gh-133893: asyncio.graph: Replace TextIO annotation with io.Writer

[srittau]

Considering that this is a new module in 3.14, I think this should be backported.

• Issue: asyncio.graph.format_call_graph() should use io.Writer instead of typing.TextIO #133893

[sobolevn]

I don't think that news entry should be added here, there's no user-visible change.

Other than that - LGTM! 👍

[sobolevn]

Thank you!

[miss-islington-app]

Thanks @srittau for the PR, and @sobolevn for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

[bedevere-app]

GH-133901 is a backport of this pull request to the 3.14 branch.

[sobolevn]

@srittau @JelleZijlstra do know how we can type-check this file and several others in Lib/asyncio/? It might be a good idea. Depending on how complex the setup will be.

[srittau]

Type checking in the standard library has been a contentious issue, see for example https://discuss.python.org/t/type-annotations-in-the-stdlib/21487/2

I personally think that all annotated code in the standard library should be type checked, but this is probably a PEP-level problem that will cause a lot of pushback.

[JelleZijlstra]

There's also practical issues because type checkers assume standard library code is in typeshed. @ambv talked on the core.py podcast recently about how they achieved type checking for pyrepl with some symlink trick; but pyrepl might be a slightly easier case because it's private and not in typeshed.

[sobolevn]

I already sneaked into tomllib type-checking, see: #133118

It might be a reference for future work.