fix(ci): avoid Metal wheel artifact collisions

Build one py3-none Metal wheel and download its artifact by name so two
macOS jobs cannot write different wheels to the same release path.
Verify the wheel ZIP before artifact upload and before release.

Assisted-by: OpenAI Codex
Signed-off-by: Haozhe Jiang <162801044+provoke210@users.noreply.github.com>

Author: provoke210

.github/workflows/build-wheels-metal.yaml

@@ -7,11 +7,10 @@ permissions:
 
 jobs:
   build_wheels:
-    name: Build wheels on ${{ matrix.os }}
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix:
-        os: [macos-14, macos-15]
+    # Two runners produced the same py3-none wheel filename, which collided
+    # when their artifacts were downloaded into one release directory.
+    name: Build wheels on macos-14
+    runs-on: macos-14
 
     steps:
       - uses: actions/checkout@v6
@@ -38,14 +37,18 @@ jobs:
           CIBW_REPAIR_WHEEL_COMMAND: ""
           CIBW_ARCHS: "arm64"
           CIBW_ENVIRONMENT: CMAKE_ARGS="-DCMAKE_OSX_ARCHITECTURES=arm64 -DCMAKE_APPLE_SILICON_PROCESSOR=arm64 -DGGML_METAL=on -DCMAKE_CROSSCOMPILING=ON"
-          CIBW_BUILD: "cp39-* cp310-* cp311-* cp312-*"
+          # wheel.py-api = py3 produces one wheel for all supported Python versions.
+          CIBW_BUILD: "cp39-*"
         with:
           package-dir: .
           output-dir: wheelhouse2
 
+      - name: Verify wheel archives
+        run: python3 scripts/verify-wheel-archives.py --expected-count 1 wheelhouse2/*.whl
+
       - uses: actions/upload-artifact@v7
         with:
-          name: wheels-mac_${{ matrix.os }}
+          name: wheels-mac_macos-14
           path: ./wheelhouse2/*.whl
 
   release:
@@ -54,11 +57,20 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/setup-python@v6
+        with:
+          python-version: "3.12"
+
       - uses: actions/download-artifact@v8
         with:
-          merge-multiple: true
+          name: wheels-mac_macos-14
           path: dist2
 
+      - name: Verify release wheel archives
+        run: python3 scripts/verify-wheel-archives.py --expected-count 1 dist2/*.whl
+
       - uses: softprops/action-gh-release@v3
         with:
           files: dist2/*

scripts/verify-wheel-archives.py

@@ -0,0 +1,40 @@
+"""Reject damaged wheel archives before uploading or publishing them."""
+
+import argparse
+import sys
+import zipfile
+from pathlib import Path
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--expected-count", type=int)
+    parser.add_argument("wheels", nargs="+")
+    args = parser.parse_args()
+
+    if args.expected_count is not None and len(args.wheels) != args.expected_count:
+        print(
+            f"Expected {args.expected_count} wheel archive(s), found {len(args.wheels)}",
+            file=sys.stderr,
+        )
+        return 1
+
+    failed = False
+    for name in args.wheels:
+        path = Path(name)
+        try:
+            with zipfile.ZipFile(path) as archive:
+                bad_file = archive.testzip()
+                if bad_file is not None:
+                    raise zipfile.BadZipFile(f"bad CRC in {bad_file}")
+        except (OSError, zipfile.BadZipFile) as exc:
+            print(f"Invalid wheel archive {path}: {exc}", file=sys.stderr)
+            failed = True
+        else:
+            print(f"Valid wheel archive: {path}")
+
+    return 1 if failed else 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())