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Rule.compile uses non-greedy regex to merge slashes #3121
Description
The following 2 lines:
werkzeug/src/werkzeug/routing/rules.py
Line 725 in 64b09e7
werkzeug/src/werkzeug/routing/matcher.py
Line 181 in 64b09e7
Uses a non-greedy quantifier. But {2,} suggests it wants to recognize 2 or more repetitions, but {2,}? will only match 2 repetitions.
A small test script:
import re
def _merge_slashes(url:str, re_str:str):
print(f' using {repr(re_str)}:', re.sub(re_str, "/", url))
def merge_slashes(url:str):
print(f'Merge: {url}')
_merge_slashes(url, "/{2,}?")
_merge_slashes(url, "/{2,}")
merge_slashes('/path/to/foo')
merge_slashes('//path//to//foo')
merge_slashes('///path///to///foo')
merge_slashes('////path////to////foo')with output:
Merge: /path/to/foo
using '/{2,}?': /path/to/foo
using '/{2,}': /path/to/foo
Merge: //path//to//foo
using '/{2,}?': /path/to/foo
using '/{2,}': /path/to/foo
Merge: ///path///to///foo
using '/{2,}?': //path//to//foo
using '/{2,}': /path/to/foo
Merge: ////path////to////foo
using '/{2,}?': //path//to//foo
using '/{2,}': /path/to/foo
Activity
davidism commentedon Mar 6, 2026
Makes sense, happy to review a (human written) PR!
routing: fix non-greedy regex in merge_slashes
themavik commentedon Mar 19, 2026