`asyncio.Timeout.__aexit__` does not handle `BaseExceptionGroup`

Bug report

Bug description:

There may be a good reason for this I am not seeing, but in the asyncio.Timeout.__aexit__ handler, the exception group handling seems too narrow:

https://github.com/python/cpython/blob/9743d069bd53e9d3a8f09df899ec1c906a79da24/Lib/asyncio/timeouts.py#L113-L119

Given exc_val itself can be a BaseException and _insert_timeout_error takes a BaseException as an argument, I fail to see a reason not to check for superclass BaseExceptionGroup instead.

https://github.com/python/cpython/blob/9743d069bd53e9d3a8f09df899ec1c906a79da24/Lib/asyncio/timeouts.py#L133

This no longer impacts me as I implemented what I was aiming for in a better way, but it still looks like a bug. Is it?

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Linked PRs

• gh-137797