helpRegular Expressions for Java - Support: sr #105180, Some regexes lead to infinite loop


sr #105180: Some regexes lead to infinite loop

Submitted by:  None
Submitted on:  Wed 22 Feb 2006 10:07:57 PM UTC  
Category:  None Priority:  5 - Normal
Severity:  5 - Blocker Status:  None
Privacy:  Public Assigned to:  None
Originator Email:  -email is unavailable- Open/Closed:  Open
Operating System:  Microsoft Windows

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Wed 22 Feb 2006 10:07:57 PM UTC, original submission:

I ran across a regex that, if run using substituteAll(), will result in an infinite loop for some reason. The regex is below, and has only been modified slightly to hide my company's info. The regex is used to strip off some personal information from incoming email replies we receive, and is very "fuzzy" to account for how email clients can really screw with the text. The regex is:

new RE("This.{0,10}?email.{0,10}?is.{0,10}?for.{0,10}?registered.{0,10}?members.{0,10}?of.{0,10}?OurSite.{0,10}?only[^\\.]*\\..{0,10}You.{0,10}?joined.{0,10}?OurSite.{0,10}?under.{0,10}?the.{0,10}?name.*?on.{0,10}?\\d+/\\d+/\\d+[^\\.]*\\..{0,10}You.{0,10}?can.{0,10}?turn.{0,10}?this.{0,10}?email.{0,10}?off.{0,10}?from.{0,10}?the.{0,10}?links.{0,10}?at.{0,10}?the.{0,10}?bottom.{0,10}?of.{0,10}?this.{0,10}?message[^\\.]*\\.?

It will usually work fine. But we received an email today that contained the following text, which when run against this regex, resulted in an infinite loop (notice the message text is cut off before the end of the regex would have matched):

Date: Tue, 21 Feb 2006 21:08:04 -0800 (PST)
From: -email is unavailable-
Subject: Yahoo! Auto Response
To: OurSite <>
MIME-Version: 1.0
Content-Type: text/plain

This email is for registered members of OurSite only. You joined
OurSite under the name Joe Smith on 11/29/2000. You can turn
this email off from the links at the bottom of this mes



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Follows 1 latest change.

Date Changed by Updated Field Previous Value => Replaced by
Wed 22 Feb 2006 10:07:57 PM UTC None Carbon-Copy- => Added nospam --AT-- thanks --DOT-- com

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