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gh-136394: Fix race condition in test_zstd #136432

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Merged
merged 2 commits into from
Jul 10, 2025
Merged

gh-136394: Fix race condition in test_zstd #136432

merged 2 commits into from
Jul 10, 2025

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Rogdham
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@Rogdham Rogdham commented Jul 8, 2025

Apply a suggestion of @emmatyping to solve the race condition identified in gh-136394:

one solution would be to call .compress in the main thread before other threads run so that the other threads should generate identical content and thread ordering shouldn't matter.

Needs backport to 3.14 only.

@bedevere-app bedevere-app bot added awaiting review tests Tests in the Lib/test dir labels Jul 8, 2025
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@ZeroIntensity ZeroIntensity requested a review from emmatyping July 8, 2025 18:08
@ZeroIntensity ZeroIntensity added the needs backport to 3.14 bugs and security fixes label Jul 8, 2025
@emmatyping emmatyping mentioned this pull request Jul 9, 2025
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emmatyping
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!buildbot nogil

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🤖 New build scheduled with the buildbot fleet by @ZeroIntensity for commit 81a1bd7 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F136432%2Fmerge

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ZeroIntensity
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Buildbots are happy!

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I also ran the tests 5000 times with this change and found no failures

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Rogdham commented Jul 10, 2025

I also checked in the conditions in which I was able to trigger the issue within a few dozen tries on my machine before the PR, and the issue did not show within 5000 tries with the code from this PR.

So I would say that this fix works as indented, your idea @emmatyping was a good call!

@ZeroIntensity ZeroIntensity merged commit f519918 into python:main Jul 10, 2025
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Thanks @Rogdham for the PR, and @ZeroIntensity for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Jul 10, 2025
@Rogdham @miss-islington
pythongh-136394: Fix race condition in test_zstd (pythonGH-136432)
2402412 
(cherry picked from commit f519918)

Co-authored-by: Rogdham <3994389+Rogdham@users.noreply.github.com>
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bedevere-app bot commented Jul 10, 2025

GH-136506 is a backport of this pull request to the 3.14 branch.

@bedevere-app bedevere-app bot removed the needs backport to 3.14 bugs and security fixes label Jul 10, 2025
ZeroIntensity pushed a commit that referenced this pull request Jul 10, 2025
@miss-islington @Rogdham
[3.14] gh-136394: Fix race condition in test_zstd (GH-136432) (GH-136506
da8bcfd 
)

gh-136394: Fix race condition in test_zstd (GH-136432)
(cherry picked from commit f519918)

Co-authored-by: Rogdham <3994389+Rogdham@users.noreply.github.com>
@Rogdham Rogdham deleted the fix-test_compress_locking-race-condition branch July 10, 2025 14:06
AndPuQing pushed a commit to AndPuQing/cpython that referenced this pull request Jul 11, 2025
@Rogdham @AndPuQing
pythongh-136394: Fix race condition in test_zstd (pythonGH-136432)
b0793d2
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