ignore the ResourceWarnings before they become unraisable exceptions

[graingert]

What do these changes do?

@webknjaz:matrix.org btw you're using PytestUnraisableExceptionWarning incorrectly - you need to ignore the ResourceWarning not the PytestUnraisableExceptionWarning. Because pytest will only collect one unraisable per test and if you allow a ResourceWarning to raise then you defer the cleanup of the underlying resource eg:

_warn("...", ResourceWarning)  # this raises 
self._sock.close()  # this never gets called

Are there changes in behavior for the user?

nope

Related issue number

#6872

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• If you provide code modification, please add yourself to CONTRIBUTORS.txt
  • The format is <Name> <Surname>.
  • Please keep alphabetical order, the file is sorted by names.
• Add a new news fragment into the CHANGES folder
  • name it <issue_id>.<type> for example (588.bugfix)
  • if you don't have an issue_id change it to the pr id after creating the pr
  • ensure type is one of the following:
    • .feature: Signifying a new feature.
    • .bugfix: Signifying a bug fix.
    • .doc: Signifying a documentation improvement.
    • .removal: Signifying a deprecation or removal of public API.
    • .misc: A ticket has been closed, but it is not of interest to users.
  • Make sure to use full sentences with correct case and punctuation, for example: "Fix issue with non-ascii contents in doctest text files."

[codecov]

Codecov Report

Merging #6872 (43c983e) into master (013e45f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 43c983e differs from pull request most recent head d911fa7. Consider uploading reports for the commit d911fa7 to get more accurate results

@@           Coverage Diff           @@
##           master    #6872   +/-   ##
=======================================
  Coverage   93.44%   93.44%           
=======================================
  Files         104      104           
  Lines       30629    30630    +1     
  Branches     3076     3079    +3     
=======================================
+ Hits        28621    28622    +1     
  Misses       1838     1838           
  Partials      170      170           

Flag	Coverage Δ
unit	93.36% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
tests/test_run_app.py	86.64% <100.00%> (ø)
tests/test_tcp_helpers.py	84.61% <100.00%> (+0.30%)	⬆️

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[patchback]

Backport to 3.9: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply 799dc87 on top of patchback/backports/3.9/799dc8742e2cc0b5a819ba454878d09bbfe2df82/pr-6872

Backporting merged PR #6872 into master

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https://github.com/aio-libs/aiohttp.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.9/799dc8742e2cc0b5a819ba454878d09bbfe2df82/pr-6872 upstream/3.9

4. Now, cherry-pick PR ignore the ResourceWarnings before they become unraisable exceptions #6872 contents into that branch:

   $ git cherry-pick -x 799dc8742e2cc0b5a819ba454878d09bbfe2df82

   If it'll yell at you with something like fatal: Commit 799dc8742e2cc0b5a819ba454878d09bbfe2df82 is a merge but no -m option was given., add -m 1 as follows intead:

   $ git cherry-pick -m1 -x 799dc8742e2cc0b5a819ba454878d09bbfe2df82

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR ignore the ResourceWarnings before they become unraisable exceptions #6872 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.9/799dc8742e2cc0b5a819ba454878d09bbfe2df82/pr-6872

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[webknjaz]

@graingert any suggestions on how to make this scoped to a single module?

[graingert]

You'll have to talk to @vstinner on how to get per module resource warnings

You can dig out the original owner of the object via tracemalloc but it slows down python considerably, The issue being tracemalloc is great and gives you all the info you need, but it's too slow to run all the time, also resources warnings are flakey which means by the time you see one it's too late and you weren't running tracemalloc

What I think should happen is that:

• When any object with a custom __del__ is being constructed
• If the ResourceWarning filter is configured as "error"
• the frame module, filename and line number 2 frames above the last __init__ call is recorded, as a sort of tracemalloc of last-resort

Then when the ResourceWarning is raised it's associated with those lines

[webknjaz]

Backported as e4266b1 + 8201922.

[webknjaz]

Also backported to 3.8 as 4d10cc9

[patchback]

Backport to 3.8: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply 799dc87 on top of patchback/backports/3.8/799dc8742e2cc0b5a819ba454878d09bbfe2df82/pr-6872

Backporting merged PR #6872 into master

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https://github.com/aio-libs/aiohttp.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.8/799dc8742e2cc0b5a819ba454878d09bbfe2df82/pr-6872 upstream/3.8

4. Now, cherry-pick PR ignore the ResourceWarnings before they become unraisable exceptions #6872 contents into that branch:

   $ git cherry-pick -x 799dc8742e2cc0b5a819ba454878d09bbfe2df82

   If it'll yell at you with something like fatal: Commit 799dc8742e2cc0b5a819ba454878d09bbfe2df82 is a merge but no -m option was given., add -m 1 as follows intead:

   $ git cherry-pick -m1 -x 799dc8742e2cc0b5a819ba454878d09bbfe2df82

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR ignore the ResourceWarnings before they become unraisable exceptions #6872 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.8/799dc8742e2cc0b5a819ba454878d09bbfe2df82/pr-6872

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.