feat(watchos): target arm64 (aarch64-apple-watchos) for device builds#5034
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arm64_32 cannot host Perry's NaN-boxed values (48-bit pointer tags need 64-bit usize), so real-watch builds never linked. watchOS 26 moved S9+ watches to full arm64, making the device target viable: swap the device triple to aarch64-apple-watchos, Swift/linker triples to arm64-apple-watchos26.0, and raise the watch bundle MinimumOSVersion accordingly (simulator keeps 10.0). Note: App Store submissions additionally require MinimumOSVersion >= 27.0 for arm64-only watch apps (arm64_32 slice mandatory below that).
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Why
Real-watch builds (
--target watchos) have never linked: the device triple wasarm64_32-apple-watchos, and Perry's NaN-boxed value representation (48-bit pointer masks, tags in the high 16 bits of a 64-bit word) fundamentally requires 64-bitusize—perry-runtimedoesn't even compile for arm64_32 ("literal out of range for usize" in value.rs).watchOS 26 moved S9-and-later watches to full arm64, so a 64-bit device target now exists. Apple also requires arm64 for all new watchOS App Store submissions since July 2025.
What
arm64_32-apple-watchos→aarch64-apple-watchos(codegen helpers + native-lib target mapping)arm64_32-apple-watchos10.0→arm64-apple-watchos26.0(link, platform_cmd, watchos-widget)MinimumOSVersion: 26.0 for device builds (simulator keeps 10.0)-Z build-stdinvocation the tier-3 target needsValidation
Built a real game (Bloom Jump) end to end:
perry-runtime+perry-ui-watchosvia nightly build-std foraarch64-apple-watchos, game compiled/linked with--features watchos-swift-app, produced a Mach-Oplatform WATCHOS minos 26.0arm64 executable, signed and accepted by App Store Connect (uploaded as a watch-only app, processing).Notes
aarch64-apple-watchosis a tier-3 Rust target: runtime libs needcargo +nightly build -Z build-std=std,panic_abort. Worth wiring into release-packages.yml so PERRY_RUNTIME_DIR users get prebuilt .a files.MinimumOSVersion >= 27.0for arm64-only watch apps (below that an arm64_32 slice is mandatory). 26.0 is kept here because it allows Xcode dev-installs on S9+ watches running watchOS 26; store packaging can re-stamp withvtool -set-build-version watchos 27.0. Could alternatively make this a perry.toml knob — happy to follow up.perry publish watchossupport could build on this).