Wave 3 (0.6.0): zero-OpenCombine builds on Apple platforms#22
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Since #11 every source file selects its backend with #if canImport(Combine): Apple platforms compile against native Combine, so linking OpenCombine there was pure dead weight (5 extra modules built into every Apple consumer). The product dependency now carries .when(platforms: [.wasi, .linux, .android, .windows, .openbsd]) on all three consuming targets - every non-Apple platform PackageDescription 6.3 exposes, because canImport(Combine) is false on all of them, not just WASI; listing only .wasi would silently break Linux consumers. .freebsd is gated @available(_PackageDescription 999.0) and cannot be listed yet. The package-level .package(url:) declaration stays (full removal deferred), so OpenCombine and its transitive swift-syntax are still fetched at resolution time on every platform - only the build/link footprint drops: a clean macOS build now compiles zero OpenCombine sources and the example binary links only the native Combine framework (verified via otool -L).
The opencombine-latest job only ran swift build/test on macOS. After the platform-conditional dependency (#15) a host build links native Combine and compiles zero OpenCombine code, which would have made the canary vacuous: it could never again detect upstream OpenCombine breakage. Add the same version-matched wasm SDK install + wasm build steps the jskit-latest job already uses, so the canary actually compiles the library against the patched OpenCombine. Host steps are kept as a resolution smoke check. actionlint: the only findings are two pre-existing SC2010 warnings in the untouched Select Xcode steps, identical on main; this change adds none.
Consumers need to know what the conditional dependency changes and - just as important - what it does not: no public API is removed or deprecated, WASI/Linux behavior is identical, and OpenCombine (plus its transitive swift-syntax) is still fetched at resolution time on Apple platforms; only compilation and linkage drop. README and the DocC landing page state the per-platform linkage story; CHANGELOG opens the Unreleased (0.6.0) section with the declared packaging change; CONTRIBUTING's dependency policy now explains the platform-list invariant (keep it equal to the set of platforms where canImport(Combine) is false) so future edits do not silently unlink a platform.
ikorich
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enhancement
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Motivation
Final roadmap ticket (#15, re-scoped to 0.6.0): OpenCombine has been dormant since 2023 and is this library's biggest supply-chain risk. Since #11, Apple builds use native Combine — but OpenCombine was still compiled and linked everywhere. This PR removes it from the Apple build graph entirely.
Changes
.when(platforms: [.wasi, .linux, .android, .windows, .openbsd])on all three consuming targets — every platform wherecanImport(Combine)is false. Dropping any of these (e.g..linux) would silently break those consumers, hence the exhaustive list (documented in the manifest;.freebsdis still_PackageDescription 999.0-gated at tools 6.3).OpenCombineJS.abi.json, andotool -Lon the example binary shows nativeCombine.frameworkonly..packagedeclaration is removed in a future major.opencombine-latestjob would have become vacuous (host builds now compile zero OpenCombine) — it now mirrors the jskit job's wasm-SDK build steps; host steps remain as a resolution smoke check. actionlint: zero new findings.Unreleased (0.6.0)) updated.Test plan
swift build+swift test— 35/6 green.wasm32-unknown-wasip1): build +js test— 81/22 green.swiftformat --lintclean.Closes #15