[3.12] Move macOS matrix to the calling workflow (GH-121809) (#122330)

.github/workflows/build.yml

@@ -286,15 +286,38 @@ jobs:
       arch: ${{ matrix.arch }}
 
   build_macos:
-    name: 'macOS'
+    name: >-
+      macOS
+      ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
     needs: check_source
     if: needs.check_source.outputs.run_tests == 'true'
+    strategy:
+      fail-fast: false
+      matrix:
+        # Cirrus and macos-14 are M1, macos-13 is default GHA Intel.
+        # macOS 13 only runs tests against the GIL-enabled CPython.
+        # Cirrus used for upstream, macos-14 for forks.
+        os:
+        - ghcr.io/cirruslabs/macos-runner:sonoma
+        - macos-14
+        - macos-13
+        is-fork:  # only used for the exclusion trick
+        - ${{ github.repository_owner != 'python' }}
+        free-threading:
+        - false
+        # - true
+        exclude:
+        - os: ghcr.io/cirruslabs/macos-runner:sonoma
+          is-fork: true
+        - os: macos-14
+          is-fork: false
+        - os: macos-13
+          free-threading: true
     uses: ./.github/workflows/reusable-macos.yml
     with:
       config_hash: ${{ needs.check_source.outputs.config_hash }}
-      # Cirrus and macos-14 are M1, macos-13 is default GHA Intel.
-      # Cirrus used for upstream, macos-14 for forks.
-      os-matrix: '["ghcr.io/cirruslabs/macos-runner:sonoma", "macos-14", "macos-13"]'
+      free-threading: ${{ matrix.free-threading }}
+      os: ${{ matrix.os }}
 
   build_ubuntu:
     name: >-

.github/workflows/reusable-macos.yml

@@ -8,13 +8,14 @@ on:
         required: false
         type: boolean
         default: false
-      os-matrix:
-        required: false
+      os:
+        description: OS to run the job
+        required: true
         type: string
 
 jobs:
   build_macos:
-    name: build and test (${{ matrix.os }})
+    name: build and test (${{ inputs.os }})
     timeout-minutes: 60
     env:
       HOMEBREW_NO_ANALYTICS: 1
@@ -22,18 +23,7 @@ jobs:
       HOMEBREW_NO_INSTALL_CLEANUP: 1
       HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK: 1
       PYTHONSTRICTEXTENSIONBUILD: 1
-    strategy:
-      fail-fast: false
-      matrix:
-        os: ${{fromJson(inputs.os-matrix)}}
-        is-fork:
-          - ${{ github.repository_owner != 'python' }}
-        exclude:
-          - os: "ghcr.io/cirruslabs/macos-runner:sonoma"
-            is-fork: true
-          - os: "macos-14"
-            is-fork: false
-    runs-on: ${{ matrix.os }}
+    runs-on: ${{ inputs.os }}
     steps:
     - uses: actions/checkout@v4
     - name: Runner image version
@@ -42,7 +32,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: config.cache
-        key: ${{ github.job }}-${{ matrix.os }}-${{ env.IMAGE_VERSION }}-${{ inputs.config_hash }}
+        key: ${{ github.job }}-${{ inputs.os }}-${{ env.IMAGE_VERSION }}-${{ inputs.config_hash }}
     - name: Install Homebrew dependencies
       run: brew install pkg-config openssl@3.0 xz gdbm tcl-tk
     - name: Configure CPython