Autogenerate migration has minor typing issues with mypy

[igorbga]

Using SqlAlchemy 2.X and Alembic 1.11.1.

mypy is complaining about down_revision, branch_labels, and depends_on needing explicit type annotation.

I guess that for down_revision this is only an issue for the first migration because after that it will always be initialized and detected as str.

The fix seems trivial, but I'm not an Alembic expert at all so I might be missing something:

down_revision: Optional[str] = None
branch_labels: Optional[str] = None
depends_on: Optional[str] = None

Maybe this is intended and neccesary in order to keep backwards compatibility with Python 2.x ?

[CaselIT]

Hi,

thanks for reporting.
This can be fixed in the alembic templates, but existing install will need to edit the script.py.mako file

[sqla-tester]

Federico Caselli has proposed a fix for this issue in the main branch:

Added typing to the default script mako templates. https://gerrit.sqlalchemy.org/c/sqlalchemy/alembic/+/4635