Broken pre.subn() (and pre.sub())

[tuben]

BPO	570057

^{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 2002-06-27.20:19:52.000>
created_at = <Date 2002-06-17.14:27:33.000>
labels = ['expert-regex']
title = 'Broken pre.subn() (and pre.sub())'
updated_at = <Date 2002-06-27.20:19:52.000>
user = 'https://bugs.python.org/tuben'

bugs.python.org fields:

activity = <Date 2002-06-27.20:19:52.000>
actor = 'effbot'
assignee = 'effbot'
closed = True
closed_date = None
closer = None
components = ['Regular Expressions']
creation = <Date 2002-06-17.14:27:33.000>
creator = 'tuben'
dependencies = []
files = []
hgrepos = []
issue_num = 570057
keywords = []
message_count = 3.0
messages = ['11229', '11230', '11231']
nosy_count = 2.0
nosy_names = ['effbot', 'tuben']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue570057'
versions = ['Python 2.2']

[tuben]

The functions pre.subn() and pre.sub() are broken in
Python2.2 and 2.2.1. The following test was done on
SunOS 5.6:

Python 2.2.1 (#1, Jun 13 2002, 12:57:34) 
[GCC 2.95.2 19991024 (release)] on sunos5
Type "help", "copyright", "credits" or "license" for
more information.
>>> import re
>>> re.sub('(a)', '\g<1>', 'bab')
'bab'
>>> import pre as re
>>> re.sub('(a)', '\g<1>', 'bab')
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/local/tools/lib/python2.2/pre.py", line
179, in sub
    return pattern.sub(repl, string, count)
  File "/usr/local/tools/lib/python2.2/pre.py", line
344, in sub
    return self.subn(repl, string, count)[0]
  File "/usr/local/tools/lib/python2.2/pre.py", line
366, in subn
    repl = pcre_expand(_Dummy, repl)
TypeError: 'NoneType' object is not callable

The error has also been reproduced on SunOS5.7 with the
following interpreter:
Python 2.2 (#1, Dec 28 2001, 22:25:04)
[GCC 2.95.2 19991024 (release)] on sunos5

The error could not be reproduced on SunOS5.6 using
Python2.1.1:
Python 2.1.1 (#5, Sep 10 2001, 13:44:17)
[GCC 2.95.2 19991024 (release)] on sunos5

NOTE: The example for re.sub() in the Python Library
manual triggers this bug when used with module pre!

[effbot]

Logged In: YES
user_id=38376

someone who didn't understand the code changed an
"except" to "except error", and the test suite doesn't
spend much energy checking that PRE works as it
should... :-(

(as a workaround, change the line after the "pcre_expand"
call to "except:")

</F>

[effbot]

Logged In: YES
user_id=38376

fixed in CVS