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Egg race condition #1418

merged 3 commits into from Jul 20, 2018


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pganssle commented Jul 11, 2018

Summary of changes

This PR is an approach to #1412 that adds a test to induce this race condition. The test relies on implementation details, but that is made explicit in the text of the test, I have done it this way because there isn't another great way to deterministically induce the problem.

cc: @JonKohler

Closes #1256

Pull Request Checklist

  • Changes have tests
  • News fragment added in changelog.d. See documentation for details

@pganssle pganssle force-pushed the pganssle:egg_race_condition branch from 16ab345 to 07eb87f Jul 11, 2018

@pganssle pganssle referenced this pull request Jul 11, 2018


Solve race during creation of egg cache (fixes #1256) #1412

2 of 2 tasks complete

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JonKohler commented Jul 11, 2018

Thanks for tackling this, I appreciate it! +1 from me

@pganssle pganssle force-pushed the pganssle:egg_race_condition branch from 07eb87f to e36c32d Jul 11, 2018

pganssle and others added some commits Jul 11, 2018

Add test for cache_path race condition
This mocks out the isdir call so that the directory is created
immediately after you determine whether or not it exists, thus
simulating a race condition between two threads or processes
creating the same directory.
Fix race condition in _bypass_ensure_directory
This fixes a race condition in _bypass_ensure_directory where
two threads or processes may erroneously fail because they are
both creating the same directory. A more robust implementation
of this may involve exposing the un-wrapped os.makedirs.

Originally reported with proposed patch by @JonKohler in
github PR #1412. This patch came out of discussions on that

@pganssle pganssle force-pushed the pganssle:egg_race_condition branch from 601217f to 67f190a Jul 12, 2018


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JonKohler commented Jul 18, 2018

Where are we at on this? is there anything remaining?

Does this replace my original PR?


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pganssle commented Jul 20, 2018

Yes this should replace your original PR since it solves the same problem in a different way. I've seen no objections since I opened this PR so I'm going to merge it.

@pganssle pganssle merged commit e2dde5b into pypa:master Jul 20, 2018

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