Subject: 24.0.50; bidi aborts: "can't happen" happens
From: Ari Roponen <[email-masked]>
To: [email-masked]
Date: Thu, 08 Apr 2010 12:03:55 +0300
List-Id: <debbugs-submit.debbugs.gnu.org>

Hi,

the following code crashes emacs by making code in bidi.c call
abort():

  (let ((bidi-display-reordering t))
    (insert #x650 #x650)		; ARABIC KASRA
    (redisplay))

The place that calls abort() is in bidi_resolve_neutral():

#0  abort () at emacs.c:430
#1  0x0000000000490abe in bidi_resolve_neutral (bidi_it=0x7fffffff9000)
    at bidi.c:1577
#2  0x000000000049119a in bidi_level_of_next_char (bidi_it=0x7fffffff9000)
    at bidi.c:1713
...

(gdb) up
#1  0x0000000000490abe in bidi_resolve_neutral (bidi_it=0x7fffffff9000)
    at bidi.c:1577
1577			  abort ();		/* can't happen: BNs are skipped */
(gdb) l
1572			next_type = STRONG_R;
1573			saved_it.next_for_neutral.type = STRONG_R;
1574			break;
1575		      case WEAK_BN:
1576			if (!bidi_explicit_dir_char (bidi_it->ch))
1577			  abort ();		/* can't happen: BNs are skipped */
1578			/* FALLTHROUGH */
1579		      case NEUTRAL_B:
1580			/* Marched all the way to the end of this level run.
1581			   We need to use the eor type, whose information is

In GNU Emacs 24.0.50.3 (x86_64-unknown-linux-gnu, GTK+ Version 2.19.7)
 of 2010-04-07 on arirop
Windowing system distributor `Fedora Project', version 11.0.10799901

-- 
Ari Roponen