python / python/cpython

glob.translate incorrectly treats ***

Open
#131,478 7 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

stdlib type-bug
Dominant language
Python
Stars
77.2k
Forks
35.9k
PR merge metrics
PR metrics pending

Description

Bug report

Bug description:

While I could not find relevant manpage or other Unix standard, gitignore states:

Two consecutive asterisks ("**") in patterns matched against full pathname may have special meaning:

A leading "**" followed by a slash means match in all directories. For example, "**/foo" matches file or directory "foo" anywhere, the same as pattern "foo". "**/foo/bar" matches file or directory "bar" anywhere that is directly under directory "foo".

A trailing "/**" matches everything inside. For example, "abc/**" matches all files inside directory "abc", relative to the location of the .gitignore file, with infinite depth.

A slash followed by two consecutive asterisks then a slash matches zero or more directories. For example, "a/**/b" matches "a/b", "a/x/b", "a/x/y/b" and so on.

Other consecutive asterisks are considered regular asterisks and will match according to the previous rules.

My understanding of the last sentence is that a triple asterisk *** (and any longer) should be treated exactly the same as a single one *, but it is not the case. While close, and definitely neither a double asterisk nor a naive repetition of a single one, it has an incorrect quantifier. It is likely caused because the first * is neither surrounded by path separators, nor by string begin/end.

import glob;
print(glob.translate('*', include_hidden=True, recursive=True))
print(glob.translate('***', include_hidden=True, recursive=True))

Expected behavior:

(?s:[^/]+)\Z
(?s:[^/]+)\Z

Actual behavior:

(?s:[^/]+)\Z
(?s:[^/]*)\Z
CPython versions tested on:

3.13

Operating systems tested on:

Linux

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by running the provided glob.translate examples and inspect the glob.translate entry point. Compare the handling of '' and '**' under recursive matching, then add coverage for the expected identical regular expressions and verify the reported behavior on Python 3.13.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
operating-systems
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
48/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.