mypy 0.920 has incorrect typing for signal handler

[gitpushdashf]

Upgrading from mypy 0.910 to 0.920, I get this:

error: Argument 2 to "signal" has incompatible type "Callable[[int, FrameType], None]"; expected "Union[Callable[[int, Optional[FrameType]], Any], int, Handlers, None]"

https://docs.python.org/3/library/signal.html#signal.signal

[srittau]

This should be reported over at typeshed. That said, the annotations look correct to me. Your function needs to be able to handle a None second argument, according to both the stubs and the documentation.

[gitpushdashf]

Ah, my bad. You are absolutely right. I misread the output, thinking it was expecting a third argument for the handler. I guess this is behaving as expected, so will close it out.

Thank you!

[hauntsaninja]

Thanks for helping find potential issues in new releases!

[gitpushdashf]

No problem at all!

[hauntsaninja]

There's some more discussion here: #5622 (comment)