[3.13] gh-125245: Fix race condition when importing collections.abc (GH-125415)
          #125944
        
          
      
  Add this suggestion to a batch that can be applied as a single commit.
  This suggestion is invalid because no changes were made to the code.
  Suggestions cannot be applied while the pull request is closed.
  Suggestions cannot be applied while viewing a subset of changes.
  Only one suggestion per line can be applied in a batch.
  Add this suggestion to a batch that can be applied as a single commit.
  Applying suggestions on deleted lines is not supported.
  You must change the existing code in this line in order to create a valid suggestion.
  Outdated suggestions cannot be applied.
  This suggestion has been applied or marked resolved.
  Suggestions cannot be applied from pending reviews.
  Suggestions cannot be applied on multi-line comments.
  Suggestions cannot be applied while the pull request is queued to merge.
  Suggestion cannot be applied right now. Please check back later.
  
    
  
    
If multiple threads concurrently imported
collections.abc, some of thethreads might incorrectly see the "shim"
Lib/collections/abc.pymoduleinstead of the correct
Lib/_collections_abc.pymodule. This affectedboth the free threading build and the default GIL-enabled build.
(cherry picked from commit fed501d)
Co-authored-by: Sam Gross [email protected]
collections.abc#125245