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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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3 changed files with 21 additions and 0 deletions
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12
Lib/test/test_re.py
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@ -2342,6 +2342,16 @@ class ReTests(unittest.TestCase):
self.assertTrue(re.fullmatch(r'(?s:(?>.*?\.).*)\Z', "a.txt")) # reproducer
self.assertTrue(re.fullmatch(r'(?s:(?=(?P<g0>.*?\.))(?P=g0).*)\Z', "a.txt"))
def test_bug_gh106052(self):
self.assertEqual(re.match("(?>(?:ab?c)+)", "aca").span(), (0, 2))
self.assertEqual(re.match("(?:ab?c)++", "aca").span(), (0, 2))
self.assertEqual(re.match("(?>(?:ab?c)*)", "aca").span(), (0, 2))
self.assertEqual(re.match("(?:ab?c)*+", "aca").span(), (0, 2))
self.assertEqual(re.match("(?>(?:ab?c)?)", "a").span(), (0, 0))
self.assertEqual(re.match("(?:ab?c)?+", "a").span(), (0, 0))
self.assertEqual(re.match("(?>(?:ab?c){1,3})", "aca").span(), (0, 2))
self.assertEqual(re.match("(?:ab?c){1,3}+", "aca").span(), (0, 2))
@unittest.skipIf(multiprocessing is None, 'test requires multiprocessing')
def test_regression_gh94675(self):
pattern = re.compile(r'(?<=[({}])(((//[^\n]*)?[\n])([\000-\040])*)*'
@ -2441,6 +2451,7 @@ ATOMIC_GROUP
17: SUCCESS
''')
@unittest.expectedFailure # gh-106052
def test_possesive_repeat_one(self):
self.assertEqual(get_debug_out(r'a?+'), '''\
POSSESSIVE_REPEAT 0 1
@ -2453,6 +2464,7 @@ POSSESSIVE_REPEAT 0 1
12: SUCCESS
''')
@unittest.expectedFailure # gh-106052
def test_possesive_repeat(self):
self.assertEqual(get_debug_out(r'(?:ab)?+'), '''\
POSSESSIVE_REPEAT 0 1