PYTHON-5839 - PyMongo wheels have multiple versions of C extensions

.github/workflows/dist.yml

@@ -78,6 +78,9 @@ jobs:
       - name: Build wheels
         env:
           CIBW_BUILD: ${{ matrix.buildplat[2] }}
+          # Strip any in-place C extensions from previous builds
+          # so they don't leak into the next wheel.
+          CIBW_BEFORE_BUILD: python ./tools/clean.py
         run: python -m cibuildwheel --output-dir wheelhouse
 
       - name: Assert all versions in wheelhouse

tools/clean.py

@@ -1,4 +1,4 @@
-# Copyright 2009-2015 MongoDB, Inc.
+# Copyright 2009-present MongoDB, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -12,37 +12,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""Clean up script for build artifacts.
+"""Remove built C extensions from the source tree.
 
-Only really intended to be used by internal build scripts.
+Used as cibuildwheel's before-build hook so artifacts from one Python
+version do not leak into the wheel built for the next.
 """
 from __future__ import annotations
 
-import sys
 from pathlib import Path
 
-try:
-    Path("pymongo/_cmessage.so").unlink()
-    Path("bson/_cbson.so").unlink()
-except BaseException:  # noqa: S110
-    pass
-
-try:
-    Path("pymongo/_cmessage.pyd").unlink()
-    Path("bson/_cbson.pyd").unlink()
-except BaseException:  # noqa: S110
-    pass
-
-try:
-    from pymongo import _cmessage  # type: ignore[attr-defined]  # noqa: F401
-
-    sys.exit("could still import _cmessage")
-except ImportError:
-    pass
-
-try:
-    from bson import _cbson  # type: ignore[attr-defined] # noqa: F401
-
-    sys.exit("could still import _cbson")
-except ImportError:
-    pass
+for pkg in ("bson", "pymongo"):
+    for pattern in ("*.so", "*.pyd"):
+        for path in Path(pkg).glob(pattern):
+            path.unlink()
+            print(f"removed {path}")