From: storm@cua.dk (Kim F. Storm)
Cc: emacs-devel@gnu.org
Subject: Re: Mysterious redisplay problem and a trap in xdisp.c
Date: 10 Feb 2002 00:06:16 +0100 [thread overview]
Message-ID: <5xzo2i45nb.fsf@kfs2.cua.dk> (raw)
In-Reply-To: <86aduigtvc.fsf@gerd.dnsq.org>
gerd.moellmann@t-online.de (Gerd Moellmann) writes:
> storm@cua.dk (Kim F. Storm) writes:
>
>
> [...]
>
> > I have now tracked the problem down to the following change:
> >
> > 2001-12-11 Andrew Innes <andrewi@gnu.org>
> >
> > * insdel.c (make_gap) [DOUG_LEA_MALLOC]: Call make_gap_smaller if
> > arg is negative.
> >
> > If I comment out the call to make_gap_smaller in make_gap, the problem
> > goes away!
>
> Hm, my theory, which might well be completely wrong, would be that a GC
> during redisplay, via make_gap_smaller, changes the address of the
> characters to be displayed, and that some code in redisplay doesn't
> protect itself against that address change.
I did some more digging, and discovered that make_gap_smaller does not
preserves the value of BEG_UNCHANGED around the gap manipulation.
In most cases, it will have moved that offset *ahead* in the buffer -
i.e. redisplay does not look for buffer changes at the place where it
actually happened... Why that results in inserting a newline I don't
know - or whether it can explain the traps/aborts I've seen.
In any case, I just committed a fix to restore BEG_UNCHANGED after the
gap reduction, and it seems to have fixed the problem.
--
Kim F. Storm <storm@cua.dk> http://www.cua.dk
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next prev parent reply other threads:[~2002-02-09 23:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-02-09 20:59 Mysterious redisplay problem and a trap in xdisp.c Kim F. Storm
2002-02-09 22:42 ` Gerd Moellmann
2002-02-09 23:06 ` Kim F. Storm [this message]
2002-02-11 2:09 ` Richard Stallman
2002-02-11 8:27 ` Kim F. Storm
-- strict thread matches above, loose matches on Subject: below --
2002-02-07 12:59 Kim F. Storm
2002-02-07 19:47 ` Eli Zaretskii
2002-02-08 13:57 ` Richard Stallman
2002-02-08 20:50 ` Kim F. Storm
2002-02-09 7:25 ` Eli Zaretskii
2002-02-10 5:17 ` Richard Stallman
2002-02-11 2:09 ` Richard Stallman
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