Rewrite asyncio.wait_for using asyncio.timeout

[kumaraditya303]

Over the years a lot of issues have accumulated for asyncio.wait_for and the code has become complicated. The asyncio.timeout can be used to simplify this a lot and will also fix bugs which are already fixed or don't exist in asyncio.timeout. This rewrite won't be backported. asyncio.wait_for should be nothing more than a wrapper around asyncio.timeout.

asyncio.wait_for issues: https://github.com/python/cpython/issues?q=is%3Aissue+is%3Aopen+wait_for+label%3Aexpert-asyncio

Linked PRs

• GH-96764: rewrite asyncio.wait_for to use asyncio.timeout #98518

[gvanrossum]

Note that whatever we do should preserve all the existing behavior in wait_for(). Breaking existing code using it would be worse than keeping a bunch of issues that people can avoid by switching to using timeout() directly.

[kumaraditya303]

@graingert IIRC you had a branch for this, interested in this?

[graingert]

Yeah I'm interested, but one thing to note is that wait_for has changed dramatically between versions so matching the behavior is hard

[kumaraditya303]

Yeah I'm interested, but one thing to note is that wait_for has changed dramatically between versions so matching the behavior is hard

It can be evaluated by checking how many tests it breaks by just changing it to use asyncio.timeout and take it from there.

[graingert]

#31847 (comment) here's the work so far

[eIGato]

When can we expect it to be released?
And under what patch number?

[gvanrossum]

3.12

[cretz]

Just want to note on this issue that this change is an unfortunate compatibility break in our Temporal deterministic event loop implementation. We can deterministically implement call_later because it's relative time, but now wait_for uses fixed time of call_at which our time-travelling event loop can't support. I am looking into options...