[ python-Bugs-1058786 ] r'\10' as replacement pattern loops in compilation

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Bugs item #1058786, was opened at 2004-11-02 12:39
Message generated for change (Comment added) made by nmm1
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Category: Regular Expressions
Group: Python 2.2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Nick Maclaren (nmm1)
Assigned to: Gustavo Niemeyer (niemeyer)
Summary: r'\10' as replacement pattern loops in compilation

Initial Comment:
The following program loops under at least Solaris 9
on SPARC and Linux (kernel 2.6) in x86.  From
tracebacks, it seems to be in the internal compilation
of the pattern r'\10'.

from re import compile

line = ""

pat = compile(12 * r'(\d+)')

ltarget = float(pat.sub(r'\10',line))

print ltarget


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>Comment By: Nick Maclaren (nmm1)
Date: 2004-11-02 13:28

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I have also checked, and it is fixed.  From my point of
view, it isn't worth backporting, as I can upgrade and don't
mind using a beta version.


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Comment By: Michael Hudson (mwh)
Date: 2004-11-02 13:07

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It does seem to be fixed in 2.4, but not in 2.3(.3, anyway).

I know some of the re changes for 2.4 are fairly large, so I
don't know whether the fix is a backport candidate for
2.3.5.  Gustavo might know.

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Comment By: Johannes Gijsbers (jlgijsbers)
Date: 2004-11-02 13:07

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I get the following on Python 2.4/Linux 2.6.8, so it does
seem to be fixed:

>>> from re import compile
>>> line = ""
>>> pat = compile(12 * r'(\d+)')
>>> ltarget = float(pat.sub(r'\10',line))
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
ValueError: empty string for float()

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Comment By: Fredrik Lundh (effbot)
Date: 2004-11-02 13:00

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If you need a workaround for 2.2, use a sub callback:

http://effbot.org/zone/re-sub.htm#callbacks

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Comment By: Fredrik Lundh (effbot)
Date: 2004-11-02 12:58

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Cannot check this right now, but I'm 99% sure that this has 
been fixed in 2.4.

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