Fix unused snapshots not triggering failure in CI

[epenet]

Proposed change

syrupy is currently unable to detect unused snapshots when it is run in conjuction with xdist
It is a know existing limitation of syrupy https://github.com/syrupy-project/syrupy?tab=readme-ov-file#known-limitations

See also:
syrupy-project/syrupy#535

I have started work on implementing a clean version upstream: syrupy-project/syrupy#901, but I recommend that we add this workaround temporarily, until it is finalised there.

Sample failed run:
https://github.com/home-assistant/core/actions/runs/11380993290/job/31661830329

Type of change

• Dependency upgrade
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• Breaking change (fix/feature causing existing functionality to break)
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Additional information

• This PR fixes or closes issue: fixes #
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[mib1185]

unfortunately, I think reverting #127736 is the more reasonable option in this case, since not detecting unused snapshots while running with pytest-xdist is a known limitation of syrupy (syrupy-project/syrupy#668)

[epenet]

Aaargghh. This works for me locally - but still fails to catch them inside CI

[frenck]

This sounds like a workaround for an upstream issue?

I honestly really don't think this belongs in our codebase.

[epenet]

This sounds like a workaround for an upstream issue?

Yes it is a workaround for an upstream issue.
There is a PR open there, but it fills a gap right now, see #128477

I honestly really don't think this belongs in our codebase.

I have added a comment to indicate that it can be removed when upstream is implemented

[home-assistant]

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[epenet]

@frenck, this now passes CI (as #128549 has been merged)

Would you consider adding this as a temporary workaround until the upstream issue is resolved?

[frenck]

@frenck, this now passes CI (as #128549 has been merged)

Would you consider adding this as a temporary workaround until the upstream issue is resolved?

Makes sense 👍

[frenck]

Thanks, @epenet 👍

../Frenck

[jbouwh]

This fix seems to cause a performance regression as a side effect.

E.g.:
pytest -n auto tests/components/mqtt/

This takes 25.75 sec without this fix on my dev env. and 72.24 sec with.

When coverage is tested too, it gets worse:
This takes 46.24 sec without this fix and 189.09 sec with.

[frenck]

Than we need to revert 👍

[epenet]

Happy to revert - but I had checked overall run time and didn't see such discrepancy.