From: "Mattias Engdegård" <mattiase@acm.org>
To: 34823@debbugs.gnu.org
Subject: bug#34823: 27.0.50; re-search-forward infloop
Date: Fri, 29 Mar 2019 14:28:18 +0100 [thread overview]
Message-ID: <B5915A5D-14EB-47F6-99EC-26AD8C7C7D5E@acm.org> (raw)
In-Reply-To: <87y35kqse3.fsf@gmail.com>
It is not actually an infinite loop; it just takes a very long time.
Your case is, more or less, essentially
(search-string "\\(?:a*\\)*b" "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
Try trimming the string, and you will see that the match does terminate (and fail); it is just super-linear in the length of the text.
This is a shortcoming of the general type of regexp engine used by Emacs.
To work around your problem, you should make the regexp less prone to backtracking. Try asking on the list help-gnu-emacs@gnu.org for advice. Describe what text you wish to match as precisely as possible.
prev parent reply other threads:[~2019-03-29 13:28 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-12 10:49 bug#34823: 27.0.50; re-search-forward infloop Vitalie Spinu
2019-03-29 13:28 ` Mattias Engdegård [this message]
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