Replace utcnow() which is deprecated on Python 3.13

[jenstroeger]

Describe the bug

This use of utcnow()

alembic/alembic/script/base.py

Lines 631 to 635 in 41198bb

	create_date = (
	datetime.datetime.utcnow()
	.replace(tzinfo=datetime.timezone.utc)
	.astimezone(tzinfo)
	)

fails Alembic:

Traceback (most recent call last):
  File "/path/to/.venv/bin/alembic", line 8, in <module>
    sys.exit(main())
             ~~~~^^
  File "/path/to/.venv/lib/python3.13/site-packages/alembic/config.py", line 636, in main
    CommandLine(prog=prog).main(argv=argv)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/path/to/.venv/lib/python3.13/site-packages/alembic/config.py", line 626, in main
    self.run_cmd(cfg, options)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/path/to/.venv/lib/python3.13/site-packages/alembic/config.py", line 603, in run_cmd
    fn(
    ~~^
        config,
        ^^^^^^^
        *[getattr(options, k, None) for k in positional],
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        **{k: getattr(options, k, None) for k in kwarg},
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/path/to/.venv/lib/python3.13/site-packages/alembic/command.py", line 243, in revision
    scripts = [script for script in revision_context.generate_scripts()]
                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/path/to/.venv/lib/python3.13/site-packages/alembic/autogenerate/api.py", line 650, in generate_scripts
    yield self._to_script(generated_revision)
          ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
  File "/path/to/.venv/lib/python3.13/site-packages/alembic/autogenerate/api.py", line 555, in _to_script
    return self.script_directory.generate_revision(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        migration_script.rev_id,
        ^^^^^^^^^^^^^^^^^^^^^^^^
    ...<7 lines>...
        **template_args,
        ^^^^^^^^^^^^^^^^
    )
    ^
  File "/path/to/.venv/lib/python3.13/site-packages/alembic/script/base.py", line 693, in generate_revision
    create_date = self._generate_create_date()
  File "/path/to/.venv/lib/python3.13/site-packages/alembic/script/base.py", line 632, in _generate_create_date
    datetime.datetime.utcnow()
    ~~~~~~~~~~~~~~~~~~~~~~~~^^
DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).

Expected behavior

Alembic should succeed.

To Reproduce

I ran

alembic -c test.ini revision --autogenerate -m "Add column"

in a local Python 3.13 environment.

Error

See above.

Versions.

• OS: macOS 13.7.5 (22H527)
• Python: Python 3.13.2 (main, Feb 8 2025, 23:18:32) [Clang 14.0.3 (clang-1403.0.22.14.1)] on darwin
• Alembic: 1.15.2
• SQLAlchemy: 2.0.39
• Database: PG 14.17
• DBAPI: psycopg-binary 3.2.6

Additional context

I’ve not modified a warnings filter, so I’m a little surprised that the deprecation warning fails Alembic.

[CaselIT]

Thanks for reporting!

[sqla-tester]

Jens Troeger has proposed a fix for this issue in the main branch:

Replace use of utcnow() with now() for Python 3.13 compatibility, Fixes #1643 https://gerrit.sqlalchemy.org/c/sqlalchemy/alembic/+/5892