`unsafeFlags` introduced in Markdown 0.7.0 causes SwiftPM dependency resolution failures

[dlskawns96]

Hello,

Starting from version 0.7.0, the Markdown target includes the following in its swiftSettings:

swiftSettings: [
    .unsafeFlags(["-Xcc", "-DCMARK_GFM_STATIC_DEFINE"],
                 .when(platforms: [.windows])),
]

This introduces unsafeFlags into the package manifest. Unfortunately, SwiftPM disallows using packages that contain unsafe build flags as normal (tagged) dependencies in application targets. As a result, projects that depend on swift-markdown via SwiftPM are now unable to resolve the package, failing with the error:

the target 'Markdown' in product 'Markdown' contains unsafe build flags

This is particularly problematic for iOS/macOS projects and CI environments (e.g. Bitrise, Xcode Cloud), which previously built successfully with versions ≤ 0.6.x.

Could you please clarify whether this was intentional, and if there is a recommended workaround for SwiftPM clients?

Thanks!

[nekrich]

The same here. I depend on the swift-format but can't build my project on macOS and Linux platforms.

[nekrich]

Lucky me, the swift-format doesn't lock the swift-markdown version.

So I locked the version in my Package.swift by adding a dependency that is not used 🤷.

dependencies: [
  // ....
  .package(url: "https://github.com/swiftlang/swift-markdown.git", "0.6.0"..<"0.7.0"),
]

@dlskawns96 , maybe this will help you too?

Of course, there are new warnings, but I can live with them for now:

warning: 'swift-format': Conflicting identity for swift-markdown: dependency 'github.com/apple/swift-markdown' and dependency 'github.com/swiftlang/swift-markdown' both point to the same package identity 'swift-markdown'. The dependencies are introduced through the following chains: (A) tool->github.com/swiftlang/swift-format->github.com/apple/swift-markdown (B) /tool->github.com/swiftlang/swift-markdown. If there are multiple chains that lead to the same dependency, only the first chain is shown here. To see all chains use debug output option. To resolve the conflict, coordinate with the maintainer of the package that introduces the conflicting dependency. This will be escalated to an error in future versions of SwiftPM.
warning: 'tool': dependency 'swift-markdown' is not used by any target

[dlskawns96]

@nekrich
Nice workaround! 😄
I’m also using the same trick—locking swift-markdown to 0.6.0 as a temporary fix.
Not the cleanest solution, but it gets the job done (despite those annoying warnings).

[QuietMisdreavus]

Oh geez, i would say that this is definitely not intentional. I think the PR you opened is a good approach, so i'll go ahead and merge that and start some cherry-picks so i can release a 0.7.1 tag as soon as i can.

[QuietMisdreavus]

Alright, that's all set, Swift-Markdown 0.7.1 has been tagged and pushed; let me know if that resolves your issue.

[yorkepb]

This resolved it for me 👍🏻

[dlskawns96]

@QuietMisdreavus This resolved it for me as well. Both local and CI builds are now working without any issues 👍

[kkebo]

On Swift 5.9 on Windows, it seems that it hasn't yet been resolved.

• The CI job "Test / Windows (5.9 - windows-2022)" always fails swift-format#1094