René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Speed up `pathlib.Path.glob()` by removing redundant regex matching","articleBody":"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.\r\n\r\nHowever! 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](https://github.com/python/cpython/pull/104512#discussion_r1212825322) at the time.\r\n\r\nWe should be able to improve performance by building an `re.Pattern` only for segments following `**` wildcards, and not the entire `glob()` pattern.\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-115061\n* gh-116152\n* gh-117732\n* gh-117831\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/barneygale","@type":"Person","name":"barneygale"},"datePublished":"2024-02-06T03:53:20.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/115060/cpython/issues/115060"}