In #104512 we made pathlib.Path.glob() use a "walk-and-filter" strategy for expanding ** wildcards in patterns: when we encounter a ** segment, we immediately consume subsequent segments and use them to build a regex that is used to filter results. This saves a bunch of scandir() calls.

However! We actually build a regex for the entire pattern given to glob(), rather than just the segments following ** wildcards. And so when evaluating a pattern like dir*/**/file*, the dir* part is needlessly matched twice against each path. @zooba noted this in a review comment at the time.

We should be able to improve performance by building an re.Pattern only for segments following ** wildcards, and not the entire glob() pattern.

Linked PRs

• GH-115060: Speed up pathlib.Path.glob() by removing redundant regex matching #115061
• GH-115060: Speed up pathlib.Path.glob() by skipping directory scanning #116152
• GH-115060: Speed up pathlib.Path.glob() by not scanning literal parts #117732
• GH-115060: Speed up pathlib.Path.glob() by omitting initial stat() #117831