ci: add x86_64-apple-darwin lane (Linux cross via mac_cross_linux)

.github/workflows/release-auto.yml

@@ -175,6 +175,19 @@ jobs:
             macos_cross: false
             mac_cross_linux: true
 
+          # x86_64-apple-darwin shares the mac_cross_linux template
+          # branch — soldr's apple_sdk fetcher auto-picks
+          # `darwin-x86_64` (thin-x86_64) when the target triple is
+          # `x86_64-apple-darwin`, and `cargo zigbuild --target
+          # x86_64-apple-darwin` resolves the SDKROOT + frameworks
+          # identically to the arm64 lane. Closes Lane 3 of soldr#1006.
+          - target: x86_64-apple-darwin
+            runner: ubuntu-latest
+            binary_ext: ""
+            linux_cross: false
+            macos_cross: false
+            mac_cross_linux: true
+
           - target: x86_64-pc-windows-msvc
             runner: windows-latest
             binary_ext: ".exe"

.github/workflows/template_native_build.yml

@@ -163,7 +163,7 @@ jobs:
         run: |
           if [ "${{ inputs.mac_cross_linux }}" = "true" ]; then
             # Linux → aarch64-apple-darwin: zigbuild + soldr-managed SDK.
-            # Identical recipe to ci/docker-mac-arm64-cross/build.sh, which
+            # Identical recipe to ci/docker-mac-cross/build.sh, which
             # validates this same path against a minimal ubuntu:24.04 image.
             soldr cargo zigbuild --release --target ${{ inputs.target }} \
               -p fbuild-cli \

ci/docker-mac-arm64-cross/Dockerfile → ci/docker-mac-cross/Dockerfile

@@ -1,19 +1,23 @@
-# Simulate the FastLED/fbuild GitHub Actions release runner for the
-# `aarch64-apple-darwin` lane on **Linux x86_64**, with no Apple-side
-# tooling and no pre-installed Rust toolchain. Soldr bootstraps
-# everything else.
+# Simulate the FastLED/fbuild GitHub Actions release runners for both
+# Apple targets — aarch64-apple-darwin AND x86_64-apple-darwin — on
+# **Linux x86_64**, with no Apple-side tooling and no pre-installed
+# Rust toolchain. Soldr bootstraps everything else.
 #
-# This is the "NO CHEATING" proof: we ship a vanilla Debian base + the
+# This is the "NO CHEATING" proof: we ship a vanilla Ubuntu base + the
 # absolute minimum apt deps, and soldr brings rustup, the pinned
 # toolchain, zig, the Apple SDK, and `cargo-zigbuild` — exactly the
 # story soldr#997 promised for cross-compile completeness.
 #
 # Build:
-#   docker build -f ci/docker-mac-arm64-cross/Dockerfile -t fbuild-mac-arm64-cross .
+#   docker build -f ci/docker-mac-cross/Dockerfile -t fbuild-mac-cross .
 #
 # Run (from repo root):
-#   docker run --rm -v "$PWD:/src" -w /src fbuild-mac-arm64-cross \
-#       ./ci/docker-mac-arm64-cross/build.sh
+#   # aarch64 (default):
+#   docker run --rm -v "$PWD:/src" -w /src fbuild-mac-cross \
+#       ./ci/docker-mac-cross/build.sh
+#   # x86_64:
+#   docker run --rm -v "$PWD:/src" -w /src fbuild-mac-cross \
+#       ./ci/docker-mac-cross/build.sh x86_64-apple-darwin
 
 # ubuntu:24.04 is exactly what `ubuntu-latest` is on GitHub Actions
 # right now (the runners moved off 22.04 in 2025-Q4). Picking it

ci/docker-mac-arm64-cross/README.md → ci/docker-mac-cross/README.md

@@ -1,29 +1,39 @@
-# `ci/docker-mac-arm64-cross/` — Linux → `aarch64-apple-darwin` simulator
+# `ci/docker-mac-cross/` — Linux → `(aarch64|x86_64)-apple-darwin` simulator
 
-Reproduces fbuild's `aarch64-apple-darwin` release lane on **Linux x86_64**
-with **no Apple-side tooling and no pre-installed Rust toolchain**. Soldr
+Reproduces fbuild's Apple release lanes on **Linux x86_64** with **no
+Apple-side tooling and no pre-installed Rust toolchain**. Soldr
 bootstraps rustup, the pinned 1.94.1 channel, zig, the Apple SDK, and
 `cargo-zigbuild` from a vanilla `ubuntu:24.04` base.
 
 This is the proof-of-concept that lets fbuild's release pipeline drop
-its `macos-latest` runner for the mac-arm64 lane and replace it with the
+its `macos-latest` runners entirely and route both mac arches to the
 same `ubuntu-latest` lane every other target already uses.
 
 ## Build + run
 
 ```bash
-# From the fbuild repo root:
-docker build -f ci/docker-mac-arm64-cross/Dockerfile -t fbuild-mac-arm64-cross .
-docker run --rm -v "$PWD:/src" -w /src fbuild-mac-arm64-cross \
-    bash ci/docker-mac-arm64-cross/build.sh
+# From the fbuild repo root, build the docker image once:
+docker build -f ci/docker-mac-cross/Dockerfile -t fbuild-mac-cross .
+
+# Default: aarch64-apple-darwin (Apple Silicon)
+docker run --rm -v "$PWD:/src" -w /src fbuild-mac-cross \
+    bash ci/docker-mac-cross/build.sh
+
+# Intel mac:
+docker run --rm -v "$PWD:/src" -w /src fbuild-mac-cross \
+    bash ci/docker-mac-cross/build.sh x86_64-apple-darwin
 ```
 
-`build.sh` produces three artifacts under `$PWD/staging/` and asserts via
-`file(1)` that each is a `Mach-O 64-bit arm64` binary — the
+`build.sh` produces three artifacts under `$PWD/staging/` and asserts
+via `file(1)` that each is a `Mach-O 64-bit <arch>` binary — the
 `NO CHEATING` gate. If anything regressed and we accidentally produced
 the host Linux binary, `file` reports `ELF 64-bit LSB pie executable,
 x86-64` and the script fails loudly.
 
+The arch check is per-target (`arm64|aarch64` for the Apple Silicon
+lane, `x86_64` for the Intel lane), so neither lane can silently
+fall back to the host triple.
+
 ## Why `ubuntu:24.04` (not `debian:bookworm-slim`)
 
 Soldr's published Linux-gnu binary requires `glibc 2.39`. Debian

ci/docker-mac-arm64-cross/build.sh → ci/docker-mac-cross/build.sh

@@ -1,16 +1,30 @@
 #!/usr/bin/env bash
-# Run inside the `fbuild-mac-arm64-cross` docker image (see Dockerfile).
-# Cross-compiles fbuild + fbuild-daemon + the PyO3 extension to
-# aarch64-apple-darwin using soldr + cargo-zigbuild + soldr's Apple SDK.
+# Run inside the `fbuild-mac-cross` docker image (see Dockerfile).
+# Cross-compiles fbuild + fbuild-daemon + the PyO3 extension to one of
+# the Apple targets using soldr + cargo-zigbuild + soldr's Apple SDK.
+#
+# Usage:
+#   ./build.sh                         # default aarch64-apple-darwin
+#   TARGET=x86_64-apple-darwin ./build.sh  # mac intel
+#   ./build.sh aarch64-apple-darwin    # explicit positional arg
 #
 # Output layout (in $PWD/staging):
-#   fbuild                  ← Mach-O 64-bit executable arm64
-#   fbuild-daemon           ← Mach-O 64-bit executable arm64
-#   _native.abi3.so         ← Mach-O 64-bit dylib arm64 (PyO3 extension)
+#   fbuild                  ← Mach-O 64-bit executable <arch>
+#   fbuild-daemon           ← Mach-O 64-bit executable <arch>
+#   _native.abi3.so         ← Mach-O 64-bit dylib <arch> (PyO3 extension)
 
 set -euo pipefail
 
-TARGET="aarch64-apple-darwin"
+TARGET="${1:-${TARGET:-aarch64-apple-darwin}}"
+case "$TARGET" in
+    aarch64-apple-darwin) MACHO_ARCH_PATTERN="arm64|aarch64" ;;
+    x86_64-apple-darwin)  MACHO_ARCH_PATTERN="x86_64" ;;
+    *)
+        echo "ERROR: unsupported TARGET=$TARGET (expected aarch64-apple-darwin or x86_64-apple-darwin)" >&2
+        exit 2
+        ;;
+esac
+echo "::notice::TARGET=$TARGET (expect Mach-O $MACHO_ARCH_PATTERN)"
 STAGING="${STAGING:-$PWD/staging}"
 mkdir -p "$STAGING"
 
@@ -56,19 +70,19 @@ if [ ! -f "$EXT_SRC" ]; then
 fi
 cp "$EXT_SRC" "$STAGING/_native.abi3.so"
 
-# Verify the output is actually a Mach-O ARM64 binary — this is the
+# Verify the output is actually a Mach-O <arch> binary — this is the
 # `NO CHEATING` gate. If file(1) reports anything other than
-# `Mach-O 64-bit ... arm64` for all three artifacts, the cross-compile
+# `Mach-O 64-bit ... <arch>` for all three artifacts, the cross-compile
 # silently produced the host binary instead and we must fail loudly.
 for f in fbuild fbuild-daemon _native.abi3.so; do
     desc="$(file "$STAGING/$f")"
     echo "  $desc"
-    if ! echo "$desc" | grep -qE "Mach-O.*(arm64|aarch64)"; then
-        echo "ERROR: $f is not Mach-O arm64 — got: $desc" >&2
+    if ! echo "$desc" | grep -qE "Mach-O.*($MACHO_ARCH_PATTERN)"; then
+        echo "ERROR: $f is not Mach-O matching '$MACHO_ARCH_PATTERN' — got: $desc" >&2
         exit 1
     fi
 done
 echo "::endgroup::"
 
-echo "All three artifacts are valid Mach-O arm64. Staging dir: $STAGING"
+echo "All three artifacts are valid Mach-O for $TARGET. Staging dir: $STAGING"
 ls -lh "$STAGING"