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gh-106052: Fix bug in the matching of possessive quantifiers (gh-106515)

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It did not work in the case of a subpattern containing backtracking.

Temporary implement possessive quantifiers as equivalent greedy qualifiers
in atomic groups.
This commit is contained in:
Serhiy Storchaka 2023-08-09 08:47:57 +03:00 • committed by GitHub
parent 73507382ac
commit 7b6e34e5ba
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7
Lib/re/_compiler.py
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@ -100,6 +100,13 @@ def _compile(code, pattern, flags):
emit(ANY_ALL)
else:
emit(ANY)
elif op is POSSESSIVE_REPEAT:
# gh-106052: Possessive quantifiers do not work when the
# subpattern contains backtracking, i.e. "(?:ab?c)*+".
# Implement it as equivalent greedy qualifier in atomic group.
p = [(MAX_REPEAT, av)]
p = [(ATOMIC_GROUP, p)]
_compile(code, p, flags)
elif op in REPEATING_CODES:
if _simple(av[2]):
emit(REPEATING_CODES[op][2])