Non-existent Directory in Linker Path with rules_swift_package_manager

[bc-lee]

I'm encountering an issue while using rules_swift_package_manager to import third-party Swift package dependencies into my project. The linker path includes a non-existent directory, -LNone.

While this currently doesn't cause linker errors, it's concerning to have a non-existent path in the linker configuration. Additionally, None is a reserved keyword in both Python and Starlark(Bazel's build language), which could potentially lead to confusion.

I made a demo repository that demonstrates three different build methods:

1. SPM: Uses swift run for building.
2. Bazel with rules_swift_package_manager: Use CC=clang bazel build //Sources:test-bazel-swift-atomics
3. Bazel with Manual BUILD File: Use CC=clang bazel build //Sources:test-bazel-swift-atomics-alt

For easier reproduction, a GitHub action running the build command has been included. You can access the build log here: link to build log

The following snippet displays the linker command generated by Bazel with rules_swift_package_manager:

"/home/runner/work/test-bazel-swift-atomics/test-bazel-swift-atomics/swift/usr/bin/ld.lld" -pie --hash-style=gnu --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o bazel-out/k8-fastbuild/bin/Sources/test-bazel-swift-atomics /lib/x86_64-linux-gnu/Scrt1.o /lib/x86_64-linux-gnu/crti.o /usr/lib/gcc/x86_64-linux-gnu/14/crtbeginS.o -LNone -L/home/runner/work/test-bazel-swift-atomics/test-bazel-swift-atomics/swift/usr/lib/swift/linux -L/usr/lib/gcc/x86_64-linux-gnu/14 -L/usr/lib/gcc/x86_64-linux-gnu/14/../../../../lib64 -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/lib/../lib64 -L/lib -L/usr/lib -S -no-as-needed -z relro -z now bazel-out/k8-fastbuild/bin/Sources/test-bazel-swift-atomics_objs/main.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Conformances/OptionalRawRepresentable.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Conformances/RawRepresentable.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Conformances/autogenerated/AtomicBool.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Conformances/autogenerated/IntegerConformances.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Conformances/autogenerated/PointerConformances.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Primitives/autogenerated/Primitives.native.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Primitives/autogenerated/Primitives.shims.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Protocols/AtomicInteger.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Protocols/AtomicOptionalWrappable.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Protocols/AtomicReference.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Protocols/AtomicStorage.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Protocols/AtomicValue.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Types/AtomicMemoryOrderings.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Types/DoubleWord.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Types/ManagedAtomic.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Types/ManagedAtomicLazyReference.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Types/UnsafeAtomic.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Types/UnsafeAtomicLazyReference.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Types/autogenerated/IntegerOperations.swift.o bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.rspm_objs/Sources/Atomics/Unmanaged__SPACE__extensions.swift.o --start-lib bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/_objs/_AtomicsShims.rspm/_AtomicsShims.pic.o --end-lib bazel-out/k8-fastbuild/bin/external/rules_swift_package_manager~~swift_deps~swiftpkg_swift_atomics/Atomics.modulewrap.o -lswiftSwiftOnoneSupport -lswiftCore -lswift_Concurrency -lswift_StringProcessing -lswift_RegexParser -z nostart-stop-gc bazel-out/k8-fastbuild/bin/Sources/Sources_test_bazel_swift_atomics.modulewrap.o -lswiftSwiftOnoneSupport -lswiftCore -lswift_Concurrency -lswift_StringProcessing -lswift_RegexParser -lBlocksRuntime -ldispatch -lswiftDispatch -z nostart-stop-gc -rpath /home/runner/work/test-bazel-swift-atomics/test-bazel-swift-atomics/swift/usr/lib/swift/linux -lm -lstdc++ -lrt -ldl /home/runner/work/test-bazel-swift-atomics/test-bazel-swift-atomics/swift/usr/lib/swift/linux/x86_64/swiftrt.o --push-state -as-needed -lstdc++ --pop-state --push-state -as-needed -lm --pop-state -lgcc -lgcc_eh -lc -lgcc -lgcc_eh /usr/lib/gcc/x86_64-linux-gnu/14/crtendS.o /lib/x86_64-linux-gnu/crtn.o

As you can see, the -LNone flag is present in the linker path.