argparse.ArgumentParser.add_argument doesn't allow type=os.path.abspath

[andymwood]

Running mypy on this code:

import argparse,  os
reveal_type(os.path.abspath)
p = argparse.ArgumentParser()
p.add_argument("file", type=os.path.abspath)

I get:

mypy args.py 
args.py:2: note: Revealed type is 'Overload(def [AnyStr in (builtins.str, builtins.bytes)] (path: builtins._PathLike[AnyStr`-1]) -> AnyStr`-1, def [AnyStr in (builtins.str, builtins.bytes)] (path: AnyStr`-1) -> AnyStr`-1)'
args.py:4: error: Argument "type" to "add_argument" of "_ActionsContainer" has incompatible type overloaded function; expected "Union[Callable[[str], AnyStr], FileType]"

I originally thought this might be an issue with typeshed and reported it here, but it turns out that pytype accepts the code.

[ilevkivskyi]

It seems to me the mypy problem here is a duplicate of #1317.

But there is also a typeshed issue IMO (fixing which will fix this issue), so you might want to open an issue there. The add_argument method is needlessly generic, replacing _T with Any there will not reduce the strictness of the method.

cc @JelleZijlstra

[andymwood]

But there is also a typeshed issue IMO (fixing which will fix this issue), so you might want to open an issue there.

I originally reported the issue here but was told it was probably a mypy issue. I'll re-open that issue and let you guys fight it out amongst yourselves.