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bug#8915: 23.3; Repeatable segmentation fault, all platforms, in charact
bug#8915: 23.3; Repeatable segmentation fault, all platforms, in character composition code
Thu, 07 Jul 2011 15:02:32 +0900
I'm very sorry for the late response.
In article <address@hidden>, YAMAMOTO Mitsuharu <address@hidden> writes:
>>>>>> On Tue, 21 Jun 2011 17:04:57 +0100, David Aspinall <address@hidden> said:
> > There is a segfault which arises reproducibly when compose-character is
> > used near the end of a buffer. I'm afraid I don't have a raw test case
> > but here is a recipe to reproduce it that loads the Emacs application
> > Proof General:
> > wget http://proofgeneral.inf.ed.ac.uk/releases/ProofGeneral-4.0.tgz
> > tar -xpzf ProofGeneral-4.0.tgz
> > (cd ProofGeneral; make clean)
> > emacs -q -l ProofGeneral/generic/proof-site.el
> > C-x C-f Test.thy
> > Then type
> > \<forall>
> > and Emacs segfaults. If instead you type
> > M-x 1 0 SPACE C-a \<forall>
> > it behaves as expected: looks like the code is running off the end of
> > the buffer.
> At least, the following change seems to avoid the crash. But I'm not
> sure if this is a right fix at all.
> Handa-san, could you take a look at this issue? The problematic case
> is that the addition of the `composite' property via fontification
> occurs during redisplay and the composition is found in the middle of
> the composed region. That happens if the first part of the region had
> a non-nil `fontified' property and the second part did not, and then
> fontification-functions added the `composite' property to the whole
Could you please try the attached patch which, I think, is
cleaner. It simply ignores a composition added by font-lock
at the first time. The next redisplay will finds that
composition at earlier position (i.e. the starting position
of the composition), and thus handles it correctly.
=== modified file 'src/ChangeLog'
--- src/ChangeLog 2011-06-18 00:37:38 +0000
+++ src/ChangeLog 2011-07-07 05:53:06 +0000
@@ -1,3 +1,10 @@
+2011-07-07 Kenichi Handa <address@hidden>
+ * composite.c (composition_compute_stop_pos): Ignore a static
+ composition starting before CHARPOS.
+ * xdisp.c (handle_composition_prop): Likewise.
2011-06-18 YAMAMOTO Mitsuharu <address@hidden>
* dispnew.c (scrolling_window): Before scrolling, turn off a
=== modified file 'src/composite.c'
--- src/composite.c 2011-05-09 09:59:23 +0000
+++ src/composite.c 2011-07-07 05:47:54 +0000
@@ -1042,6 +1042,7 @@
cmp_it->id = -1;
cmp_it->ch = -2;
if (find_composition (charpos, endpos, &start, &end, &prop, string)
+ && start >= charpos
&& COMPOSITION_VALID_P (start, end, prop))
cmp_it->stop_pos = endpos = start;
=== modified file 'src/xdisp.c'
--- src/xdisp.c 2011-05-25 03:06:05 +0000
+++ src/xdisp.c 2011-07-06 08:13:42 +0000
@@ -4641,6 +4641,11 @@
&& COMPOSITION_VALID_P (start, end, prop)
&& (STRINGP (it->string) || (PT <= start || PT >= end)))
+ if (start < pos)
+ /* As we can't handle this situation (perhaps, font-lock added
+ a new composition), we just return here hoping that next
+ redisplay will detect this composition much earlier. */
+ return HANDLED_NORMALLY;
if (start != pos)
if (STRINGP (it->string))
- bug#8915: 23.3; Repeatable segmentation fault, all platforms, in character composition code,
Kenichi Handa <=