No time zone data on Windows, error setting timezone in alembic.ini

[floxay]

Describe the bug
Setting timezone to --for example-- UTC on Windows will fail with the error Can't locate timezone: UTC as Windows does not have time zone data.
Related docs: https://docs.python.org/3/library/zoneinfo.html#data-sources

Expected behavior
Setting timezone in alembic.ini should work on Windows "out of the box". Or alembic should at least provide a better error message in this case.

To Reproduce
On Windows use this config and attempt to create a new migration.

timezone = UTC

Error

Traceback (most recent call last):
  File "C:\Program Files\Python312\Lib\runpy.py", line 198, in _run_module_as_main
    return _run_code(code, main_globals, None,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\runpy.py", line 88, in _run_code
    exec(code, run_globals)
  File "c:\Users\floxay\.vscode\extensions\ms-python.debugpy-2024.11.2024082901-win32-x64\bundled\libs\debugpy\adapter/../..\debugpy\launcher/../..\debugpy\__main__.py", line 71, in <module>
    cli.main()
  File "c:\Users\floxay\.vscode\extensions\ms-python.debugpy-2024.11.2024082901-win32-x64\bundled\libs\debugpy\adapter/../..\debugpy\launcher/../..\debugpy/..\debugpy\server\cli.py", line 486, in main
    run()
  File "c:\Users\floxay\.vscode\extensions\ms-python.debugpy-2024.11.2024082901-win32-x64\bundled\libs\debugpy\adapter/../..\debugpy\launcher/../..\debugpy/..\debugpy\server\cli.py", line 369, in run_module
    run_module_as_main(options.target, alter_argv=True)
  File "c:\Users\floxay\.vscode\extensions\ms-python.debugpy-2024.11.2024082901-win32-x64\bundled\libs\debugpy\_vendored\pydevd\_pydevd_bundle\pydevd_runpy.py", line 238, in _run_module_as_main
    return _run_code(code, main_globals, None,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\.vscode\extensions\ms-python.debugpy-2024.11.2024082901-win32-x64\bundled\libs\debugpy\_vendored\pydevd\_pydevd_bundle\pydevd_runpy.py", line 124, in _run_code
    exec(code, run_globals)
  File "c:\Users\floxay\x\.venv\Lib\site-packages\litestar\__main__.py", line 10, in <module>
    run_cli()
  File "c:\Users\floxay\x\.venv\Lib\site-packages\litestar\__main__.py", line 6, in run_cli
    litestar_group()
  File "c:\Users\floxay\x\.venv\Lib\site-packages\rich_click\rich_command.py", line 367, in __call__
    return super().__call__(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\click\core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\rich_click\rich_command.py", line 152, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\click\core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\click\core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\click\core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\click\core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\click\decorators.py", line 33, in new_func
    return f(get_current_context(), *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\litestar\cli\_utils.py", line 254, in wrapped
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\click\decorators.py", line 33, in new_func
    return f(get_current_context(), *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\litestar\cli\_utils.py", line 254, in wrapped
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\advanced_alchemy\extensions\litestar\cli.py", line 226, in create_revision
    alembic_commands.revision(
  File "c:\Users\floxay\x\.venv\Lib\site-packages\advanced_alchemy\alembic\commands.py", line 176, in revision
    return migration_command.revision(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\alembic\command.py", line 243, in revision
    scripts = [script for script in revision_context.generate_scripts()]
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\alembic\autogenerate\api.py", line 650, in generate_scripts
    yield self._to_script(generated_revision)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\alembic\autogenerate\api.py", line 555, in _to_script
    return self.script_directory.generate_revision(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\alembic\script\base.py", line 689, in generate_revision
    create_date = self._generate_create_date()
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\floxay\x\.venv\Lib\site-packages\alembic\script\base.py", line 624, in _generate_create_date
    raise util.CommandError(
alembic.util.exc.CommandError: Can't locate timezone: UTC

Versions.

• OS: Windows
• Python: 3.12.5
• Alembic: 1.13.2
• SQLAlchemy: 2.0.32
• Database: PG16
• DBAPI: postgresql+asyncpg

Additional context
Adding tzdata as a dependency on Windows as recommended in the zoneinfo documentation solves the issue.

[CaselIT]

Hi,

I can't reproduce. I don't know what python version you have, but trying in an empty env works without issues:

$ pip list
Package    Version
---------- -------
pip        24.2
setuptools 72.1.0
wheel      0.43.0

$ python
Python 3.12.4 | packaged by Anaconda, Inc. | (main, Jun 18 2024, 15:03:56) [MSC v.1929 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import zoneinfo
>>> zoneinfo.ZoneInfo('UTC')
zoneinfo.ZoneInfo(key='UTC')
>>>

[floxay]

I suspect it works for you due to Anaconda providing time zone data in some way? Just guessing.

I get the following in a fresh venv created by uv:

Python 3.12.5 (tags/v3.12.5:ff3bc82, Aug  6 2024, 20:45:27) [MSC v.1940 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import zoneinfo
>>> zoneinfo.ZoneInfo('UTC')
Traceback (most recent call last):
  File "C:\Program Files\Python312\Lib\zoneinfo\_common.py", line 12, in load_tzdata
    return resources.files(package_name).joinpath(resource_name).open("rb")
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\importlib\resources\_common.py", line 46, in wrapper
    return func(anchor)
           ^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\importlib\resources\_common.py", line 56, in files
    return from_package(resolve(anchor))
                        ^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\functools.py", line 907, in wrapper
    return dispatch(args[0].__class__)(*args, **kw)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\importlib\resources\_common.py", line 82, in _
    return importlib.import_module(cand)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\importlib\__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1310, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1324, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'tzdata'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Program Files\Python312\Lib\zoneinfo\_common.py", line 24, in load_tzdata
    raise ZoneInfoNotFoundError(f"No time zone found with key {key}")
zoneinfo._common.ZoneInfoNotFoundError: 'No time zone found with key UTC'
>>>

[CaselIT]

it seems to be the case.

Since the alembic.ini mentions how timezone works. It could mention that tzdata may need to be installed, but otherwise I don't think it should be installed by defult

[CaselIT]

if you can send a PR to improve them it would be appreciated. The templates are here https://github.com/sqlalchemy/alembic/tree/main/alembic/templates

[floxay]

Opened #1529 for it

[zzzeek]

superseded by #1556