[issue13723] Regular expressions: (?:X|\s+)*$ takes a long time

[Eric Promislow]

New submission from Eric Promislow <ericp at activestate.com>:

This regular expression takes a few seconds to be evaluated
against any text:

(.*?)((?:X|\s+)*)$

This reg ex is much faster:

(.*?)((?:X|\s)*)$

To be fair, Ruby's performance with the first regex is the same as Python's. PHP and JavaScript both fail to match the first regex
at all.  Only Perl evaluates both regexes nearly instantly.

----------
messages: 150770
nosy: ericp
priority: normal
severity: normal
status: open
title: Regular expressions: (?:X|\s+)*$ takes a long time
type: performance
versions: Python 2.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue13723>
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