feat: Introduce compatibility with native namespace packages

.coveragerc

@@ -12,8 +12,3 @@ exclude_lines =
     pragma: NO COVER
     # Ignore debug-only repr
     def __repr__
-    # Ignore pkg_resources exceptions.
-    # This is added at the module level as a safeguard for if someone
-    # generates the code and tries to run it without pip installing. This
-    # makes it virtually impossible to test properly.
-    except pkg_resources.DistributionNotFound

noxfile.py

@@ -137,7 +137,7 @@ def mypy(session):
         "types-requests",
         "types-setuptools",
     )
-    session.run("mypy", "google/cloud", "--show-traceback")
+    session.run("mypy", "-p", "google", "--show-traceback")
 
 
 @nox.session(python=DEFAULT_PYTHON_VERSION)
@@ -149,7 +149,8 @@ def pytype(session):
     session.install("attrs==20.3.0")
     session.install("-e", ".[all]")
     session.install(PYTYPE_VERSION)
-    session.run("pytype")
+    # See https://github.com/google/pytype/issues/464
+    session.run("pytype", "-P", ".", "google/cloud/bigquery")
 
 
 @nox.session(python=SYSTEM_TEST_PYTHON_VERSIONS)

setup.py

@@ -108,16 +108,10 @@
 # benchmarks, etc.
 packages = [
     package
-    for package in setuptools.PEP420PackageFinder.find()
+    for package in setuptools.find_namespace_packages()
     if package.startswith("google")
 ]
 
-# Determine which namespaces are needed.
-namespaces = ["google"]
-if "google.cloud" in packages:
-    namespaces.append("google.cloud")
-
-
 setuptools.setup(
     name=name,
     version=version,
@@ -143,7 +137,6 @@
     ],
     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-bigquery``.
+    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-bigquery``.
+    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)