feat: Introduce compatibility with native namespace packages

.coveragerc

@@ -17,6 +17,9 @@
 # Generated by synthtool. DO NOT EDIT!
 [run]
 branch = True
+omit =
+  /tmp/*
+  .nox/*
 
 [report]
 fail_under = 100
@@ -29,7 +32,9 @@ exclude_lines =
     # Ignore abstract methods
     raise NotImplementedError
 omit =
+  /tmp/*
+  .nox/*
   */gapic/*.py
   */proto/*.py
   */core/*.py
-  */site-packages/*.py
+  */site-packages/*.py

noxfile.py

@@ -173,9 +173,9 @@ def default(session):
     session.run(
         "py.test",
         "--quiet",
-        "--cov=google.cloud.spanner",
-        "--cov=google.cloud",
-        "--cov=tests.unit",
+        f"--junitxml=unit_{session.python}_sponge_log.xml",
+        "--cov=google",
+        "--cov=tests/unit",
         "--cov-append",
         "--cov-config=.coveragerc",
         "--cov-report=",

owlbot.py

@@ -222,16 +222,6 @@ def place_before(path, text, *before_text, escape=None):
     escape="()",
 )
 
-s.replace(
-    "noxfile.py",
-    """f"--junitxml=unit_{session.python}_sponge_log.xml",
-        "--cov=google",
-        "--cov=tests/unit",""",
-    """\"--cov=google.cloud.spanner",
-        "--cov=google.cloud",
-        "--cov=tests.unit",""",
-)
-
 s.replace(
     "noxfile.py",
     r"""session.install\("-e", "."\)""",

setup.py

@@ -63,14 +63,10 @@
 
 packages = [
     package
-    for package in setuptools.PEP420PackageFinder.find()
+    for package in setuptools.find_namespace_packages()
     if package.startswith("google")
 ]
 
-namespaces = ["google"]
-if "google.cloud" in packages:
-    namespaces.append("google.cloud")
-
 setuptools.setup(
     name=name,
     version=version,
@@ -97,7 +93,6 @@
     ],
     platforms="Posix; MacOS X; Windows",
     packages=packages,
-    namespace_packages=namespaces,
     install_requires=dependencies,
     extras_require=extras,
     python_requires=">=3.7",

tests/unit/test_packaging.py

@@ -0,0 +1,37 @@
+# Copyright 2022 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-spanner``.
+    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-spanner``.
+    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)