[rayman-zhao]

Supersedes #936 — resubmitted after removing accidentally committed local build artifacts; the actual changes are identical. (That PR could not be reopened because its branch was force-pushed after closing.)

Motivation

swift-java currently pins swift-subprocess to 0.4.0..<0.5.0, while Subprocess 1.0 has been released (shipping with Swift 6.4). The 0.4 pin makes it impossible to use swift-java in a package graph that also contains a package requiring swift-subprocess 1.0, since SwiftPM must pick a single version for the whole graph. Subprocess 1.0.0 also includes a PATH-resolution security fix for Executable.name(_:).

Changes

• Package.swift: "0.4.0"..<"0.5.0" -> "1.0.0"..<"2.0.0" (the SubprocessFoundation trait is kept; it now provides .data(limit:))
• JavaCallbacksBuildCommand.swift: FileDescriptorOutput.standardOutput/.standardError -> .currentStandardOutput/.currentStandardError (renamed in 0.5)
• JavaDependencyResolver.swift, CompileJavaTool.swift: drop ?? "" fallbacks — StringOutput results are non-optional String since 1.0
• StaticBuildConfigPluginExecutable.swift: replace the if let error = result.standardError optional binding with a plain non-optional check (required: the value is no longer optional)

Testing

Built on Windows (Swift 6.4.1, JDK 25): swift build --target swift-java, --target StaticBuildConfigPluginExecutable, and --target SwiftJavaToolLibTests all pass with swift-subprocess resolved at 1.0.2.

[rayman-zhao]

The failing Test (Swift) (noble swift:6.1.3) job is a toolchain-floor conflict rather than a code issue:

error: Dependencies could not be resolved because 'swift-subprocess' >= 0.5.0
contains incompatible tools version (6.2.0) and root depends on 'swift-subprocess' 1.0.0..<2.0.0.

swift-subprocess 0.5+ declares swift-tools-version: 6.2, so it cannot be resolved by the 6.1.3 toolchain at all — which I suspect is exactly why this package is pinned to 0.4.x today. All other jobs (6.3, nightly, macOS, benchmarks, samples, soundness) pass.

So this bump inherently means dropping Swift 6.1 toolchain support, which is a project-policy call. Happy to go either way:

• If you're ready to raise the minimum toolchain, I can extend this PR with the swift-tools-version bump and remove 6.1.3 from the CI matrix.
• If 6.1 support needs to stay for now, closing/deferring this PR is completely fine. (Context for the motivation: unblocking package graphs that need swift-java alongside a package depending on swift-subprocess 1.0, plus picking up the Executable.name(_:) PATH-resolution security fix.)

[ktoso]

Hm yeah I'll have to check with adopters. We might need to be slow to drop 6.1 even though we're not officially a 1.0...

Thank you for the pr in any case.
I'll follow up soon!