diff options
Diffstat (limited to 'Lib/fnmatch.py')
| -rw-r--r-- | Lib/fnmatch.py | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/Lib/fnmatch.py b/Lib/fnmatch.py index d7d915d..0eb1802 100644 --- a/Lib/fnmatch.py +++ b/Lib/fnmatch.py @@ -16,6 +16,12 @@ import functools __all__ = ["filter", "fnmatch", "fnmatchcase", "translate"] +# Build a thread-safe incrementing counter to help create unique regexp group +# names across calls. +from itertools import count +_nextgroupnum = count().__next__ +del count + def fnmatch(name, pat): """Test whether FILENAME matches PATTERN. @@ -148,9 +154,12 @@ def translate(pat): # in a lookahead assertion, save the matched part in a group, then # consume that group via a backreference. If the overall match fails, # the lookahead assertion won't try alternatives. So the translation is: - # (?=(P<name>.*?fixed))(?P=name) - # Group names are created as needed: g1, g2, g3, ... - groupnum = 0 + # (?=(?P<name>.*?fixed))(?P=name) + # Group names are created as needed: g0, g1, g2, ... + # The numbers are obtained from _nextgroupnum() to ensure they're unique + # across calls and across threads. This is because people rely on the + # undocumented ability to join multiple translate() results together via + # "|" to build large regexps matching "one of many" shell patterns. while i < n: assert inp[i] is STAR i += 1 @@ -167,7 +176,7 @@ def translate(pat): add(".*") add(fixed) else: - groupnum += 1 + groupnum = _nextgroupnum() add(f"(?=(?P<g{groupnum}>.*?{fixed}))(?P=g{groupnum})") assert i == n res = "".join(res) |