[issue1647489] zero-length match confuses re.finditer()

Change by Serhiy Storchaka : -- resolution: -> fixed stage: patch review -> resolved status: open -> closed ___ Python tracker ___ ___

[issue1647489] zero-length match confuses re.finditer()

Serhiy Storchaka added the comment: New changeset 70d56fb52582d9d3f7c00860d6e90570c6259371 by Serhiy Storchaka in branch 'master': bpo-25054, bpo-1647489: Added support of splitting on zerowidth patterns. (#4471) https://github.com/python/cpython/commit/70d56fb52582d9d3f7c00860d6e90570c625937

[issue1647489] zero-length match confuses re.finditer()

Change by Serhiy Storchaka : -- pull_requests: +4587 ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: https:/

[issue1647489] zero-length match confuses re.finditer()

Change by Serhiy Storchaka : -- keywords: +patch pull_requests: +4404 stage: -> patch review ___ Python tracker ___ ___ Python-bug

[issue1647489] zero-length match confuses re.finditer()

Change by Serhiy Storchaka : -- components: +Library (Lib) nosy: +ezio.melotti type: -> behavior ___ Python tracker ___ ___ Python

[issue1647489] zero-length match confuses re.finditer()

Change by Serhiy Storchaka : -- assignee: niemeyer -> serhiy.storchaka nosy: +serhiy.storchaka versions: +Python 3.6, Python 3.7 ___ Python tracker ___ ___

[issue1647489] zero-length match confuses re.finditer()

Changes by Mark Lawrence : -- nosy: -BreamoreBoy ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: https://mai

[issue1647489] zero-length match confuses re.finditer()

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[issue1647489] zero-length match confuses re.finditer()

Mark Lawrence added the comment: How does "the Regexp 2.7 engine in issue 2636" from msg73742 deal with this situation? -- nosy: +BreamoreBoy ___ Python tracker ___ __

[issue1647489] zero-length match confuses re.finditer()

Martin Morrison added the comment: This is still an issue today: >>> import re >>> [m.groups() for m in re.finditer(r'(^z*)|(\w+)', 'abc')] [('', None), (None, 'bc')] -- nosy: +isoschiz ___ Python tracker __

[issue1647489] zero-length match confuses re.finditer()

Denver Coneybeare added the comment: I just re-tested this issue in trunk at changeset 053bc5ca199b and the issue is still exactly reproducible as originally reported. That is, the match to the empty string skips a character of the match: >>> import re >>> [m.groups() for m in re.finditer(r'

[issue1647489] zero-length match confuses re.finditer()

Jeffrey C. Jacobs <[EMAIL PROTECTED]> added the comment: Matthew, I'll try to merge all your diffs with the current repository over the weekend. Having done the first, I know where code differs between your implementation, mine and the base, so I can apply your patch, and then a patch that resto

[issue1647489] zero-length match confuses re.finditer()

Matthew Barnett <[EMAIL PROTECTED]> added the comment: I have to report that the fix appears to be successful: >>> print [m.groups() for m in re.finditer(r'(^z*)|(\w+)', 'abc')] [('', None), (None, 'abc')] >>> print re.findall(r"(^z*)|(\w+)", "abc") [('', ''), ('', 'abc')] >>> print [m.groups()

[issue1647489] zero-length match confuses re.finditer()

Jeffrey C. Jacobs <[EMAIL PROTECTED]> added the comment: Perl gives this result for your new expression: "",undef,undef undef,undef,"abc" undef,"",undef I think it has to do with not thinking of a string as a sequence of characters, but as a sequence of characters separated by null-space. Null

[issue1647489] zero-length match confuses re.finditer()

Matthew Barnett <[EMAIL PROTECTED]> added the comment: FYI, I posted msg73737 after finding that the fix for the original case was really very simple, but then thought about whether it would behave as expected when there were more zero-width matches, hence the later posts. __

[issue1647489] zero-length match confuses re.finditer()

Matthew Barnett <[EMAIL PROTECTED]> added the comment: What about r'(^z*)|(q*)|(\w+)'? I could imagine that the first group could match only at the start of the string, but if the second group doesn't have that restriction then it could match the second time, and only after that could the third m

[issue1647489] zero-length match confuses re.finditer()

Jeffrey C. Jacobs <[EMAIL PROTECTED]> added the comment: Ah, I see the problem, if ptr is not incremented, then it will keep matching the first expression, (^z*), so it would have to both 'skip' the 'a' and NOT skip the 'a'. Hmm. You're right, Matthew, this is pretty complicated. Now, for your

[issue1647489] zero-length match confuses re.finditer()

Jeffrey C. Jacobs <[EMAIL PROTECTED]> added the comment: Never mind inclusion in 2.6 as no-one has repeated this bug in re-world examples yet so it's going to have to wait for the Regexp 2.7 engine in issue 2636. -- versions: +Python 2.7 -Python 2.5 _

[issue1647489] zero-length match confuses re.finditer()

Jeffrey C. Jacobs <[EMAIL PROTECTED]> added the comment: Hmmm. This strikes me as a bug, beyond the realm of Issue 3262. The two items may be related, but the dropping of the 'a' seems like unexpected behaviour that I doubt any current code is expecting to occur. Clearly, what is going on is t

[issue1647489] zero-length match confuses re.finditer()

Matthew Barnett <[EMAIL PROTECTED]> added the comment: What should: [m.groups() for m in re.finditer(r'(^z*)|(^q*)|(\w+)', 'abc')] return? Should the second group also yield a zero-width match before the third group is tried? I think it probably should. Does Perl? _

[issue1647489] zero-length match confuses re.finditer()

Changes by Jeffrey C. Jacobs <[EMAIL PROTECTED]>: -- nosy: +timehorse ___ Python tracker <[EMAIL PROTECTED]> ___ ___ Python-bugs-list

[issue1647489] zero-length match confuses re.finditer()

Matthew Barnett <[EMAIL PROTECTED]> added the comment: This also affects re.findall(). -- nosy: +mrabarnett ___ Python tracker <[EMAIL PROTECTED]> ___ __

[issue1647489] zero-length match confuses re.finditer()

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