Subject: previous-line stays put, and next-line crashes

From: Stefan Monnier <[email-masked]>
Date: Fri, 05 Aug 2011 11:10:45 -0400

Not sure if the two are related (I only bumped into the crash today
while creating the recipe for this bug-report), but here it goes.
Create the file foo.ll attached (see below) and then

   % emacs -Q ~/tmp/foo.ll
   [ accept the file-local settings ]
   M->
   C-p C-p C-p

I notice 3 problems:
- After the first C-p the cursor is drawn on the second "\n" of the
  "¶\n\n" display property.  In Emacs-23, the cursor was drawn on the
  "¶".  Not sure if it's longlines-mode which should add a `cursor'
  property, but at least that's a change in behavior w.r.t Emacs-23.
- On the second (and third) C-p, the cursor fails to move.
  AFAICT this bug was already present in Emacs-23.
- If I then hit C-n, I get a crash with the backtrace appended after
  my sig.  I.e. bidi_cache_start is zero upon entry to bidi_pop_it.

        Stefan

#0  abort () at emacs.c:380
#1  0x0817c35a in bidi_pop_it (bidi_it=0xbfffd598) at bidi.c:605
#2  0x08094f82 in pop_it (it=0xbfffcfe0) at xdisp.c:5425
#3  0x080997f6 in set_iterator_to_next (it=0xbfffcfe0, reseat_p=1)
    at xdisp.c:6796
#4  0x0809da7d in move_it_to (it=0xbfffcfe0, to_charpos=-1, to_x=-1, to_y=-1, 
    to_vpos=1, op=4) at xdisp.c:8315
#5  0x0809e475 in move_it_by_lines (it=0xbfffcfe0, dvpos=1) at xdisp.c:8610
#6  0x082e76af in Fvertical_motion (lines=..., window=...) at indent.c:2095
#7  0x083422c0 in Ffuncall (nargs=2, args=0xbfffd9a0) at eval.c:3012
#8  0x083bb78f in exec_byte_code (bytestr=..., vector=..., maxdepth=..., 
    args_template=..., nargs=0, args=0x0) at bytecode.c:785
#9  0x08343545 in funcall_lambda (fun=..., nargs=2, arg_vector=0x5)
    at eval.c:3240
#10 0x08342708 in Ffuncall (nargs=3, args=0xbfffdd40) at eval.c:3058
#11 0x083bb78f in exec_byte_code (bytestr=..., vector=..., maxdepth=..., 
    args_template=..., nargs=0, args=0x0) at bytecode.c:785
#12 0x08343545 in funcall_lambda (fun=..., nargs=4, arg_vector=0x4)
    at eval.c:3240
#13 0x08342708 in Ffuncall (nargs=5, args=0xbfffe0d0) at eval.c:3058
#14 0x083bb78f in exec_byte_code (bytestr=..., vector=..., maxdepth=..., 
    args_template=..., nargs=0, args=0x0) at bytecode.c:785
#15 0x083ba9d6 in Fbyte_code (bytestr=..., vector=..., maxdepth=...)
    at bytecode.c:423
#16 0x0833fd0b in eval_sub (form=...) at eval.c:2363
#17 0x0833cef1 in internal_lisp_condition_case (var=..., bodyform=..., 
    handlers=...) at eval.c:1440
#18 0x083bc489 in exec_byte_code (bytestr=..., vector=..., maxdepth=..., 
    args_template=..., nargs=0, args=0x0) at bytecode.c:981
#19 0x08343545 in funcall_lambda (fun=..., nargs=2, arg_vector=0x6)
    at eval.c:3240
#20 0x08342708 in Ffuncall (nargs=3, args=0xbfffe980) at eval.c:3058
#21 0x083385c4 in Fcall_interactively (function=..., record_flag=..., 
    keys=...) at callint.c:857
#22 0x08342347 in Ffuncall (nargs=4, args=0xbfffec74) at eval.c:3016
#23 0x083415a5 in call3 (fn=..., arg1=..., arg2=..., arg3=...) at eval.c:2809
#24 0x0827cc0d in Fcommand_execute (cmd=..., record_flag=..., keys=..., 
    special=...) at keyboard.c:10274
#25 0x0825c2a5 in command_loop_1 () at keyboard.c:1572
#26 0x0833d028 in internal_condition_case (bfun=0x825b048 <command_loop_1>, 
    handlers=..., hfun=0x825a690 <cmd_error>) at eval.c:1493
#27 0x0825abdf in command_loop_2 (ignore=...) at keyboard.c:1156
#28 0x0833c826 in internal_catch (tag=..., func=0x825abb3 <command_loop_2>, 
    arg=...) at eval.c:1247
#29 0x0825ab88 in command_loop () at keyboard.c:1135
#30 0x08259f82 in recursive_edit_1 () at keyboard.c:756
#31 0x0825a322 in Frecursive_edit () at keyboard.c:820
#32 0x08257a6e in main (argc=3, argv=0xbffff554) at emacs.c:1705

Lisp Backtrace:
"vertical-motion" (0xbfffd9a4)
"line-move-visual" (0xbfffdd44)
"line-move" (0xbfffe0d4)
"byte-code" (0xbfffe388)
"next-line" (0xbfffe984)
"call-interactively" (0xbfffec78)

toto asdfkjsahfd dkjafkjfkja ffffgkusa gfksaj gksa ga gygfoiesa goiue goiea glicvlkjfa lekfgaruqpif gfliagflka b;alkjnhleshua;wo h
w hffgoiw gfaoiwf goiw gfoiw fgowqigoiwyf goiwqgoiwf gwqoiugf wqoiuf
guf poiwqgoi gwoifgqoiw gf oiwfg oiwqw hffgoiw gfaoiwf goiw gfoiw fgowqigoiwyf goiwqgoiwf gwqoiugf wqoiuf guf poiwqgoi gwoifgqoiw gf oiwfg oiwqw hffgoiw gfaoiwf goiw gfoiw fgowqigoiwyf goiwqgoiwf gwqoiugf wqoiuf guf poiwqgoi gwoifgqoiw gf oiwfg oiwqw hffgoiw gfaoiwf goiw gfoiw fgowqigoiwyf goiwqgoiwf gwqoiugf wqoiuf

guf poiwqgoi gwoifgqoiw gf oiwfg oiwqw hffgoiw gfaoiwf goiw gfoiw fgowqigoiwyf goiwqgoiwf gwqoiugf wqoiuf guf poiwqgoi gwoifgqoiw gf oiwfg oiwqw hffgoiw gfaoiwf goiw gfoiw fgowqigoiwyf goiwqgoiwf gwqoiugf wqoiuf guf poiwqgoi gwoifgqoiw gf oiwfg oiwqw hffgoiw gfaoiwf goiw gfoiw fgowqigoiwyf goiwqgoiwf gwqoiugf wqoiuf guf poiwqgoi gwoifgqoiw gf oiwfg oiwqw hffgoiw gfaoiwf goiw gfoiw fgowqigoiwyf goiwqgoiwf gwqoiugf wqoiuf guf poiwqgoi gwoifgqoiw gf oiwfg oiwqg

# Local Variables:
# longlines-show-effect: "¶\n\n"
# longlines-show-hard-newlines: t
# mode: longlines
# End: 

In GNU Emacs 24.0.50.1 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2011-08-04 on ceviche
Windowing system distributor `The X.Org Foundation', version 11.0.11002000
configured using `configure  'CFLAGS=-Wall -Wno-pointer-sign -DUSE_LISP_UNION_TYPE -DSYNC_INPUT -DENABLE_CHECKING -DXASSERTS -DFONTSET_DEBUG -g -O1 -I/usr/include/GNUstep' '--enable-maintainer-mode' '--with-x-toolkit=lucid''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: fr_CH.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: InactiveMinibuffer

Minor modes in effect:
  diff-auto-refine-mode: t
  shell-dirtrack-mode: t
  electric-pair-mode: t
  electric-indent-mode: t
  url-handler-mode: t
  global-reveal-mode: t
  reveal-mode: t
  auto-insert-mode: t
  savehist-mode: t
  minibuffer-electric-default-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<mouse-movement> <mouse-1> C-l C-a <up> <up> <up> <up> 
<up> <up> <right> <right> <right> <right> <right> <right> 
<right> <right> <C-up> <up> <left> <right> <down> <left> 
<right> <up> <left> <right> <return> <up> C-/ <up> 
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> <up> 
<up> <left> <right> <down> <left> <right> <left> <down> 
<right> <left> <down> <right> <down> <left> <right> 
<down> <left> <right> <down> <left> <right> <down> 
<left> <right> <down> <left> <right> <down> <left> 
<right> <down> <left> <right> <down> <left> <right> 
<left> <down> <right> <left> <down> <right> <down> 
<left> <right> <down> <left> <right> <up> <left> <right> 
<up> <left> <right> C-s C-s C-s C-r C-r C-s C-s C-r 
C-r <right> <right> <right> <help-echo> <switch-frame> 
<help-echo> <switch-frame> <switch-frame> <help-echo> 
<help-echo> <switch-frame> <switch-frame> <switch-frame> 
<switch-frame> <help-echo> <switch-frame> <help-echo> 
<switch-frame> <switch-frame> <switch-frame> <switch-frame> 
<switch-frame> <switch-frame> <switch-frame> <switch-frame> 
<switch-frame> <switch-frame> <switch-frame> C-x 5 
f <M-backspace> <M-backspace> <M-backspace> <M-backspace> 
<M-backspace> e / e / e <tab> <return> C-s l o n g 
l i C-a C-e <right> C-e <right> <switch-frame> <switch-frame> 
<switch-frame> <switch-frame> <help-echo> <down-mouse-1> 
<mouse-1> C-e <left> <left> <left> <M-backspace> <M-backspace> 
<backspace> <help-echo> <backspace> C-a <right> <right> 
<right> <right> C-M-SPC M-w <switch-frame> <switch-frame> 
C-M-SPC M-w <switch-frame> <switch-frame> C-x 5 f c 
u s <tab> <return> C-s l o n g <left> <left> <left> 
<left> h <switch-frame> <switch-frame> <switch-frame> 
<switch-frame> C-/ <switch-frame> <switch-frame> <switch-frame> 
C-a C-k C-s C-s C-s C-a <switch-frame> <switch-frame> 
<switch-frame> <down> C-y <up> C-d C-d <right> s e 
t q SPC C-a C-x C-s <switch-frame> <switch-frame> <switch-frame> 
<switch-frame> <switch-frame> <switch-frame> <right> 
<right> <right> <right> <right> <right> <right> <left> 
C-M-SPC M-w <switch-frame> <switch-frame> <switch-frame> 
<help-echo> <switch-frame> <switch-frame> <switch-frame> 
<switch-frame> <switch-frame> <switch-frame> <switch-frame> 
<switch-frame> <down> <switch-frame> <switch-frame> 
<switch-frame> <switch-frame> <switch-frame> <switch-frame> 
<switch-frame> <switch-frame> <switch-frame> <switch-frame> 
<help-echo> <switch-frame> <switch-frame> <switch-frame> 
M-x r e p o - e m - u <switch-frame> <backspace> b 
<switch-frame> <backspace> b <tab> <return>

Recent messages:
Warning: interactive-p is obsolete!
Mark set
Mark saved where search started
Undo!
Mark set
Saving file /home/monnier/share/etc/emacs/emacs.el...
Wrote /home/monnier/share/etc/emacs/emacs.el
Mark set
Warning: interactive-p is obsolete!
Undo! [2 times]

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