feat: provide and use Python version support check

google/api_core/__init__.py

@@ -17,6 +17,18 @@
 This package contains common code and utilities used by Google client libraries.
 """
 
+from google.api_core import _python_package_support
+from google.api_core import _python_version_support
 from google.api_core import version as api_core_version
 
 __version__ = api_core_version.__version__
+
+# TODO: Until dependent artifacts require this version of
+# google.api_core, the functionality below must be made available
+# manually in those artifacts.
+
+check_python_version = _python_version_support.check_python_version
+check_python_version(package="google.api_core")
+
+check_dependency_versions = _python_package_support.check_dependency_versions
+check_dependency_versions("google.api_core")

google/api_core/_python_package_support.py

@@ -0,0 +1,153 @@
+# Copyright 2025 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.
+
+"""Code to check versions of dependencies used by Google Cloud Client Libraries."""
+
+import logging
+import sys
+from typing import Optional
+from ._python_version_support import (
+    _flatten_message,
+    _get_distribution_and_import_packages,
+)
+
+# It is a good practice to alias the Version class for clarity in type hints.
+from packaging.version import parse as parse_version, Version as PackagingVersion
+
+
+def get_dependency_version(dependency_name: str) -> Optional[PackagingVersion]:
+    """Get the parsed version of an installed package dependency.
+
+    This function checks for an installed package and returns its version
+    as a `packaging.version.Version` object for safe comparison. It handles
+    both modern (Python 3.8+) and legacy (Python 3.7) environments.
+
+    Args:
+        dependency_name: The distribution name of the package (e.g., 'requests').
+
+    Returns:
+        A `packaging.version.Version` object, or `None` if the package
+        is not found or another error occurs during version discovery.
+    """
+    try:
+        if sys.version_info >= (3, 8):
+            from importlib import metadata
+
+            version_string = metadata.version(dependency_name)
+            return parse_version(version_string)
+
+        # TODO: Remove this code path once we drop support for Python 3.7
+        else:
+            # Use pkg_resources, which is part of setuptools.
+            import pkg_resources
+
+            version_string = pkg_resources.get_distribution(dependency_name).version
+            return parse_version(version_string)
+
+    except Exception:
+        return None
+
+
+def warn_deprecation_for_versions_less_than(
+    dependent_import_package: str,
+    dependency_import_package: str,
+    next_supported_version: str,
+    message_template: Optional[str] = None,
+):
+    """Issue any needed deprecation warnings for `dependency_import_package`.
+
+    If `dependency_import_package` is installed at a version less than
+    `next_supported_versions`, this issues a warning using either a
+    default `message_template` or one provided by the user. The
+    default `message_template informs users that they will not receive
+    future updates `dependent_import_package` if
+    `dependency_import_package` is somehow pinned to a version lower
+    than `next_supported_version`.
+
+    Args:
+      dependent_import_package: The import name of the package that
+        needs `dependency_import_package`.
+      dependency_import_package: The import name of the dependency to check.
+      next_supported_version: The version number below which a deprecation
+        warning will be logged.
+      message_template: A custom default message template to replace
+        the default. This `message_template` is treated as an
+        f-string, where the following variables are defined:
+        `dependency_import_package`, `dependent_import_package`;
+        `dependency_packages` and `dependent_packages`, which contain both the
+         distribution and import packages for the dependency and the dependent,
+         respectively; and `next_supported_version`, and `version_used`, which
+         refer to supported and currently-used versions of the dependency.
+
+    """
+    if (
+        not dependent_import_package
+        or not dependency_import_package
+        or not next_supported_version
+    ):
+        return
+    version_used = get_dependency_version(dependency_import_package)
+    if not version_used:
+        return
+    if version_used < parse_version(next_supported_version):
+        (
+            dependency_packages,
+            dependency_distribution_package,
+        ) = _get_distribution_and_import_packages(dependency_import_package)
+        (
+            dependent_packages,
+            dependent_distribution_package,
+        ) = _get_distribution_and_import_packages(dependent_import_package)
+        message_template = message_template or _flatten_message(
+            """
+            DEPRECATION: Package {dependent_packages} depends on
+            {dependency_packages}, currently installed at version
+            {version_used.__str__}. Future updates to
+            {dependent_packages} will require {dependency_packages} at
+            version {next_supported_version} or higher. Please ensure
+            that either (a) your Python environment doesn't pin the
+            version of {dependency_packages}, so that updates to
+            {dependent_packages} can require the higher version, or
+            (b) you manually update your Python environment to use at
+            least version {next_supported_version} of
+            {dependency_packages}.
+            """
+        )
+        logging.warning(
+            message_template.format(
+                dependent_import_package=dependent_import_package,
+                dependency_import_package=dependency_import_package,
+                dependency_packages=dependency_packages,
+                dependent_packages=dependent_packages,
+                next_supported_version=next_supported_version,
+                version_used=version_used,
+            )
+        )
+
+
+def check_dependency_versions(dependent_import_package: str):
+    """Bundle checks for all package dependencies.
+
+    This function can be called by all dependents of google.api_core,
+    to emit needed deprecation warnings for any of their
+    dependencies. The dependencies to check should be updated here.
+
+    Args:
+      dependent_import_package: The distribution name of the calling package, whose
+        dependencies we're checking.
+
+    """
+    warn_deprecation_for_versions_less_than(
+        dependent_import_package, "google.protobuf", "4.25.8"
+    )