feat: Introduce compatibility with native namespace packages (#260)

* feat: Introduce compatibility with native namespace packages

* lint

* mypy

* omit /tmp/ in coverage

.coveragerc

@@ -3,6 +3,7 @@ branch = True
 
 [report]
 omit =
+    /tmp/*
     google/cloud/__init__.py
     google/cloud/_testing/__init__.py
     google/cloud/environment_vars/__init__.py

google/cloud/obsolete/__init__.py

@@ -14,9 +14,14 @@
 
 """Helpers for deprecated code and modules."""
 
+import sys
 import warnings
 
-import pkg_resources
+
+if sys.version_info < (3, 8):
+    import importlib_metadata as metadata
+else:
+    import importlib.metadata as metadata
 
 
 def complain(distribution_name):
@@ -29,7 +34,7 @@ def complain(distribution_name):
         distribution_name (str): The name of the obsolete distribution.
     """
     try:
-        pkg_resources.get_distribution(distribution_name)
+        metadata.distribution(distribution_name)
         warnings.warn(
             "The {pkg} distribution is now obsolete. "
             "Please `pip uninstall {pkg}`. "
@@ -38,5 +43,5 @@ def complain(distribution_name):
             ),
             DeprecationWarning,
         )
-    except pkg_resources.DistributionNotFound:
+    except metadata.PackageNotFoundError:
         pass

noxfile.py

@@ -48,7 +48,7 @@ def mypy(session):
         "types-mock",
         "types-protobuf",
     )
-    session.run("mypy", "google", "tests")
+    session.run("mypy", "-p", "google", "-p", "tests")
 
 
 @nox.session(python=DEFAULT_PYTHON_VERSION)

owlbot.py

@@ -35,7 +35,7 @@
         ".flake8",
         ".coveragerc",
         "setup.cfg",
-	"README.rst",
+        "README.rst",
     ],
 )
 

setup.py

@@ -30,6 +30,7 @@
 dependencies = [
     "google-api-core >= 1.31.6, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.0",
     "google-auth >= 1.25.0, < 3.0dev",
+    "importlib-metadata > 1.0.0; python_version<'3.8'",
 ]
 extras = {"grpc": "grpcio >= 1.38.0, < 2.0dev"}
 
@@ -50,15 +51,11 @@
 # Only include packages under the 'google' namespace. Do not include tests,
 # benchmarks, etc.
 packages = [
-    package for package in setuptools.find_packages() if package.startswith("google")
+    package
+    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,
@@ -83,7 +80,6 @@
     ],
     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 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-core``.
+    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-core``.
+    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)