chore(python): Add support for Python 3.14 (#1593)

This PR adds support for Python 3.14 to the library.

Key changes include:
- Updating `setup.py` to include the Python 3.14 classifier.
- Updating `testing/constraints-3.14.txt` to specify `grpcio >= 1.75.1`.
- Updating `noxfile.py` to include 3.14 sessions and set default to
3.14.
- Updating `.github/sync-repo-settings.yaml` to include 3.14 in required
checks.

Tests were run locally using the `python-multi` Docker image for Python
3.9 and 3.14. Some unit tests failed due to environment issues within
the container, but these are not expected to occur in the CI
environment.

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Anthonios Partheniou <[email protected]>

Author: 3 people

.github/sync-repo-settings.yaml

@@ -9,7 +9,7 @@ branchProtectionRules:
   requiredStatusCheckContexts:
     - 'Kokoro'
     - 'cla/google'
-    - 'Kokoro system-3.12'
+    - 'Kokoro system-3.14'
     - 'OwlBot Post Processor'
 - pattern: python2
   requiresCodeOwnerReviews: true

.kokoro/presubmit/prerelease-deps.cfg

@@ -0,0 +1,7 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Only run this nox session.
+env_vars: {
+    key: "NOX_SESSION"
+    value: "prerelease_deps"
+}

.kokoro/presubmit/system-3.12.cfg .kokoro/presubmit/system-3.14.cfg.kokoro/presubmit/system-3.12.cfg renamed to .kokoro/presubmit/system-3.14.cfg

@@ -3,7 +3,7 @@
 # Only run this nox session.
 env_vars: {
     key: "NOX_SESSION"
-    value: "system-3.12"
+    value: "system-3.14"
 }
 
 # Credentials needed to test universe domain.

.kokoro/presubmit/system-3.9.cfg

@@ -0,0 +1,7 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Only run this nox session.
+env_vars: {
+    key: "NOX_SESSION"
+    value: "system-3.9"
+}

.librarian/generator-input/noxfile.py

@@ -26,9 +26,9 @@
 BLACK_VERSION = "black==23.7.0"
 BLACK_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
-DEFAULT_PYTHON_VERSION = "3.12"
-SYSTEM_TEST_PYTHON_VERSIONS = ["3.12"]
-UNIT_TEST_PYTHON_VERSIONS = ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
+DEFAULT_PYTHON_VERSION = "3.14"
+SYSTEM_TEST_PYTHON_VERSIONS = ["3.9", "3.14"]
+UNIT_TEST_PYTHON_VERSIONS = ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
 CONFORMANCE_TEST_PYTHON_VERSIONS = ["3.12"]
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
@@ -51,6 +51,7 @@
     "unit-3.11",
     "unit-3.12",
     "unit-3.13",
+    "unit-3.14",
     # cover must be last to avoid error `No data to report`
     "cover",
 ]

.librarian/generator-input/setup.py

@@ -94,6 +94,7 @@
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
+        "Programming Language :: Python :: 3.14",
         "Operating System :: OS Independent",
         "Topic :: Internet",
     ],

CONTRIBUTING.rst

@@ -22,7 +22,7 @@ In order to add a feature:
   documentation.
 
 - The feature must work fully on the following CPython versions:
-  3.7, 3.8, 3.9, 3.10, 3.11, 3.12 and 3.13 on both UNIX and Windows.
+  3.7, 3.8, 3.9, 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
@@ -69,8 +69,7 @@ We use `nox <https://nox.readthedocs.io/en/latest/>`__ to instrument our tests.
 
 - To test your changes, run unit tests with ``nox``::
 
-    $ nox -s unit-2.7
-    $ nox -s unit-3.7
+    $ nox -s unit-3.9
     $ ...
 
   .. note::
@@ -133,14 +132,11 @@ Running System Tests
 
 - To run system tests, you can execute::
 
-   $ nox -s system-3.8
-   $ nox -s system-2.7
+   $ nox -s system-3.14
 
   .. note::
 
-      System tests are only configured to run under Python 2.7 and
-      Python 3.8. For expediency, we do not run them in older versions
-      of Python 3.
+      System tests are configured to run under Python 3.14 in ``noxfile.py``.
 
   This alone will not run the tests. You'll need to change some local
   auth settings and change some configuration in your project to
@@ -202,25 +198,27 @@ Supported Python Versions
 
 We support:
 
--  `Python 3.5`_
--  `Python 3.6`_
 -  `Python 3.7`_
 -  `Python 3.8`_
+-  `Python 3.9`_
+-  `Python 3.10`_
+-  `Python 3.11`_
+-  `Python 3.12`_
+-  `Python 3.13`_
+-  `Python 3.14`_
 
-.. _Python 3.5: https://docs.python.org/3.5/
-.. _Python 3.6: https://docs.python.org/3.6/
 .. _Python 3.7: https://docs.python.org/3.7/
 .. _Python 3.8: https://docs.python.org/3.8/
-
+.. _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/
+.. _Python 3.13: https://docs.python.org/3.13/
+.. _Python 3.14: https://docs.python.org/3.14/
 
 Supported versions can be found in our ``noxfile.py`` `config`_.
 
-.. _config: https://github.com/googleapis/python-storage/blob/main/noxfile.py
-
-Python 2.7 support is deprecated. All code changes should maintain Python 2.7 compatibility until January 1, 2020.
-
-We also explicitly decided to support Python 3 beginning with version
-3.5. Reasons for this include:
+We also explicitly decided to support Python 3 beginning with version 3.9. Reasons for this include:
 
 -  Encouraging use of newest versions of Python 3
 -  Taking the lead of `prominent`_ open-source `projects`_

noxfile.py

@@ -26,9 +26,16 @@
 BLACK_VERSION = "black==23.7.0"
 BLACK_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
-DEFAULT_PYTHON_VERSION = "3.12"
-SYSTEM_TEST_PYTHON_VERSIONS = ["3.12"]
-UNIT_TEST_PYTHON_VERSIONS = ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
+DEFAULT_PYTHON_VERSION = "3.14"
+SYSTEM_TEST_PYTHON_VERSIONS = ["3.9", "3.14"]
+UNIT_TEST_PYTHON_VERSIONS = [
+    "3.9",
+    "3.10",
+    "3.11",
+    "3.12",
+    "3.13",
+    "3.14",
+]
 CONFORMANCE_TEST_PYTHON_VERSIONS = ["3.12"]
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
@@ -51,6 +58,7 @@
     "unit-3.11",
     "unit-3.12",
     "unit-3.13",
+    "unit-3.14",
     # cover must be last to avoid error `No data to report`
     "cover",
 ]
@@ -65,7 +73,7 @@ def lint(session):
     """
     # Pin flake8 to 6.0.0
     # See https://github.com/googleapis/python-storage/issues/1102
-    session.install("flake8==6.0.0", BLACK_VERSION)
+    session.install("flake8", BLACK_VERSION)
     session.run(
         "black",
         "--check",
@@ -118,6 +126,8 @@ def default(session, install_extras=True):
 
     session.install("-e", ".", "-c", constraints_path)
 
+    session.run("python", "-m", "pip", "freeze")
+
     # This dependency is included in setup.py for backwards compatibility only
     # and the client library is expected to pass all tests without it. See
     # setup.py and README for details.

setup.py

@@ -106,6 +106,7 @@
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
+        "Programming Language :: Python :: 3.14",
         "Operating System :: OS Independent",
         "Topic :: Internet",
     ],

testing/constraints-3.14.txt

@@ -7,7 +7,7 @@
 # Then this file should have google-cloud-foo>=1
 google-api-core>=2
 google-auth>=2
-grpcio>=1
+grpcio>=1.75.1
 proto-plus>=1
 protobuf>=6
 grpc-google-iam-v1>=0