errors for flask.Blueprint definitions with pyright 1.1.395

[matt-the-midnight-hacker]

Hi I just updated pyright and I now get in my flask view modules errors reported.
My code looks like blueprint = flask.Blueprint("my_view", __name__)
and pyright finds: error: Argument of type "object" cannot be assigned to parameter "cli_group" of type "str | None" in function "__init__"

Note that I do not assign "cli_group". Actually just the default value should get used.
It might be correct that there is something wrong with the assignment in the flask blueprint module but since it is not on my
code there is not much I can do about that other then assigning a value. But since I just want the default behavior I'd prefer not to set it everywhere.

Should pyright really report an error on my module if the actual issue happens in flask/blueprints.py?

The flask code in question looks like this btw.

from .sansio.scaffold import _sentinel

class Blueprint(SansioBlueprint):
    def __init__(
        self,
        name: str,
        import_name: str,
        (omit ..)
        cli_group: str | None = _sentinel,  # type: ignore
    ) -> None:

[erictraut]

Your question is a reasonable one. I've started a discussion in the Python typing forum to get feedback from the broader typing community. Feel free to join in on that discussion if you have an opinion.

Regardless of how the discussion pans out, the above snippet is clearly a bug in the library code. I recommend that you report it to the library maintainer. Adding a # type: ignore to the code simply masks the bug. It should be fixed properly by correcting the annotation for the cli_group parameter.

[matt-the-midnight-hacker]

Thank you for taking this topic to the python typing forum. I just read the discussion. I think there isn't much more I can add to it though. As I already expressed in my previous message. I also would prefer not like not to get errors reported for library code I can not control.

[matt-the-midnight-hacker]

I just noticed this issue was already fixed/reverted by you. Appreciate the fast reaction. Thank you.