GeezerVison is showing github.com — gh-95555: Fix a stale comment about negating \P in a character class by fedonman · Pull Request #156490 · python/cpython
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fedonman
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Aug 27, 2026
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edited by bedevere-app
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The comment above the [\P{Alphabetic}] assertion in test_property_escapes still says that, unlike an engine category, \P of a multi-range property cannot be negated inside a character class. GH-152245 lifted that restriction, and the same test now asserts fifty lines below that [\P{ASCII}], [\P{ASCII}abc] and [^\P{ASCII}] all match. The comment now states the distinction that does remain, which is how the member is compiled rather than whether it is allowed:
>>> re._parser.parse(r'[\P{Alphabetic}x]')
[(IN, [(CATEGORY, CATEGORY_NOT_ALPHA), (LITERAL, 120)])]
>>> re._parser.parse(r'[\P{ASCII}x]')
[(BRANCH, (None, [[(LITERAL, 120)], [(IN, [(NEGATE, None), (RANGE, (0, 127))])]]))]test_property_escapes (test.test_re.ReTests.test_property_escapes) ... ok
Total tests: run=1 (filtered)
Result: SUCCESS
Comment-only change in a test file, so there is no news entry.
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…class
pythonGH-152245 lifted the restriction that a negated multi-range property
could not appear inside a character class, and added assertions in
test_property_escapes showing that [\P{ASCII}] and friends now match.
It left in place an earlier comment in the same test saying that,
unlike an engine category, \P of a multi-range property cannot be
negated inside a character class.
The distinction that remains is how the member is compiled, not
whether it is allowed: an engine category joins the set directly as a
CATEGORY, while a multi-range \P is alternated in as a separate branch.
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