Avoid errors in cleanup when event loop is already closed

[minrk]

check is_closed() before calling cleanup methods and catch errors in cleanup to avoid problems

closes #1040

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 50.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 90.84%. Comparing base (92b006f) to head (1099d3f).

Files with missing lines	Patch %	Lines
pytest_asyncio/plugin.py	50.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1051      +/-   ##
==========================================
- Coverage   91.31%   90.84%   -0.48%     
==========================================
  Files           2        2              
  Lines         576      579       +3     
  Branches       76       77       +1     
==========================================
  Hits          526      526              
- Misses         30       32       +2     
- Partials       20       21       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[minrk]

Not sure why codecov misreports coverage. A local run shows the missed lines are actually covered by 8bc0e19

[seifertm]

Thanks a lot for the bug fix!

I agree that downgrading exceptions during cleanup to a warning makes sense, as outlined in my comment on the bug report.

I took the liberty to modify the changelog commit history for easier cherry-picking into the v0.25 release branch. I think we should do a separate bugfix release for v0.25, rather than adding this to the v0.26 release.

[minrk]

Thanks!