Use Windows arm64 hosted runners for build-windows

Author: hugovk

.github/workflows/build.yml

@@ -156,28 +156,18 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os:
-          - windows-latest
         arch:
           - x64
+          - Win32
+          - arm64
         free-threading:
           - false
           - true
-        include:
-          # Forks don't have access to Windows on Arm runners. These jobs are skipped below:
-          - os: ${{ github.repository_owner == 'python' && 'windows-aarch64' || 'windows-latest' }}
-            arch: arm64
-            free-threading: false
-          # Forks don't have access to Windows on Arm runners. These jobs are skipped below:
-          - os: ${{ github.repository_owner == 'python' && 'windows-aarch64' || 'windows-latest' }}
-            arch: arm64
-            free-threading: true
-          - os: windows-latest
-            arch: Win32
-            free-threading: false
+        exclude:
+          # Skip Win32 on free-threaded builds
+          - { arch: Win32, free-threading: true }
     uses: ./.github/workflows/reusable-windows.yml
     with:
-      os: ${{ matrix.os }}
       arch: ${{ matrix.arch }}
       free-threading: ${{ matrix.free-threading }}
 

.github/workflows/reusable-windows.yml

@@ -3,10 +3,6 @@ name: Reusable Windows
 on:
   workflow_call:
     inputs:
-      os:
-        description: OS to run on
-        required: true
-        type: string
       arch:
         description: CPU architecture
         required: true
@@ -25,7 +21,7 @@ env:
 jobs:
   build:
     name: Build and test (${{ inputs.arch }})
-    runs-on: ${{ inputs.os }}
+    runs-on: ${{ inputs.arch == 'arm64' && 'windows-11-arm' || 'windows-latest' }}
     timeout-minutes: 60
     env:
       ARCH: ${{ inputs.arch }}
@@ -37,21 +33,15 @@ jobs:
       if: inputs.arch != 'Win32'
       run: echo "::add-matcher::.github/problem-matchers/msvc.json"
     - name: Build CPython
-      # Forks don't have access to Windows on Arm runners. Skip those:
-      if: inputs.arch != 'arm64' || github.repository_owner == 'python'
       run: >-
         .\\PCbuild\\build.bat
         -e -d -v
         -p "${ARCH}"
         ${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
       shell: bash
     - name: Display build info
-      # Forks don't have access to Windows on Arm runners. Skip those:
-      if: inputs.arch != 'arm64' || github.repository_owner == 'python'
       run: .\\python.bat -m test.pythoninfo
     - name: Tests
-      # Forks don't have access to Windows on Arm runners. Skip those:
-      if: inputs.arch != 'arm64' || github.repository_owner == 'python'
       run: >-
         .\\PCbuild\\rt.bat
         -p "${ARCH}"