[Patches] [Patch #101612] Prevent recursion limit when using ".*?xxx"

[noreply@sourceforge.net]

Patch #101612 has been updated. 

Project: python
Category: Modules
Status: Closed
Submitted by: dgallion
Assigned to : effbot
Summary: Prevent recursion limit when using ".*?xxx"

Follow-Ups:

Date: 2001-Jan-14 15:20
By: effbot

Comment:
I've adapted a variant of this patch.

Not 100% sure this approach works in all cases, but it has survived all
tests I've thrown at it.
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Date: 2000-Sep-22 21:12
By: dgallion

Comment:
This pattern fails with sre:
>>> re.match("(?s){.*?}","{"+' '*17000+"}")
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "E:\pythonWinCVS\python\dist\src\lib\sre.py", line 44, in match
    return _compile(pattern, flags).match(string)
RuntimeError: maximum recursion limit exceeded

The same pattern with even a much larger search buffer works fine on 1.52

This patch optimizes the case ".*?"  and avoids the recursion limit.

After the patch:
>>> import re
>>> re.findall('ab.*?bc', 'abababbc')
['abababbc']
>>> re.findall('ab??bc', 'abababbc')
['abbc']
>>> re.sub("(?s){.*?}","","{"+' '*19047+"}")
''
>>> re.match("(?s){.*?}","{"+' '*16048+"}")
<SRE_Match object at 007E4490>
>>> import test.test_re
Running tests on re.search and re.match
Running tests on re.sub
Running tests on symbolic references
Running tests on re.subn
Running tests on re.split
Running tests on re.findall
Running tests on re.match
Running tests on re.escape
Pickling a RegexObject instance
Test engine limitations
maximum recursion limit exceeded
Running re_tests test suite
>>>



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Date: 2000-Sep-22 21:23
By: tim_one

Comment:
Assigned to Fredrik.

dgallion, please resubmit a context diff.  Straight diffs aren't accepted
(they're too brittle).

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