v1.10.4 -> v1.11.0: pyright: "__setitem__" method not defined on type "Mapping[str, str]"

[gitpushdashf]

Hi Alembic and all,

There seems to be a type change (for better or for worse) that's being caught by pyright -- possibly others.

We have a migration env.py with a statement like configuration["sqlalchemy.url"] = database that's throwing the error when pyright runs. With v1.10.4, there's no such error. I'm not sure if this is part of autogenerated output, if the code was a bit invalid from the start, or if there's something else going on.

In this case, configuration = config.get_section(config.config_ini_section), config = context.config, and from alembic import context.

Let me know if I can provide anything else to help debug.

Thanks!

[zzzeek]

I would assume you are asserting that the return is not None since the previous type had it as Optional[Dict[str, str]]

[gitpushdashf]

Oh, interesting. I wonder if Dict has __setitem__ but Mapping does not? Would Dict be a better type?

[sqla-tester]

Mike Bayer has proposed a fix for this issue in the main branch:

restore Dict[str, str] as potential get_section() type https://gerrit.sqlalchemy.org/c/sqlalchemy/alembic/+/4619

[zzzeek]

it's supposed to be Dict for this case.