C++ Interop doesn't find headers when building with swiftbuild #887
Description
I have a swift artifact bundle using the new static library dependencies. I depend on this target in multiple other targets (both C++ and Swift).
The header structure looks like this:
libpulsar.artifactbundle |include |pulsar |Authentication.h |.. |libpulsar.modulemap Inside the modulemap the definition looks like this:
module CxxPulsar { header "pulsar/Authentication.h" export * } and the info.json like this:
{ "schemaVersion": "1.0", "artifacts": { "CxxPulsar": { "type": "staticLibrary", "version": "3.7.2", "variants": [ { "path": "dist/macos/libpulsarwithdeps.a", "supportedTriples": [ "arm64-apple-macosx" ], "staticLibraryMetadata": { "headerPaths": [ "include" ], "moduleMapPath": "include/libpulsar.modulemap" } } ] } } }Now, in my other C++ Target (self written) which depends on the artifactbundle, I have an #include <pulsar/Authentication.h> statement. With the legacy build system this compiles without issues, but when using swift build --build-system swiftbuild I get the following, slightly verbose error:
swift build --build-system swiftbuild Fetching https://github.com/apple/swift-log.git from cache Fetched https://github.com/apple/swift-log.git from cache (0.77s) Computing version for https://github.com/apple/swift-log.git Computed https://github.com/apple/swift-log.git at 1.6.4 (0.82s) Creating working copy for https://github.com/apple/swift-log.git Working copy of https://github.com/apple/swift-log.git resolved at 1.6.4 Building for debugging... warning: argument unused during compilation: '-fmodules-cache-path=/Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/ModuleCache.noindex' error: /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/Sources/Bridge/lib/ListenerShim.cpp:2:10 'pulsar/Authentication.h' file not found error: CompileC /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/ListenerShim.o /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/Sources/Bridge/lib/ListenerShim.cpp normal arm64 c++ com.apple.compilers.llvm.clang.1_0.compiler failed with a nonzero exit code. Command line: cd /Users/username/Developer/Swift/Pulsar Using response file: /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/82b82416624d2658e5098eb0a28c15c5-common-args.resp /Users/username/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-10-17-a.xctoolchain/usr/bin/clang -x c++ -target arm64-apple-macos26.0 -fmessage-length\=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit\=0 -fno-color-diagnostics -fmodules-prune-interval\=86400 -fmodules-prune-after\=345600 -fbuild-session-file\=/Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/ModuleCache.noindex/Session.modulevalidation -fmodules-validate-once-per-build-session -Wnon-modular-include-in-framework-module -Werror\=non-modular-include-in-framework-module -Wno-trigraphs -Wno-missing-field-initializers -Wno-missing-prototypes -Wno-return-type -Wno-non-virtual-dtor -Wno-overloaded-virtual -Wno-exit-time-destructors -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 -Wshorten-64-to-32 -Wno-newline-eof -Wno-c++11-extensions -Wno-implicit-fallthrough -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX26.0.sdk -fstrict-aliasing -Wdeprecated-declarations -Winvalid-offsetof -Wno-sign-conversion -Wno-infinite-recursion -Wno-move -Wno-comma -Wno-block-capture-autoreleasing -Wno-strict-prototypes -Wno-range-loop-analysis -Wno-semicolon-before-method-body -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk @/Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/82b82416624d2658e5098eb0a28c15c5-common-args.resp -MMD -MT dependencies -MF /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/ListenerShim.d --serialize-diagnostics /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/ListenerShim.dia -c /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/Sources/Bridge/lib/ListenerShim.cpp -o /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/ListenerShim.o error: CompileC /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/LoggerShim.o /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/Sources/Bridge/lib/LoggerShim.cpp normal arm64 c++ com.apple.compilers.llvm.clang.1_0.compiler failed with a nonzero exit code. Command line: cd /Users/username/Developer/Swift/Pulsar Using response file: /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/82b82416624d2658e5098eb0a28c15c5-common-args.resp /Users/username/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-10-17-a.xctoolchain/usr/bin/clang -x c++ -target arm64-apple-macos26.0 -fmessage-length\=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit\=0 -fno-color-diagnostics -fmodules-prune-interval\=86400 -fmodules-prune-after\=345600 -fbuild-session-file\=/Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/ModuleCache.noindex/Session.modulevalidation -fmodules-validate-once-per-build-session -Wnon-modular-include-in-framework-module -Werror\=non-modular-include-in-framework-module -Wno-trigraphs -Wno-missing-field-initializers -Wno-missing-prototypes -Wno-return-type -Wno-non-virtual-dtor -Wno-overloaded-virtual -Wno-exit-time-destructors -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 -Wshorten-64-to-32 -Wno-newline-eof -Wno-c++11-extensions -Wno-implicit-fallthrough -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX26.0.sdk -fstrict-aliasing -Wdeprecated-declarations -Winvalid-offsetof -Wno-sign-conversion -Wno-infinite-recursion -Wno-move -Wno-comma -Wno-block-capture-autoreleasing -Wno-strict-prototypes -Wno-range-loop-analysis -Wno-semicolon-before-method-body -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk @/Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/82b82416624d2658e5098eb0a28c15c5-common-args.resp -MMD -MT dependencies -MF /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/LoggerShim.d --serialize-diagnostics /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/LoggerShim.dia -c /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/Sources/Bridge/lib/LoggerShim.cpp -o /Users/username/Developer/Swift/Pulsar/pulsar-client-swift/.build/arm64-apple-macosx/Intermediates.noindex/pulsar-client-swift.build/Debug/Bridge.build/Objects-normal/arm64/LoggerShim.o error: Build failed While I'm not a C++ expert and maybe that's expected behavior and the legacy build system did it wrong, it's anyway a breaking change.