02:53:34.233Z]         

[2025-12-20T02:53:34.233Z]         Using response file: C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.Un5PjU\Resources_Simple\.build\out\Intermediates.noindex\Resources.build\Debug-windows\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\Objects-normal\x86_64\e6072d4f65d7061329687fe24e3d63a7-common-args.resp

[2025-12-20T02:53:34.233Z]         

[2025-12-20T02:53:34.234Z]         C:\\Users\\ContainerAdministrator\\AppData\\Local\\Programs\\Swift\\Toolchains\\6.2.0+Asserts\\usr\\bin\\clang.exe -x objective-c -target x86_64-unknown-windows-msvc -fmessage-length\=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit\=0 -fno-color-diagnostics -Wno-trigraphs -Wno-missing-field-initializers -Wno-missing-prototypes -Wno-return-type -Wno-implicit-atomic-properties -Wno-objc-interface-ivars -Wno-arc-repeated-use-of-weak -Wno-missing-braces -Wparentheses -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wno-unused-variable -Wunused-value -Wno-empty-body -Wno-uninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-conversion -Wno-constant-conversion -Wno-int-conversion -Wno-bool-conversion -Wno-enum-conversion -Wno-float-conversion -Wno-non-literal-null-conversion -Wno-objc-literal-conversion -Wno-shorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-selector -Wno-strict-selector-match -Wno-undeclared-selector -Wno-deprecated-implementations -Wno-implicit-fallthrough -isysroot C:\\Users\\ContainerAdministrator\\AppData\\Local\\Programs\\Swift\\Platforms\\6.2.0\\Windows.platform\\Developer\\SDKs\\Windows.sdk -fstrict-aliasing -Wprotocol -Wdeprecated-declarations -Wno-sign-conversion -Wno-infinite-recursion -Wno-comma -Wno-block-capture-autoreleasing -Wno-strict-prototypes -Wno-semicolon-before-method-body @C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\e6072d4f65d7061329687fe24e3d63a7-common-args.resp -include C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\resource_bundle_accessor.h -MMD -MT dependencies -MF C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.d --serialize-diagnostics C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.dia -c C:\\Users\\Containtforms using the legacy runtime

[2025-12-20T02:53:34.234Z] 

[2025-12-20T02:53:34.234Z] error: CompileC C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.o C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\Sources\\MixedClangResource\\Foo.m normal x86_64 objective-c com.apple.compilers.llvm.clang.1_0.compiler failed with a nonzero exit code. Command line:     cd C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU

[2025-12-20T02:53:34.234Z]     

[2025-12-20T02:53:34.234Z]     Using response file: C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.Un5PjU\Resources_Simple\.build\out\Intermediates.noindex\Resources.build\Debug-windows\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\Objects-normal\x86_64\e6072d4f65d7061329687fe24e3d63a7-common-args.resp

[2025-12-20T02:53:34.234Z]     

[2025-12-20T02:53:34.234Z]     C:\\Users\\ContainerAdministrator\\AppData\\Local\\Programs\\Swift\\Toolchains\\6.2.0+Asserts\\usr\\bin\\clang.exe -x objective-c -target x86_64-unknown-windows-msvc -fmessage-length\=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit\=0 -fno-color-diagnostics -Wno-trigraphs -Wno-missing-field-initializers -Wno-missing-prototypes -Wno-return-type -Wno-implicit-atomic-properties -Wno-objc-interface-ivars -Wno-arc-repeated-use-of-weak -Wno-missing-braces -Wparentheses -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wno-unused-variable -Wunused-value -Wno-empty-body -Wno-uninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-conversion -Wno-constant-conversion -Wno-int-conversion -Wno-bool-conversion -Wno-enum-conversion -Wno-float-conversion -Wno-non-literal-null-conversion -Wno-objc-literal-conversion -Wno-shorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-selector -Wno-strict-selector-match -Wno-undeclared-selector -Wno-deprecated-implementations -Wno-implicit-fallthrough -isysroot C:\\Users\\ContainerAdministrator\\AppData\\Local\\Programs\\Swift\\Platforms\\6.2.0\\Windows.platform\\Developer\\SDKs\\Windows.sdk -fstrict-aliasing -Wprotocol -Wdeprecated-declarations -Wno-sign-conversion -Wno-infinite-recursion -Wno-comma -Wno-block-capture-autoreleasing -Wno-strict-prototypes -Wno-semicolon-before-method-body @C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\e6072d4f65d7061329687fe24e3d63a7-common-args.resp -include C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\resource_bundle_accessor.h -MMD -MT dependencies -MF C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.d --serialize-diagnostics C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.dia -c C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\Sources\\MixedClangResource\\Foo.m -o C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.Un5PjU\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Debug-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.o

[2025-12-20T02:53:34.234Z] error: Build failed

release build configuration test failure

[2025-12-20T02:53:34.234Z] × Test resourcesInMixedClangPackage(buildData:) recorded an issue with 1 argument buildData → BuildData(buildSystem: SPMBuildCore.BuildSystemProvider.Kind.swiftbuild, config: PackageModel.BuildConfiguration.release) at ResourcesTests.swift:93:6: Caught error: terminated(1): C:\source\swiftpm\.test\x86_64-unknown-windows-msvc\debug\swift-build --package-path C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.QoFrFL\Resources_Simple --configuration release --build-system swiftbuild --target MixedClangResource output:

[2025-12-20T02:53:34.234Z]     Building for production...

[2025-12-20T02:53:34.234Z]     [0/100] Computing dependencies

[2025-12-20T02:53:34.234Z]     [0/100] Provisioning 1 / 2

[2025-12-20T02:53:34.234Z]     [0/100] Constructing description

[2025-12-20T02:53:34.234Z]     [0/100] Pre-planning 1 / 66

[2025-12-20T02:53:34.234Z]     [0/100] Planning 1 / 66

[2025-12-20T02:53:34.234Z]     [0/100] Planning deferred tasks

[2025-12-20T02:53:34.234Z]     [0/100] Finalizing plan

[2025-12-20T02:53:34.234Z]     [0/100] Creating build graph

[2025-12-20T02:53:34.234Z]     [0/100] Constructing 1 / 123

[2025-12-20T02:53:34.234Z]     [0/100] Writing build description

[2025-12-20T02:53:34.234Z]     [0/100] Starting

[2025-12-20T02:53:34.234Z]     [25/100] Resources_MixedClangResource 7 / 27

[2025-12-20T02:53:34.234Z]     [42/100] MixedClangResource 13 / 27

[2025-12-20T02:53:34.234Z]     [72/100] Resources_MixedClangResource 20 / 27

[2025-12-20T02:53:34.234Z]     [82/100] MixedClangResource 23 / 27

[2025-12-20T02:53:34.234Z]     [93/100] MixedClangResource 26 / 27

[2025-12-20T02:53:34.234Z]     Build description signature: 05000342278680976ab99285f62d823f

[2025-12-20T02:53:34.234Z]     Build description path: C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.QoFrFL\Resources_Simple\.build\out\Intermediates.noindex\XCBuildData\05000342278680976ab99285f62d823f.xcbuilddata

[2025-12-20T02:53:34.234Z]     warning: no rule to process file 'C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.QoFrFL\Resources_Simple\.build\out\Intermediates.noindex\Resources.build\Release-windows\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\DerivedSources\resource_bundle_accessor.m' of type 'sourcecode' for architecture 'x86_64'

[2025-12-20T02:53:34.234Z]     -fpascal-strings -Os -DSWIFT_PACKAGE -fasm-blocks -fblocks "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Products\\Release-windows\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\Sources\\MixedClangResource\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources-normal\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources" -DXcode -D_MT -D_DLL -Xclang --dependent-lib=msvcrt -gdwarf -gdwarf

[2025-12-20T02:53:34.234Z]     -fpascal-strings -Os -DSWIFT_PACKAGE -fasm-blocks -fblocks "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Products\\Release-windows\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\Sources\\MixedClangResource\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources-normal\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources" -DXcode -D_MT -D_DLL -Xclang --dependent-lib=msvcrt -gdwarf

[2025-12-20T02:53:34.234Z]     -fobjc-arc -fpascal-strings -Os -DSWIFT_PACKAGE -DOBJC_OLD_DISPATCH_PROTOTYPES=1 -fasm-blocks -fblocks "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Products\\Release-windows\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\Sources\\MixedClangResource\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources-normal\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources" -DXcode -D_MT -D_DLL -Xclang --dependent-lib=msvcrt -gdwarf

[2025-12-20T02:53:34.234Z]     -fpascal-strings -Os -DSWIFT_PACKAGE -fasm-blocks -fblocks "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Products\\Release-windows\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\Sources\\MixedClangResource\\include" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources-normal\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\x86_64" "-IC:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources" -DXcode -D_MT -D_DLL -Xclang --dependent-lib=msvcrt -gdwarf

[2025-12-20T02:53:34.234Z]     C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.QoFrFL\Resources_Simple\.build\out\Products\Release-windows\Resources_MixedClangResource.bundle\foo.txt

[2025-12-20T02:53:34.234Z]     C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.QoFrFL\Resources_Simple\.build\out\Products\Release-windows\Resources_MixedClangResource.bundle\Info.plist

[2025-12-20T02:53:34.234Z]             2 file(s) copied.

[2025-12-20T02:53:34.234Z]     error: -fobjc-arc is not supported on platforms using the legacy runtime

[2025-12-20T02:53:34.234Z]     error: CompileC C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.o C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\Sources\\MixedClangResource\\Foo.m normal x86_64 objective-c com.apple.compilers.llvm.clang.1_0.compiler failed with a nonzero exit code. Command line:     cd C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL

[2025-12-20T02:53:34.234Z]         

[2025-12-20T02:53:34.234Z]         Using response file: C:\Users\ContainerAdministrator\AppData\Local\Temp\Resources_Simple.QoFrFL\Resources_Simple\.build\out\Intermediates.noindex\Resources.build\Release-windows\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\Objects-normal\x86_64\e6072d4f65d7061329687fe24e3d63a7-common-args.resp

[2025-12-20T02:53:34.234Z]         

[2025-12-20T02:53:35.599Z]         C:\\Users\\ContainerAdministrator\\AppData\\Local\\Programs\\Swift\\Toolchains\\6.2.0+Asserts\\usr\\bin\\clang.exe -x objective-c -target x86_64-unknown-windows-msvc -fmessage-length\=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit\=0 -fno-color-diagnostics -Wno-trigraphs -Wno-missing-field-initializers -Wno-missing-prototypes -Wno-return-type -Wno-implicit-atomic-properties -Wno-objc-interface-ivars -Wno-arc-repeated-use-of-weak -Wno-missing-braces -Wparentheses -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wno-unused-variable -Wunused-value -Wno-empty-body -Wno-uninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-conversion -Wno-constant-conversion -Wno-int-conversion -Wno-bool-conversion -Wno-enum-conversion -Wno-float-conversion -Wno-non-literal-null-conversion -Wno-objc-literal-conversion -Wno-shorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-selector -Wno-strict-selector-match -Wno-undeclared-selector -Wno-deprecated-implementations -Wno-implicit-fallthrough -isysroot C:\\Users\\ContainerAdministrator\\AppData\\Local\\Programs\\Swift\\Platforms\\6.2.0\\Windows.platform\\Developer\\SDKs\\Windows.sdk -fstrict-aliasing -Wprotocol -Wdeprecated-declarations -Wno-sign-conversion -Wno-infinite-recursion -Wno-comma -Wno-block-capture-autoreleasing -Wno-strict-prototypes -Wno-semicolon-before-method-body @C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\e6072d4f65d7061329687fe24e3d63a7-common-args.resp -include C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\resource_bundle_accessor.h -MMD -MT dependencies -MF C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.d --serialize-diagnostics C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simpct-selector-match -Wno-undeclared-selector -Wno-deprecated-implementations -Wno-implicit-fallthrough -isysroot C:\\Users\\ContainerAdministrator\\AppData\\Local\\Programs\\Swift\\Platforms\\6.2.0\\Windows.platform\\Developer\\SDKs\\Windows.sdk -fstrict-aliasing -Wprotocol -Wdeprecated-declarations -Wno-sign-conversion -Wno-infinite-recursion -Wno-comma -Wno-block-capture-autoreleasing -Wno-strict-prototypes -Wno-semicolon-before-method-body @C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\e6072d4f65d7061329687fe24e3d63a7-common-args.resp -include C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\DerivedSources\\resource_bundle_accessor.h -MMD -MT dependencies -MF C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.d --serialize-diagnostics C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.dia -c C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\Sources\\MixedClangResource\\Foo.m -o C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\Resources_Simple.QoFrFL\\Resources_Simple\\.build\\out\\Intermediates.noindex\\Resources.build\\Release-windows\\MixedClangResource49ba0716d3a0d11a9db19ea0e689db18.build\\Objects-normal\\x86_64\\Foo.o

[2025-12-20T02:53:35.599Z] error: Build failed

Steps to reproduce

option 1:

• Search for the issue in the SwiftPM tests
• remove the withKnownIssue in the test
• execute the tests

option2:

1. checkout SwiftPM repository
2. Run the following:

$ swift build --package-path ./Fixtures/Resources/Simple --target MixedClangResource --build-system swiftbuild --configuration debug

$ swift build --package-path ./Fixtures/Resources/Simple --target MixedClangResource --build-system swiftbuild --configuration release

Swift Package Manager version/commit hash

52f7c417c2949d9aadd950169c4ae3ab4a74f31c (branch main)

Swift & OS version (output of swift --version ; uname -a)

failed in CI running on Windows platform

[Viditgupta-official]

I can reproduce this on macOS using the SwiftBuild backend by targeting Windows.

The failure appears to come from -fobjc-arc being passed when building a resource-using target, which should be an Apple-only flag.

Before attempting a fix: can you confirm whether SwiftBuild is expected to support resource-based sample packages on Windows, or whether this configuration is intentionally unsupported?

Happy to investigate a fix or add coverage once intent is confirmed.

[plemarquand]

Possibly fixed by swiftlang/swift-build#918 ?

[Viditgupta-official]

I checked swiftlang/swift-build#918 — it removes -fobjc-arc from linker invocations, which helps, but the failure here still seems to come from -fobjc-arc being applied during compilation when targeting Windows, where ARC isn’t supported.

So it looks like the underlying question is whether SwiftBuild should avoid Objective-C / ARC flags on non-Darwin platforms, or treat this sample as macOS-only.