feat: Introduce compatibility with native namespace packages

setup.py

@@ -28,6 +28,12 @@
     assert len(version_candidates) == 1
     version = version_candidates[0]
 
+packages = [
+    package
+    for package in setuptools.find_namespace_packages()
+    if package.startswith("google")
+]
+
 def main():
     package_root = os.path.abspath(os.path.dirname(__file__))
     readme_filename = os.path.join(package_root, "README.md")
@@ -73,8 +79,7 @@ def main():
             "Topic :: Internet",
         ],
         platforms="Posix; MacOS X; Windows",
-        packages=setuptools.find_packages(),
-        namespace_packages=["google", "google.cloud"],
+        packages=packages,
         install_requires=dependencies,
         extras_require={},
         python_requires=">=3.7",

tests/unit/test_packaging.py

@@ -0,0 +1,37 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import subprocess
+import sys
+
+
+def test_namespace_package_compat(tmp_path):
+    # The ``google`` namespace package should not be masked
+    # by the presence of ``google-cloud-ndb``.
+    google = tmp_path / "google"
+    google.mkdir()
+    google.joinpath("othermod.py").write_text("")
+    env = dict(os.environ, PYTHONPATH=str(tmp_path))
+    cmd = [sys.executable, "-m", "google.othermod"]
+    subprocess.check_call(cmd, env=env)
+
+    # The ``google.cloud`` namespace package should not be masked
+    # by the presence of ``google-cloud-ndb``.
+    google_cloud = tmp_path / "google" / "cloud"
+    google_cloud.mkdir()
+    google_cloud.joinpath("othermod.py").write_text("")
+    env = dict(os.environ, PYTHONPATH=str(tmp_path))
+    cmd = [sys.executable, "-m", "google.cloud.othermod"]
+    subprocess.check_call(cmd, env=env)