Typing problem: use of @with_argparser will cause mypy to issue an error about cmd2

[anselor]

Thanks for this.

I'll have to set aside some time to play around with it more but I think it's possible if we add a TypeVar declaration like this:

CommandParent = TypeVar('CommandParent', bound=Union[Cmd, CommandSet])

And replace every reference to Cmd or CommandSet in the Callable declarations that would allow subclasses to correctly pass validation.

The declarations would probably need to be changed to something like the following. It would actually simplify it a little bit.

RawCommandFuncOptionalBoolReturn = Callable[[CommandParent, Union[Statement, str]], Optional[bool]]

#: Function signature for a Command Function that uses an argparse.ArgumentParser to process user input
#: and optionally returns a boolean
ArgparseCommandFuncOptionalBoolReturn = Callable[[CommandParent, argparse.Namespace], Optional[bool]]

#: Function signature for a Command Function that uses an argparse.ArgumentParser to process user input
#: and returns a boolean
ArgparseCommandFuncBoolReturn = Callable[[CommandParent, argparse.Namespace], bool]

#: Function signature for an Command Function that uses an argparse.ArgumentParser to process user input
#: and returns nothing
ArgparseCommandFuncNoneReturn = Callable[[CommandParent, argparse.Namespace], None]

#: Aggregate of all accepted function signatures for an argparse Command Function
ArgparseCommandFunc = Union[
    ArgparseCommandFuncOptionalBoolReturn,
    ArgparseCommandFuncBoolReturn,
    ArgparseCommandFuncNoneReturn,
]

[anselor]

@MilanStaffehl
Looks like the changes to type definitions does the trick. I'd appreciate it if you could pull my branch and try it out to verify it also works for you.

There have been a number of fixes recently and I think we should be doing a new release soon.

[MilanStaffehl]

I can confirm that with the changes on the branch the problem no longer occurs for me; mypy passes without an error now. Thanks!

Looking forward to the new release, that's another type: ignore I can remove!

[tleonhardt]

I'm closing this since #1276 appears to have addressed it. If I'm wrong, please feel free to re-open.