Can't compile with dependency with unsafe flags for different platform.

[nekrich]

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

Right now, swiftlang/swift-markdown has introduced an unsafe flag for the Windows platform.

I'm trying to build my package that depends on swift-format (which depends on swift-markdown) on macOS/Linux platforms, but neither swift build nor swift test succeeds.

I'm getting an error: 'swift-format': the target 'Markdown' in product 'Markdown' contains unsafe build flags on the macOS platform.

But unsafe flag is only for windows platform.

Linking a corresponding issue in swift-markdown: #239 .

I see three options for fixing this issue:

1. At least allow linking with dependencies that don't have unsafe flags for the current platform.
2. Have a flag to turn off the unsafe flags check. For folks who know what they are doing.
3. Ideally, Remove the unsafe flags check swift-package-manager#8876 completely.

Expected behavior

The swift test, swift build commands do the job and don't fail.

Actual behavior

1. An error: 'swift-format': the target 'Markdown' in product 'Markdown' contains unsafe build flags is thrown.
2. Package doesn't compile.

Steps to reproduce

1. Create a package that depends on the swift-markdown 0.7.0.
2. Build it on macOS/Linux platform.
3. You've got an error.

Swift Package Manager version/commit hash

No response

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

swift-driver version: 1.127.14.1 Apple Swift version 6.2 (swiftlang-6.2.0.19.9 clang-1700.3.19.1)
Target: arm64-apple-macosx26.0
Darwin hapuku-QM17NWPXNV-DS 25.0.0 Darwin Kernel Version 25.0.0: Mon Aug 25 21:17:51 PDT 2025; root:xnu-12377.1.9~3/RELEASE_ARM64_T6020 arm64

[bkhouri]

You can depend on 0.7.1 until this is fixed in SwiftPM. The swift-markdown project updated the code to put the unsafe flag in a compiler conditional.

[nekrich]

Yeah, I saw their release with the fix, but still believe this bug belongs to SPM.

[dschaefer2]

Yeah, I saw their release with the fix, but still believe this bug belongs to SPM.

Definitely. This error shouldn't happen in 6.2.

[dschaefer2]

Ah, swift-markdown has their swift-tools-version set to 5.7. The unsafe flags feature needs 6.2. Forwarding there.