Merge the macOS island fixes of ni/1-libnode-loader

The libnode-linux action becomes .github/actions/libnode, which serves
the Linux x64 and macOS lanes: the libnode-packs cache for the runner's
platform, else the development pack.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/actions/libnode/action.yml

@@ -1,8 +1,8 @@
-name: libnode pack (Linux x64)
+name: libnode pack (Linux x64, macOS)
 description: >-
-  Provide the linux-x64 libnode pack for the Node island tests and export
+  Provide the runner's libnode pack for the Node island tests and export
   SCRIPTC_LIBNODE. Restores the libnode build that the libnode-packs
-  workflow cached and assembles @scriptc/libnode-linux-x64-gnu from it (the
+  workflow cached and assembles @scriptc/libnode-<platform> from it (the
   bridge compiles in seconds; Node is never built here). Until that cache
   exists for this ref, it falls back to the pinned, checksum-verified
   development pack (packages/libnode-common/dev-pack.json). Fails the job if
@@ -10,33 +10,44 @@ description: >-
 runs:
   using: composite
   steps:
+    - name: Name the runner's pack
+      id: target
+      shell: bash
+      run: |
+        case "$RUNNER_OS-$RUNNER_ARCH" in
+          Linux-X64) platform=linux-x64-gnu toolchain=manylinux_2_28-gcc-toolset-14 bridge=libscr_node_bridge.so ;;
+          macOS-ARM64) platform=darwin-arm64 toolchain=macos-15-xcode-clang bridge=libscr_node_bridge.dylib ;;
+          macOS-X64) platform=darwin-x64 toolchain=macos-15-xcode-clang bridge=libscr_node_bridge.dylib ;;
+          *) echo "::error::no libnode pack for $RUNNER_OS $RUNNER_ARCH"; exit 1 ;;
+        esac
+        printf 'platform=%s\ntoolchain=%s\nbridge=%s\n' "$platform" "$toolchain" "$bridge" >> "$GITHUB_OUTPUT"
     - name: Compute the libnode cache key
       id: key
       shell: bash
       env:
-        SCRIPTC_LIBNODE_TOOLCHAIN: manylinux_2_28-gcc-toolset-14
-      run: node packages/libnode-common/scripts/cache-key.mjs --platform linux-x64-gnu >> "$GITHUB_OUTPUT"
+        SCRIPTC_LIBNODE_TOOLCHAIN: ${{ steps.target.outputs.toolchain }}
+      run: node packages/libnode-common/scripts/cache-key.mjs --platform ${{ steps.target.outputs.platform }} >> "$GITHUB_OUTPUT"
     - uses: actions/cache/restore@v4
       id: libnode
       with:
         path: .libnode-cache/${{ steps.key.outputs.path }}
         key: ${{ steps.key.outputs.key }}
-    - name: Assemble @scriptc/libnode-linux-x64-gnu
+    - name: Assemble @scriptc/libnode-${{ steps.target.outputs.platform }}
       if: steps.libnode.outputs.cache-hit == 'true'
       shell: bash
       env:
-        SCRIPTC_LIBNODE_TOOLCHAIN: manylinux_2_28-gcc-toolset-14
+        SCRIPTC_LIBNODE_TOOLCHAIN: ${{ steps.target.outputs.toolchain }}
         SCRIPTC_LIBNODE_CACHE: ${{ github.workspace }}/.libnode-cache
       run: |
-        node packages/libnode-linux-x64-gnu/scripts/build.mjs --from-cache
-        node packages/libnode-common/scripts/verify.mjs packages/libnode-linux-x64-gnu
-        echo "SCRIPTC_LIBNODE=$GITHUB_WORKSPACE/packages/libnode-linux-x64-gnu" >> "$GITHUB_ENV"
+        node packages/libnode-${{ steps.target.outputs.platform }}/scripts/build.mjs --from-cache
+        node packages/libnode-common/scripts/verify.mjs packages/libnode-${{ steps.target.outputs.platform }}
+        echo "SCRIPTC_LIBNODE=$GITHUB_WORKSPACE/packages/libnode-${{ steps.target.outputs.platform }}" >> "$GITHUB_ENV"
     - uses: actions/cache@v4
       if: steps.libnode.outputs.cache-hit != 'true'
       id: devpack
       with:
         path: ${{ runner.temp }}/libnode-dev-pack
-        key: libnode-dev-pack-linux-x64-${{ hashFiles('packages/libnode-common/dev-pack.json', 'packages/libnode-common/build-pack.mjs', 'packages/libnode-common/fetch-dev-pack.mjs', 'packages/libnode-common/bridge/**', 'packages/runtime/src/scr_node_bridge.h') }}
+        key: libnode-dev-pack-${{ steps.target.outputs.platform }}-${{ hashFiles('packages/libnode-common/dev-pack.json', 'packages/libnode-common/build-pack.mjs', 'packages/libnode-common/fetch-dev-pack.mjs', 'packages/libnode-common/bridge/**', 'packages/runtime/src/scr_node_bridge.h') }}
     - name: Assemble the development pack
       if: steps.libnode.outputs.cache-hit != 'true'
       shell: bash
@@ -50,4 +61,4 @@ runs:
       shell: bash
       run: |
         test -f "$SCRIPTC_LIBNODE/manifest.json"
-        test -f "$SCRIPTC_LIBNODE/libscr_node_bridge.so"
+        test -f "$SCRIPTC_LIBNODE/${{ steps.target.outputs.bridge }}"

.github/workflows/ci.yml

@@ -215,7 +215,7 @@ jobs:
       # Node island tests (`// @requires-libnode` corpus programs and
       # node-island.test.ts) load Node from a libnode pack, and fail rather
       # than skip in this lane when none is configured.
-      - uses: ./.github/actions/libnode-linux
+      - uses: ./.github/actions/libnode
       # Ubuntu pipes core dumps to apport, and RLIMIT_CORE does not limit a
       # piped dump. The kernel then streams every page of the runtime's
       # reserved allocator address space through the pipe, so each expected
@@ -284,6 +284,9 @@ jobs:
           path: ${{ runner.temp }}
       - run: tar -xzf "$RUNNER_TEMP/native-darwin-arm64.tar.gz"
       - run: pnpm build
+      # Node island tests load Node from a libnode pack, and fail rather
+      # than skip on macOS CI when none is configured.
+      - uses: ./.github/actions/libnode
       - name: Tests (${{ (github.event_name != 'schedule' && inputs.macos_suite != 'full') && 'darwin suite' || 'corpus and integration suites' }})
         run: node scripts/ci-test.mjs
 
@@ -704,6 +707,12 @@ jobs:
           path: ${{ runner.temp }}
       - run: tar -xzf "$RUNNER_TEMP/native-darwin-arm64.tar.gz"
       - run: pnpm build
+      # Node island tests load Node from a libnode pack, and fail rather
+      # than skip on macOS CI when none is configured.
+      - uses: ./.github/actions/libnode
+      - name: Node island harness
+        if: matrix.shard == 1
+        run: pnpm test tests/harness/node-island packages/libnode-common
       - name: No-clang assembly/object contract
         if: matrix.shard == 1
         run: pnpm test packages/cli/test/native-output.test.ts
@@ -761,7 +770,8 @@ jobs:
     if: ${{ needs.validation_scope.outputs.full == 'true' && needs.lanes.outputs.macos == 'true' }}
     name: test (macOS x64 LLVM artifacts, no clang)
     runs-on: macos-15-intel
-    timeout-minutes: 20
+    # The Node island tests take most of it.
+    timeout-minutes: 45
     steps:
       - uses: actions/checkout@v4
       - uses: pnpm/action-setup@v4
@@ -776,6 +786,15 @@ jobs:
         with:
           target: darwin-x64
       - run: pnpm build
+      # Node island tests load Node from a libnode pack, and fail rather
+      # than skip on macOS CI when none is configured.
+      - uses: ./.github/actions/libnode
+      - name: Node islands (Intel)
+        run: >-
+          pnpm test tests/harness/node-island packages/libnode-common
+          && pnpm test tests/harness/differential.test.ts -t ' (68[0-9][0-9]|7661|7662)-'
+        env:
+          SCRIPTC_TEST_WORKERS: "3"
       - name: Intel Mach-O no-clang object contract
         run: |
           mkdir -p "$RUNNER_TEMP/traps"