Fix mypy 1.14.1 error

[notatallshaw]

No description provided.

[notatallshaw]

FYI, this is exactly the literal in typeshed and there is no importable version: https://github.com/python/typeshed/blob/f26ad2059ef33e7aa55a15bf861f594e441de03b/stdlib/tarfile.pyi#L109C11-L109C61

Also pyright is intelligent enough to know that mode isn't an arbitary str but seems mypy isn't 🙁

[sbidoul]

That's quite ugly, if you ask me.

Shall we skip the mypy upgrade until that is solved?

[notatallshaw]

Shall we skip the mypy upgrade until that is solved?

I'll make an MRE, report it to mypy, and see what they say.

[pfmoore]

+1 on getting this fixed in mypy rather than adding that hack - and if we can't get a fix in mypy, I'd prefer using #type: ignore if we want to force things to work.

With luck, it'll just get fixed in mypy, though.

[notatallshaw]

A little digging, this was actually caused by a typeshed change to the signature of tar.open: python/typeshed#12181

mypy consistently upcasts Literal to str when there are multiple different Literal strings in branch statements, I have made a request for them to fix this but it may be that it's working as designed or a long known difficult problem: python/mypy#18442

I'm suspecting it will be easier to go with #type: ignore for now, but I will leave it a day to see if there is any input from mypy.