From: Alan Mackenzie <acm@muc.de>
To: Eli Zaretskii <eliz@gnu.org>
Cc: psainty@orcon.net.nz, gerd.moellmann@gmail.com,
Gregory Heytings <gregory@heytings.org>,
59038@debbugs.gnu.org, checker@d6.com
Subject: bug#59038: loading this base64 file makes emacs -Q 28.2 peg a core infinitely
Date: Sun, 6 Nov 2022 16:34:57 +0000 [thread overview]
Message-ID: <Y2fiMTlfuNqae7zp@ACM> (raw)
In-Reply-To: <83iljs197i.fsf@gnu.org>
Hello, Eli.
On Sun, Nov 06, 2022 at 15:52:33 +0200, Eli Zaretskii wrote:
> > Date: Sun, 06 Nov 2022 09:18:23 +0000
> > From: Gregory Heytings <gregory@heytings.org>
> > cc: Eli Zaretskii <eliz@gnu.org>,
> > Gerd Möllmann <gerd.moellmann@gmail.com>,
> > 59038@debbugs.gnu.org, checker@d6.com, acm@muc.de
> > >> That file opens just fine in other modes
> > > It also opens fine in c-mode, with global-font-lock-mode disabled.
> > Indeed, obviously it's a c-mode font-locking related bug.
> > >> Note that this bug has nothing to do with long lines.
> > > I imagine that the font-lock issue is related to the line being in
> > > excess of 21,000 chars (but general redisplay obviously doesn't have
> > > problems with lines this 'small').
> > > Reduced to 10,208 chars that file opens instantly under emacs -Q in
> > > c-mode with font-lock enabled; but at 10,209 chars it hangs Emacs (I
> > > killed it after waiting 4 minutes).
> > Interesting, thanks for the bisection!
> It's an infloop in c-brace-stack-at.
> What happens is that c-brace-stack-at calls c-update-brace-stack with
> arguments: (nil 1) 8160 13160. c-update-brace-stack then calls
> c-syntactic-re-search-forward, which finds nothing interesting and
> returns with point at 13160, but then c-update-brace-stack calls
> c-beginning-of-current-token, which returns point back to 8160. And
> it goes on and on and on...
Thanks for the debugging.
> Alan, what can be done with this?
This:
diff -r 53717eda724c cc-engine.el
--- a/cc-engine.el Sat Oct 29 09:42:47 2022 +0000
+++ b/cc-engine.el Sun Nov 06 16:26:09 2022 +0000
@@ -6177,9 +6177,10 @@
(setq s (cdr s))))
((c-keyword-member kwd-sym 'c-flat-decl-block-kwds)
(push 0 s))))
- ;; The failing `c-syntactic-re-search-forward' may have left us in the
- ;; middle of a token, which might be a significant token. Fix this!
- (c-beginning-of-current-token)
+ (when (> prev-match-pos 1) ; Has the search matched at least once?
+ ;; The failing `c-syntactic-re-search-forward' may have left us in the
+ ;; middle of a token, which might be a significant token. Fix this!
+ (c-beginning-of-current-token))
(cons (point)
(cons bound-<> s)))))
--
Alan Mackenzie (Nuremberg, Germany).
next prev parent reply other threads:[~2022-11-06 16:34 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-05 2:48 bug#59038: loading this base64 file makes emacs -Q 28.2 peg a core infinitely Chris Hecker
2022-11-05 5:12 ` Gerd Möllmann
2022-11-05 7:01 ` Eli Zaretskii
2022-11-05 7:50 ` Gerd Möllmann
2022-11-05 8:21 ` Chris Hecker
2022-11-05 8:45 ` Gerd Möllmann
2022-11-05 9:30 ` Eli Zaretskii
2022-11-05 10:39 ` bug#59038: Re[2]: " Chris Hecker
2022-11-05 11:29 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-11-05 15:01 ` Chris Hecker
2022-11-06 5:17 ` Gerd Möllmann
2022-11-05 22:03 ` Alan Mackenzie
2022-11-06 6:00 ` Eli Zaretskii
2022-11-05 9:28 ` Eli Zaretskii
2022-11-06 5:18 ` Gerd Möllmann
2022-11-05 22:27 ` Gregory Heytings
2022-11-05 23:41 ` Gregory Heytings
2022-11-06 3:58 ` Phil Sainty
2022-11-06 5:20 ` Gerd Möllmann
2022-11-06 13:54 ` Alan Mackenzie
2022-11-06 9:18 ` Gregory Heytings
2022-11-06 13:52 ` Eli Zaretskii
2022-11-06 16:34 ` Alan Mackenzie [this message]
2022-11-07 7:55 ` Gerd Möllmann
[not found] ` <Y2fiMTlfuNqae7zp@acm>
2022-11-06 19:46 ` bug#59038: Re[2]: " Chris Hecker
2022-11-07 12:25 ` Alan Mackenzie
2022-11-05 6:52 ` Eli Zaretskii
2022-11-05 10:45 ` Phil Sainty
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