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Error compiling valid regex #50406
Description
| BPO | 6156 |
|---|---|
| Nosy | @birkenfeld, @ezio-melotti, @serhiy-storchaka |
| Superseder | |
| Files |
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = None
closed_at = <Date 2010-07-29.17:47:04.141>
created_at = <Date 2009-05-31.16:26:01.022>
labels = ['type-bug', 'library']
title = 'Error compiling valid regex'
updated_at = <Date 2017-11-19.19:44:16.097>
user = 'https://bugs.python.org/Eloff'bugs.python.org fields:
activity = <Date 2017-11-19.19:44:16.097>
actor = 'serhiy.storchaka'
assignee = 'none'
closed = True
closed_date = <Date 2010-07-29.17:47:04.141>
closer = 'georg.brandl'
components = ['Library (Lib)']
creation = <Date 2009-05-31.16:26:01.022>
creator = 'Eloff'
dependencies = []
files = ['14141', '14142']
hgrepos = []
issue_num = 6156
keywords = ['patch']
message_count = 8.0
messages = ['88600', '88605', '88646', '88649', '88662', '88667', '111980', '306512']
nosy_count = 6.0
nosy_names = ['georg.brandl', 'Eloff', 'ezio.melotti', 'mrabarnett', 'crchemist', 'serhiy.storchaka']
pr_nums = []
priority = 'normal'
resolution = 'out of date'
stage = None
status = 'closed'
superseder = '2636'
type = 'behavior'
url = 'https://bugs.python.org/issue6156'
versions = ['Python 2.6', 'Python 3.0']
Activity
eloff commentedon May 31, 2009
This works:
r'([xy])(?:\1)+'
This won't compile, "error: nothing to repeat"
r'([xy])(?:\s*\1)+'
I can execute this under other regex engines, and it seems to me that it
really should work.
mrabarnett commentedon May 31, 2009
I agree that it's a bug.
A workaround is r'([xy])(?:\s{0,65534}\1)+'. A repeat of 65535 is
treated as unlimited (but no warning is given).
crchemist commentedon Jun 1, 2009
tests for this issue.
crchemist commentedon Jun 1, 2009
patch that fix this
birkenfeld commentedon Jun 1, 2009
Just taking out the "raise" seems questionable to me; are you sure there
are no valid errors that can be caught there?
crchemist commentedon Jun 1, 2009
birkenfeld commentedon Jul 29, 2010
Closing in favor of bpo-2636, which allows this regex to be compiled.
serhiy-storchaka commentedon Nov 19, 2017
This issue was fixed in bpo-9179.
The issue with 65535 repeats was fixed in bpo-13169.