fix(documentai-toolbox): Drop support for Python <= 3.9 (#16967)

This PR updates `google-cloud-documentai-toolbox` to establish Python
3.10 as the minimum supported version, dropping support for Python 3.9
and below.

### Changes
* **Configuration**: Updated `setup.py` and `noxfile.py` to require
Python 3.10+ and remove references to Python 3.9. Deleted
`constraints-3.9.txt`.
* **Documentation**: Updated `README.rst` and `CONTRIBUTING.rst` to
require Python 3.10+ and remove references to Python 3.9. Synced the
top-level `README.rst` to the `docs` folder.
* **Cleanup**: Removed obsolete warning suppressions in `pytest.ini`
related to Python 3.7 and 3.8. Updated the runtime version check in
`__init__.py` to warn on versions older than 3.10.
* **Dependency Fixes**: Resolved dependency conflicts on Python 3.10 by
bumping the minimum version of `google-cloud-storage` to `2.0.0` in
`setup.py` to avoid conflicts with `google-auth`. Added
`setuptools==79.0.0` to `constraints-3.10.txt` to resolve the
`ModuleNotFoundError: No module named 'pkg_resources'` and avoid its
subsequent deprecation warning.

Fixes internal issue: http://b/482126936 🦕

Author: chalmerlowe

packages/google-cloud-documentai-toolbox/CONTRIBUTING.rst

@@ -22,7 +22,7 @@ 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
@@ -148,8 +148,6 @@ Running System Tests
 
   .. note::
 
-      System tests are only configured to run under Python 3.9 and 3.14.
-      For expediency, we do not run them in older versions of Python 3.
 
   This alone will not run the tests. You'll need to change some local
   auth settings and change some configuration in your project to
@@ -197,14 +195,12 @@ 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/
@@ -217,17 +213,7 @@ Supported versions can be found in our ``noxfile.py`` `config`_.
 .. _config: https://github.com/googleapis/google-cloud-python/blob/main/packages/google-cloud-documentai-toolbox/noxfile.py
 
 
-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`_
--  `Unicode literal support`_ which allows for a cleaner codebase that
-   works in both Python 2 and Python 3
-
-.. _prominent: https://docs.djangoproject.com/en/1.9/faq/install/#what-python-version-can-i-use-with-django
-.. _projects: http://flask.pocoo.org/docs/0.10/python3/
-.. _Unicode literal support: https://www.python.org/dev/peps/pep-0414/
 
 **********
 Versioning

packages/google-cloud-documentai-toolbox/README.rst

@@ -63,14 +63,14 @@ Supported Python Versions
 Our client libraries are compatible with all current `active`_ and `maintenance`_ versions of
 Python.
 
-Python >= 3.9
+Python >= 3.10
 
 .. _active: https://devguide.python.org/devcycle/#in-development-main-branch
 .. _maintenance: https://devguide.python.org/devcycle/#maintenance-branches
 
 Unsupported Python Versions
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Python <= 3.8
+Python <= 3.9
 
 If you are using an `end-of-life`_
 version of Python, we recommend that you update as soon as possible to an actively supported version.

packages/google-cloud-documentai-toolbox/docs/README.rst

@@ -63,14 +63,14 @@ Supported Python Versions
 Our client libraries are compatible with all current `active`_ and `maintenance`_ versions of
 Python.
 
-Python >= 3.9
+Python >= 3.10
 
 .. _active: https://devguide.python.org/devcycle/#in-development-main-branch
 .. _maintenance: https://devguide.python.org/devcycle/#maintenance-branches
 
 Unsupported Python Versions
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Python <= 3.8
+Python <= 3.9
 
 If you are using an `end-of-life`_
 version of Python, we recommend that you update as soon as possible to an actively supported version.

packages/google-cloud-documentai-toolbox/google/cloud/documentai_toolbox/__init__.py

@@ -35,17 +35,11 @@
 )
 
 
-class Python37DeprecationWarning(DeprecationWarning):  # pragma: NO COVER
-    """
-    Deprecation warning raised when Python 3.7 runtime is detected.
-    Python 3.7 support will be dropped after January 1, 2024.
-    """
-
-
-# Checks if the current runtime is Python 3.7.
-if sys.version_info.major == 3 and sys.version_info.minor == 7:  # pragma: NO COVER
+# Checks if the current runtime is Python < 3.10.
+if sys.version_info < (3, 10):  # pragma: NO COVER
     message = (
-        "After January 1, 2024, new releases of this library will drop support "
-        "for Python 3.7."
+        "The google-cloud-documentai-toolbox library no longer supports Python 3.7, 3.8, and 3.9. "
+        "We recommend that you update soon to ensure ongoing support. For "
+        "more details, see: [Google Cloud Client Libraries Supported Python Versions policy](https://cloud.google.com/python/docs/supported-python-versions)"
     )
-    warnings.warn(message, Python37DeprecationWarning)
+    warnings.warn(message, FutureWarning)

packages/google-cloud-documentai-toolbox/noxfile.py

@@ -36,7 +36,6 @@
 DEFAULT_PYTHON_VERSION = "3.14"
 
 UNIT_TEST_PYTHON_VERSIONS: List[str] = [
-    "3.9",
     "3.10",
     "3.11",
     "3.12",
@@ -57,7 +56,7 @@
 UNIT_TEST_EXTRAS: List[str] = []
 UNIT_TEST_EXTRAS_BY_PYTHON: Dict[str, List[str]] = {}
 
-SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ["3.9", "3.14"]
+SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ["3.12"]
 SYSTEM_TEST_STANDARD_DEPENDENCIES: List[str] = [
     "mock",
     "pytest",
@@ -72,7 +71,6 @@
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 
 nox.options.sessions = [
-    "unit-3.9",
     "unit-3.10",
     "unit-3.11",
     "unit-3.12",

packages/google-cloud-documentai-toolbox/pytest.ini

@@ -6,15 +6,11 @@ filterwarnings =
     ignore:.*custom tp_new.*in Python 3.14:DeprecationWarning
     # Remove once https://github.com/dateutil/dateutil/issues/1314 is fixed
     ignore:datetime.datetime.utcfromtimestamp\(\) is deprecated:DeprecationWarning:dateutil.tz.tz
-    # Remove once Python3.7 support is dropped https://github.com/googleapis/python-documentai-toolbox/issues/209
-    ignore:distutils Version classes are deprecated:DeprecationWarning
-    # Remove after support for Python 3.7 is dropped
-    ignore:After January 1, 2024, new releases of this library will drop support for Python 3.7:DeprecationWarning
+
     # Remove once the minimum supported version of `google-api-core` is 2.15.0
     ignore:.*pkg_resources.declare_namespace:DeprecationWarning
     ignore:.*pkg_resources is deprecated as an API:DeprecationWarning
-    # Remove once the minimum supported Python runtime of this library is Python 3.9
-    ignore:The python-bigquery library will stop supporting Python 3.7 and Python 3.8:PendingDeprecationWarning
+
     # This error is expected for python versions that approach EOL
     ignore:.*Please upgrade to the latest Python version.*:FutureWarning
     ignore:(?s).*using a Python version.*past its end of life.*:FutureWarning

packages/google-cloud-documentai-toolbox/setup.py

@@ -62,21 +62,20 @@
         "grpc-google-iam-v1>=0.12.6, <1.0.0",
         "google-cloud-bigquery>=3.14.0, <4.0.0",
         "google-cloud-documentai>=2.29.2, <4.0.0",
-        "google-cloud-storage>=1.31.0, <4.0.0",
-        "google-cloud-vision>=2.7.0, <4.0.0",
+        "google-cloud-storage>=2.3.0, <4.0.0",
+        "google-cloud-vision>=3.2.0, <4.0.0",
         "numpy>=1.23.5, <3.0.0",
         "intervaltree>=3.0.0",
         "pikepdf>=8.0.0, <11.0.0",
         "immutabledict>=2.0.0, <5.0.0",
         "Pillow>=10.0.0, <12.0.0",
         "Jinja2>=3.1.0, <4.0.0",
     ),
-    python_requires=">=3.9",
+    python_requires=">=3.10",
     classifiers=[
         "Development Status :: 3 - Alpha",
         "Intended Audience :: Developers",
         "Operating System :: OS Independent",
-        "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",

packages/google-cloud-documentai-toolbox/testing/constraints-3.10.txt

@@ -1,12 +1,22 @@
-# -*- coding: utf-8 -*-
-# This constraints file is required for unit tests.
-# List all library dependencies and extras in this file.
-google-api-core
-pandas
-proto-plus
-grpc-google-iam-v1
-google-cloud-bigquery
-google-cloud-documentai
-google-cloud-storage
-numpy
-pikepdf
+# This constraints file is used to check that lower bounds
+# are correct in setup.py
+# List all library dependencies and extras in this file,
+# pinning their versions to their lower bounds.
+# For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
+# then this file should have google-cloud-foo==1.14.0
+google-api-core==2.15.0
+pandas==2.0.0
+pyarrow==15.0.0
+tabulate==0.9.0
+proto-plus==1.22.3
+grpc-google-iam-v1==0.12.6
+google-cloud-bigquery==3.14.0
+google-cloud-documentai==2.29.2
+google-cloud-storage==2.3.0
+google-cloud-vision==3.2.0
+numpy==1.23.5
+intervaltree==3.0.0
+pikepdf==8.0.0
+immutabledict==2.0.0
+Pillow==10.0.0
+Jinja2==3.1.0