error: the target 'SwiftJava' in product 'JExtractSwiftPlugin' contains unsafe build flags

[gmondada]

I'm using the JExtractSwiftPlugin in my Package.swift. When building I get the error:

error: 'my-target': the target 'SwiftJava' in product 'SwiftJava' contains unsafe build flags
error: 'my-target': the target 'SwiftJava' in product 'JExtractSwiftPlugin' contains unsafe build flags

• swift-java version: .package(url: "https://github.com/swiftlang/swift-java.git", exact: "0.1.0")
• toolchain: 6.3-snapshot-2026-02-27
• tools version: // swift-tools-version: 6.3
• host: macOS 26.3.1 (a)
• SDK: swift-6.3-DEVELOPMENT-SNAPSHOT-2026-02-27-a_android
• Compiled with command: swiftly run swift build --product MyProduct --swift-sdk aarch64-unknown-linux-android28

This patch solves the problem: https://github.com/swiftlang/swift-java/pull/635/commits

[gmondada]

Example of package that has the problem:

demo-abc.zip

To be compiled with swiftly run swift build, with the toolchain mentioned above.

[dschaefer2]

"Good" news is that I can reproduce this. It also happens in 6.2 so this is a scenario the original change didn't take into account. Debugging more and will put together a PR.

[dschaefer2]

Ah, it's because you're using 0.1.0 of swift-java that has the swift-tools-version of 6.1. The package that has the unsafe flags has to have a tools version of 6.2 ore more. You need to use a newer swift-java.

[dschaefer2]

Oh, wait, swift-java still has the 6.1 version tag.

[dschaefer2]

@ktoso