Link the inference engine for macOS in a zig container

`docker/macos` builds for aarch64-apple-darwin from Linux with cargo-zigbuild. Zig carries libSystem and the C headers, so tract's SIMD kernels compile and the engine's test binaries and examples link as Mach-O arm64 — the check `cargo check --target` could not do, because tract's build script needs a macOS C compiler. Crates that link an Apple framework (dr-plat's keyring, and so the app) still need the Xcode SDK and fail at the link; macos.md says so.
2026-09-29 22:03:12 -04:00
parent bff12f81a9
commit 064be89a73
3 changed files with 122 additions and 4 deletions
@@ -0,0 +1,48 @@
+# DarkRoom — macOS link check
+#
+# Compiles and links for macOS from Linux, with zig as the linker
+# (cargo-zigbuild). Zig carries macOS's libSystem stubs and C headers, so the
+# crates that need only libSystem — the inference engine, dr-plat — build,
+# link and produce Mach-O test binaries here. Nothing runs: there is no macOS
+# to run them on (docs/dev/macos.md §2). The desktop app needs Apple's
+# framework headers (AppKit, Metal, Security), which only the Xcode SDK
+# carries, so it does not link here.
+#
+# Build:  docker build -t darkroom-macos:latest docker/macos
+# Use:    ./docker/macos/build.sh cargo zigbuild --target aarch64-apple-darwin -p dr-inference-engine --all-targets
+
+FROM docker.io/library/debian:trixie-slim
+
+# Pinned, like the Windows and Android images. Rust matches rust-toolchain.toml.
+ARG RUST_VERSION=1.92.0
+ARG ZIG_VERSION=0.15.2
+ARG ZIG_SHA256=02aa270f183da276e5b5920b1dac44a63f1a49e55050ebde3aecc9eb82f93239
+ARG CARGO_ZIGBUILD_VERSION=0.23.4
+
+ENV DEBIAN_FRONTEND=noninteractive \
+    CARGO_HOME=/opt/cargo \
+    RUSTUP_HOME=/opt/rustup \
+    PATH=/opt/zig:/opt/cargo/bin:$PATH
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        ca-certificates curl git xz-utils \
+        # A host C compiler: build scripts and proc-macros are Linux binaries.
+        gcc libc6-dev \
+        # `file` says Mach-O; the smoke check in build.sh reads it.
+        file \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN curl -fsSL "https://ziglang.org/download/${ZIG_VERSION}/zig-x86_64-linux-${ZIG_VERSION}.tar.xz" -o /tmp/zig.tar.xz \
+    && echo "${ZIG_SHA256}  /tmp/zig.tar.xz" | sha256sum -c - \
+    && mkdir /opt/zig && tar xJf /tmp/zig.tar.xz -C /opt/zig --strip-components=1 \
+    && rm /tmp/zig.tar.xz && zig version
+
+# The components rust-toolchain.toml lists, baked in so rustup does not fetch
+# them inside every run.
+RUN curl -fsSL https://sh.rustup.rs | sh -s -- -y --profile minimal \
+        --default-toolchain "${RUST_VERSION}" \
+        --component rustfmt,clippy,rust-analyzer \
+        --target aarch64-apple-darwin,x86_64-apple-darwin \
+    && cargo install --locked "cargo-zigbuild@${CARGO_ZIGBUILD_VERSION}" \
+    && rm -rf /opt/cargo/registry \
+    && chmod -R a+rwX /opt/cargo /opt/rustup