GNU bug report logs - #57245
29.0.50; M-> in a large XML file (without long lines) is slow

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Package: emacs;

Reported by: Dmitry Gutov <dgutov <at> yandex.ru>

Date: Tue, 16 Aug 2022 14:35:02 UTC

Severity: normal

Found in version 29.0.50

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From: Eli Zaretskii <eliz <at> gnu.org>
To: Dmitry Gutov <dgutov <at> yandex.ru>
Cc: 57245 <at> debbugs.gnu.org, monnier <at> iro.umontreal.ca
Subject: bug#57245: 29.0.50; M-> in a large XML file (without long lines) is slow
Date: Wed, 17 Aug 2022 15:20:56 +0300
> Date: Wed, 17 Aug 2022 15:14:07 +0300
> Cc: 57245 <at> debbugs.gnu.org, monnier <at> iro.umontreal.ca
> From: Dmitry Gutov <dgutov <at> yandex.ru>
> 
> >> Which seems to be exactly the behavior the "font-lock narrowing" was
> >> supposed to guard from?
> > 
> > No.  It wasn't supposed to fix modes that foolishly scan the buffer
> > from BOB to point.
> 
> You might want to choose words better.

I did.

> > It was supposed to fix modes which scan from the
> > beginning of line, and that is (a) only a problem when lines are very
> > long, and (b) much harder to solve in the mode itself, because
> > font-lock very frequently uses anchored regexps and otherwise likes to
> > start from BOL, and syntax processing also likes starting from BOL.
> 
> syntax-wholelines-max handles that problem.

Only for syntax-related stuff.  And we have yet to see whether it's a
good enough job: that feature is too young to be sure.




This bug report was last modified 2 years and 304 days ago.

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