Add CI for Windows ARM64 Python wheel

.github/workflows/build_python_windows_arm64.yml

@@ -0,0 +1,108 @@
+name: Build Windows ARM64 Python Wheels
+
+on:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  build-sdist:
+    name: Build Python source distribution
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout source
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8  # v6.0.1
+
+      - name: Set up Python
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405  # v6.2.0
+        with:
+          python-version: "3.12"
+
+      - name: Set up Bazel
+        uses: bazel-contrib/setup-bazel@c5acdfb288317d0b5c0bbd7a396a3dc868bb0f86  # v0.19.0
+        with:
+          bazelisk-cache: true
+          repository-cache: true
+
+      - name: Build source distribution
+        run: |
+          bazel build //python/dist:source_wheel
+          mkdir dist
+          cp bazel-bin/python/dist/protobuf-*.tar.gz dist/
+
+      - name: Upload source distribution
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f  # v6.0.0
+        with:
+          name: protobuf-sdist
+          path: dist/protobuf-*.tar.gz
+          if-no-files-found: error
+
+  build-wheels:
+    name: Build Windows ARM64 wheels
+    needs: build-sdist
+    runs-on: windows-11-arm
+    defaults:
+      run:
+        shell: pwsh
+    steps:
+      - name: Set up Python
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405  # v6.2.0
+        with:
+          python-version: "3.12"
+          architecture: arm64
+
+      - name: Download source distribution
+        uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131  # v7.0.0
+        with:
+          name: protobuf-sdist
+          path: sdist
+
+      - name: Extract source distribution
+        run: |
+          $sdists = @(Get-ChildItem sdist -Filter protobuf-*.tar.gz -File)
+          if ($sdists.Count -ne 1) {
+            throw "Expected one source distribution, found $($sdists.Count)"
+          }
+
+          tar -xzf $sdists[0].FullName -C sdist
+          $sources = @(Get-ChildItem sdist -Filter protobuf-* -Directory)
+          if ($sources.Count -ne 1) {
+            throw "Expected one extracted source directory, found $($sources.Count)"
+          }
+
+          "PACKAGE_DIR=$($sources[0].FullName)" >> $env:GITHUB_ENV
+
+      - name: Install cibuildwheel
+        run: python -m pip install "cibuildwheel==4.1.0"
+
+      - name: Build and test wheels
+        env:
+          CIBW_ARCHS_WINDOWS: ARM64
+          CIBW_BUILD: "cp311-* cp312-* cp313-* cp314-*"
+          CIBW_BUILD_VERBOSITY: "1"
+          CIBW_TEST_COMMAND: >-
+            python -c "import platform;
+            from google._upb import _message;
+            assert platform.machine() == 'ARM64';
+            assert _message.__file__.endswith('.pyd')"
+        run: python -m cibuildwheel $env:PACKAGE_DIR --output-dir wheelhouse
+
+      - name: Validate wheel artifacts
+        run: |
+          $wheels = @(Get-ChildItem wheelhouse -Filter *.whl -File)
+          if ($wheels.Count -ne 4) {
+            throw "Expected four wheels, found $($wheels.Count)"
+          }
+
+          $invalidWheels = @($wheels | Where-Object Name -NotMatch '-win_arm64\.whl$')
+          if ($invalidWheels.Count -ne 0) {
+            throw "Unexpected wheel platform tags: $($invalidWheels.Name -join ', ')"
+          }
+
+      - name: Upload wheels
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f  # v6.0.0
+        with:
+          name: protobuf-windows-arm64-wheels
+          path: wheelhouse/*.whl
+          if-no-files-found: error

python/dist/BUILD.bazel

@@ -304,8 +304,6 @@ pkg_files(
     strip_prefix = strip_prefix.from_root(""),
 )
 
-# NOTE: This package currently only works for macos and ubuntu, MSVC users
-# should use a binary wheel.
 pkg_tar(
     name = "source_tarball",
     srcs = [

python/dist/setup.py

@@ -13,6 +13,7 @@
 import sys
 
 from setuptools import Extension, find_namespace_packages, setup
+from setuptools.command.build_ext import build_ext
 
 
 def GetVersion():
@@ -31,13 +32,21 @@ def GetVersion():
     return file_globals['__version__']
 
 
+class _BuildExt(build_ext):
+
+  def build_extensions(self):
+    if self.compiler.compiler_type == 'mingw32':
+      for extension in self.extensions:
+        extension.extra_link_args = (
+            extension.extra_link_args or []
+        ) + ['-static']
+    super().build_extensions()
+
+
 current_dir = os.path.dirname(os.path.abspath(__file__))
-extra_link_args = []
 extra_compile_args = []
 
-if sys.platform.startswith('win'):
-  extra_link_args = ['-static']
-else:
+if not sys.platform.startswith('win'):
   extra_compile_args = ['-fvisibility=hidden']
 
 # If at some point the fasttable decoder is ready for prime time, we could
@@ -82,13 +91,13 @@ def GetVersion():
     ],
     packages=find_namespace_packages(include=['google*']),
     install_requires=[],
+    cmdclass={'build_ext': _BuildExt},
     ext_modules=[
         Extension(
             'google._upb._message',
             srcs,
             include_dirs=[current_dir, os.path.join(current_dir, 'utf8_range')],
             language='c',
-            extra_link_args=extra_link_args,
             extra_compile_args=extra_compile_args,
         )
     ],

python/message.c

@@ -1098,7 +1098,10 @@ bool PyUpb_Message_IsFrozen(PyObject* _self) {
  * Attribute lookup must find both message fields and base class methods like
  * msg.SerializeToString().
  */
-__attribute__((flatten)) static PyObject* PyUpb_Message_GetAttr(
+#if defined(__GNUC__) || defined(__clang__)
+__attribute__((flatten))
+#endif
+static PyObject* PyUpb_Message_GetAttr(
     PyObject* _self, PyObject* attr) {
   PyUpb_Message* self = (void*)_self;
 

python/protobuf.c

@@ -42,6 +42,8 @@
 typedef struct {
 #ifdef ENABLE_MUTEX
   pthread_mutex_t mutex;
+#else
+  char unused;
 #endif
 } FreeThreadingMutex;