GNU bug report logs - #61514
30.0.50; sadistically long xml line hangs emacs

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Package: emacs;

Reported by: "Mark A. Hershberger" <mah <at> everybody.org>

Date: Tue, 14 Feb 2023 21:05:02 UTC

Severity: normal

Found in version 30.0.50

Done: Gregory Heytings <gregory <at> heytings.org>

Bug is archived. No further changes may be made.

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From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Gregory Heytings <gregory <at> heytings.org>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 61514 <at> debbugs.gnu.org, mah <at> everybody.org
Subject: bug#61514: 30.0.50; sadistically long xml line hangs emacs
Date: Mon, 20 Feb 2023 09:16:15 -0500
>> And for the stack overflow I haven't yet found its origin.
> There is no stack overflow here, AFAIU.  It's simply that the prepended
> regexp matches one or more (without any upper bound) characters except
> "<>\n", which means that we backtrack _a lot_ when the line is long.

There is clearly a stack overflow since the OP showed stack overflow
errors in *Messages*.

And the stack overflow is in the rest of the regexp: the `+?` repetition
uses only ever 1 stack slot no matter how long a match we consider
(contrary to the `+` and `*` repetitions which use N stack slots for the
N repetitions of the longest match).


        Stefan





This bug report was last modified 2 years and 147 days ago.

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