fix(api-core): drop support for Python 3.9 (#16980)

This PR updates google-api-core to establish Python 3.10 as the minimum
supported version, dropping support for Python 3.9 and below.

### Changes
**Configuration**: Updated pyproject.toml and noxfile.py to require
Python 3.10+ and remove references to Python 3.7, 3.8, and 3.9. Updated
README.rst and CONTRIBUTING.rst to reflect the new support status.
**Cleanup**: Removed aiter and anext polyfills in test_bidi_async.py and
removed Python < 3.10 polyfills in _python_version_support.py.
**Constraints & Dependencies**:
* Created constraints-3.10.txt using the old 3.9 constraints as a
baseline.
* Bumped grpcio to 1.80.0 and requests to 2.33.0 to avoid issues with
pkg_resources and six warnings on Python 3.10.
* Bumped google-auth to 2.35.0 to satisfy async_rest requirements.
Fixes internal issue: http://b/482126936 🦕

Author: chalmerlowe

packages/google-api-core/CONTRIBUTING.rst

@@ -21,7 +21,7 @@ In order to add a feature:
   documentation.
 
 - The feature must work fully on the following CPython versions:
-  3.9, 3.10, 3.11, 3.12, 3.13 and 3.14 on both UNIX and Windows.
+  3.10, 3.11, 3.12, 3.13 and 3.14 on both UNIX and Windows.
 
 - The feature must not add unnecessary dependencies (where
   "unnecessary" is of course subjective, but new dependencies should
@@ -171,11 +171,11 @@ configure them just like the System Tests.
 
    # Run all tests in a folder
    $ cd samples/snippets
-   $ nox -s py-3.8
+   $ nox -s py-3.10
 
    # Run a single sample test
    $ cd samples/snippets
-   $ nox -s py-3.8 -- -k <name of test>
+   $ nox -s py-3.10 -- -k <name of test>
 
 ********************************************
 Note About ``README`` as it pertains to PyPI
@@ -197,14 +197,12 @@ Supported Python Versions
 
 We support:
 
--  `Python 3.9`_
 -  `Python 3.10`_
 -  `Python 3.11`_
 -  `Python 3.12`_
 -  `Python 3.13`_
 -  `Python 3.14`_
 
-.. _Python 3.9: https://docs.python.org/3.9/
 .. _Python 3.10: https://docs.python.org/3.10/
 .. _Python 3.11: https://docs.python.org/3.11/
 .. _Python 3.12: https://docs.python.org/3.12/

packages/google-api-core/README.rst

@@ -16,13 +16,12 @@ common helpers used by all Google API clients. For more information, see the
 
 Supported Python Versions
 -------------------------
-Python >= 3.9
+Python >= 3.10
 
 
 Unsupported Python Versions
 ---------------------------
-
-Python == 2.7, Python == 3.5, Python == 3.6, Python == 3.7, Python == 3.8.
+Python <= 3.9
 
 The last version of this library compatible with Python 2.7 and 3.5 is
 `google-api-core==1.31.1`.
@@ -32,3 +31,6 @@ The last version of this library compatible with Python 3.6 is
 
 The last version of this library compatible with Python 3.7 and 3.8 is
 `google-api-core==2.29.0`.
+
+The last version of this library compatible with Python 3.9 is
+`google-api-core==2.30.3`.

packages/google-api-core/google/api_core/_python_version_support.py

@@ -17,6 +17,7 @@
 import datetime
 import enum
 import functools
+from importlib import metadata
 import logging
 import warnings
 import sys
@@ -71,13 +72,6 @@ class VersionInfo(NamedTuple):
 
 PYTHON_VERSIONS: List[VersionInfo] = [
     # Refer to https://devguide.python.org/versions/ and the PEPs linked therefrom.
-    VersionInfo(
-        version="3.9",
-        python_beta=datetime.date(2020, 5, 18),
-        python_start=datetime.date(2020, 10, 5),
-        python_eol=datetime.date(2025, 10, 5),
-        gapic_end=datetime.date(2025, 10, 5) + datetime.timedelta(days=90),
-    ),
     VersionInfo(
         version="3.10",
         python_beta=datetime.date(2021, 5, 3),
@@ -140,38 +134,26 @@ def _flatten_message(text: str) -> str:
     return " ".join(textwrap.dedent(text).strip().split())
 
 
-# TODO(https://github.com/googleapis/python-api-core/issues/835):
-# Remove once we no longer support Python 3.9.
-# `importlib.metadata.packages_distributions()` is only supported in Python 3.10 and newer
-# https://docs.python.org/3/library/importlib.metadata.html#importlib.metadata.packages_distributions
-if sys.version_info < (3, 10):
-
-    def _get_pypi_package_name(module_name):  # pragma: NO COVER
-        """Determine the PyPI package name for a given module name."""
-        return None
+@functools.cache
+def _cached_packages_distributions():
+    return metadata.packages_distributions()
 
-else:
-    from importlib import metadata
 
-    @functools.cache
-    def _cached_packages_distributions():
-        return metadata.packages_distributions()
+def _get_pypi_package_name(module_name):
+    """Determine the PyPI package name for a given module name."""
+    try:
+        module_to_distributions = _cached_packages_distributions()
 
-    def _get_pypi_package_name(module_name):
-        """Determine the PyPI package name for a given module name."""
-        try:
-            module_to_distributions = _cached_packages_distributions()
-
-            if module_name in module_to_distributions:  # pragma: NO COVER
-                return module_to_distributions[module_name][0]
-        except Exception as e:  # pragma: NO COVER
-            _LOGGER.info(
-                "An error occurred while determining PyPI package name for %s: %s",
-                module_name,
-                e,
-            )
+        if module_name in module_to_distributions:  # pragma: NO COVER
+            return module_to_distributions[module_name][0]
+    except Exception as e:  # pragma: NO COVER
+        _LOGGER.info(
+            "An error occurred while determining PyPI package name for %s: %s",
+            module_name,
+            e,
+        )
 
-        return None
+    return None
 
 
 def _get_distribution_and_import_packages(import_package: str) -> Tuple[str, Any]:

packages/google-api-core/google/api_core/client_info.py

@@ -45,7 +45,7 @@ class ClientInfo(object):
 
     Args:
         python_version (str): The Python interpreter version, for example,
-            ``'3.9.6'``.
+            ``'3.10.0'``.
         grpc_version (Optional[str]): The gRPC library version.
         api_core_version (str): The google-api-core library version.
         gapic_version (Optional[str]): The version of gapic-generated client

packages/google-api-core/google/api_core/gapic_v1/client_info.py

@@ -33,7 +33,7 @@ class ClientInfo(client_info.ClientInfo):
 
     Args:
         python_version (str): The Python interpreter version, for example,
-            ``'3.9.6'``.
+            ``'3.10.0'``.
         grpc_version (Optional[str]): The gRPC library version.
         api_core_version (str): The google-api-core library version.
         gapic_version (Optional[str]): The version of gapic-generated client

packages/google-api-core/google/api_core/grpc_helpers_async.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""AsyncIO helpers for :mod:`grpc` supporting 3.7+.
+"""AsyncIO helpers for :mod:`grpc`.
 
 Please combine more detailed docstring in grpc_helpers.py to use following
 functions. This module is implementing the same surface with AsyncIO semantics.

packages/google-api-core/noxfile.py

@@ -14,7 +14,7 @@
 
 # Helpful notes for local usage:
 #   unset PYENV_VERSION
-#   pyenv local 3.14.1 3.13.10 3.12.11 3.11.4 3.10.12 3.9.17
+#   pyenv local 3.14.1 3.13.10 3.12.11 3.11.4 3.10.12
 #   PIP_INDEX_URL=https://pypi.org/simple nox
 
 from __future__ import absolute_import
@@ -34,8 +34,8 @@
 # Black and flake8 clash on the syntax for ignoring flake8's F401 in this file.
 BLACK_EXCLUDES = ["--exclude", "^/google/api_core/operations_v1/__init__.py"]
 
-ALL_PYTHON = ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
-SUPPORTED_PYTHON_VERSIONS = ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
+ALL_PYTHON = ["3.10", "3.11", "3.12", "3.13", "3.14"]
+SUPPORTED_PYTHON_VERSIONS = ["3.10", "3.11", "3.12", "3.13", "3.14"]
 
 DEFAULT_PYTHON_VERSION = "3.14"
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
@@ -303,7 +303,7 @@ def default(
         (
             True,
             False,
-            ["3.9", "3.10", "3.11"],
+            ["3.10", "3.11"],
             4,
         ),  # Run proto4 tests with grpcio/grpcio-gcp installed
     ],
@@ -325,13 +325,13 @@ def unit(
         session.log(f"Skipping session for Python {session.python}")
         session.skip()
 
-    # TODO: consider converting the following into a `match` statement once
-    # we drop Python 3.9 support.
-    if legacy_proto:
-        if legacy_proto == 4:
+    match legacy_proto:
+        case 4:
             # Pin protobuf to a 4.x version to ensure coverage for the legacy code path.
             session.install("protobuf>=4.25.8,<5.0.0")
-        else:
+        case None | False:
+            pass
+        case _:
             assert False, f"Unknown legacy_proto: {legacy_proto}"
 
     default(

packages/google-api-core/pyproject.toml

@@ -20,7 +20,7 @@ build-backend = "setuptools.build_meta"
 name = "google-api-core"
 authors = [{ name = "Google LLC", email = "googleapis-packages@google.com" }]
 license = { text = "Apache 2.0" }
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 readme = "README.rst"
 description = "Google API client core library"
 classifiers = [
@@ -34,7 +34,6 @@ classifiers = [
   "Programming Language :: Python",
   "Programming Language :: Python :: 3",
 
-  "Programming Language :: Python :: 3.9",
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
@@ -49,7 +48,7 @@ dependencies = [
   "proto-plus >= 1.22.3, < 2.0.0",
   "proto-plus >= 1.25.0, < 2.0.0; python_version >= '3.13'",
   "google-auth >= 2.14.1, < 3.0.0",
-  "requests >= 2.20.0, < 3.0.0",
+  "requests >= 2.25.0, < 3.0.0",
 ]
 dynamic = ["version"]
 
@@ -59,12 +58,12 @@ Documentation = "https://googleapis.dev/python/google-api-core/latest/"
 Repository = "https://github.com/googleapis/google-cloud-python"
 
 [project.optional-dependencies]
-async_rest = ["google-auth[aiohttp] >= 2.35.0, < 3.0.0"]
+async_rest = ["google-auth[aiohttp] >= 2.14.1, < 3.0.0", "aiohttp >= 3.9.0"]
 grpc = [
-  "grpcio >= 1.33.2, < 2.0.0",
+  "grpcio >= 1.41.0, < 2.0.0",
   "grpcio >= 1.49.1, < 2.0.0; python_version >= '3.11'",
   "grpcio >= 1.75.1, < 2.0.0; python_version >= '3.14'",
-  "grpcio-status >= 1.33.2, < 2.0.0",
+  "grpcio-status >= 1.41.0, < 2.0.0",
   "grpcio-status >= 1.49.1, < 2.0.0; python_version >= '3.11'",
   "grpcio-status >= 1.75.1, < 2.0.0; python_version >= '3.14'",
 ]

packages/google-api-core/testing/constraints-3.10.txt

@@ -0,0 +1,14 @@
+# This constraints file is used to check that lower bounds
+# are correct in pyproject.toml
+# List *all* library dependencies and extras in this file.
+# Pin the version to the lower bound.
+#
+# e.g., if pyproject.toml has "foo >= 1.14.0, < 2.0.0dev",
+# Then this file should have foo==1.14.0
+googleapis-common-protos==1.63.2
+protobuf==4.25.8
+google-auth==2.14.1
+requests==2.25.0
+grpcio==1.41.0
+grpcio-status==1.41.0
+proto-plus==1.22.3

…gle-api-core/testing/constraints-3.9.txt …/testing/constraints-async-rest-3.10.txtpackages/google-api-core/testing/constraints-3.9.txt renamed to packages/google-api-core/testing/constraints-async-rest-3.10.txt packages/google-api-core/testing/constraints-3.9.txt renamed to packages/google-api-core/testing/constraints-async-rest-3.10.txt

@@ -8,7 +8,12 @@
 googleapis-common-protos==1.63.2
 protobuf==4.25.8
 google-auth==2.14.1
-requests==2.20.0
-grpcio==1.33.2
-grpcio-status==1.33.2
+requests==2.25.0
+grpcio==1.41.0
+grpcio-status==1.41.0
 proto-plus==1.22.3
+# Note: We pin aiohttp to 3.9.0 to avoid deprecation warnings about '@coroutine'
+# decorators which were deprecated since Python 3.8. When older versions of aiohttp
+# load, because they used @coroutine deep inside their internals, the warnings
+# bubble up and cause our nox session to fail.
+aiohttp==3.9.0