bug#4342: 23.1; smerge-next marks buffer as modified

[Tom Tromey]

Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your bug report will be posted to the bug-gnu-emacs@gnu.org mailing list,
and to the gnu.emacs.bug news group.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:


I did a cvs update and had some conflicts.

I visited a file with a conflict and typed M-x smerge-mode.

Then I did C-c ^ n (smerge-next) to go to the first conflict.

This marked my buffer as modified.
AFAICT, though, nothing actually changed.

I think simply moving between conflicts should not modify the buffer.


If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
If you would like to further debug the crash, please read the file
/usr/share/emacs/23.1/etc/DEBUG for instructions.


In GNU Emacs 23.1.1 (i386-redhat-linux-gnu, GTK+ Version 2.16.5)
 of 2009-08-24 on x86-2.fedora.phx.redhat.com
Windowing system distributor `The X.Org Foundation', version 11.0.10601901
configured using `configure  '--build=i386-redhat-linux-gnu' 
'--host=i386-redhat-linux-gnu' '--target=i586-redhat-linux-gnu' 
'--program-prefix=' '--prefix=/usr' '--exec-prefix=/usr' '--bindir=/usr/bin' 
'--sbindir=/usr/sbin' '--sysconfdir=/etc' '--datadir=/usr/share' 
'--includedir=/usr/include' '--libdir=/usr/lib' '--libexecdir=/usr/libexec' 
'--localstatedir=/var' '--sharedstatedir=/var/lib' '--mandir=/usr/share/man' 
'--infodir=/usr/share/info' '--with-dbus' '--with-gif' '--with-jpeg' 
'--with-png' '--with-rsvg' '--with-tiff' '--with-xft' '--with-xpm' 
'--with-x-toolkit=gtk' 'build_alias=i386-redhat-linux-gnu' 
'host_alias=i386-redhat-linux-gnu' 'target_alias=i586-redhat-linux-gnu' 
'CFLAGS=-DMAIL_USE_LOCKF -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 
-fexceptions -fstack-protector --param=ssp-buffer-size=4 -m32 -march=i586 
-mtune=generic -fasynchronous-unwind-tables''

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: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Change Log

Minor modes in effect:
  shell-dirtrack-mode: t
  diff-auto-refine-mode: t
  auto-fill-function: do-auto-fill
  erc-list-mode: t
  erc-menu-mode: t
  erc-autojoin-mode: t
  erc-ring-mode: t
  erc-pcomplete-mode: t
  erc-track-mode: t
  erc-track-minor-mode: t
  erc-match-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  erc-netsplit-mode: t
  erc-spelling-mode: t
  erc-truncate-mode: t
  flyspell-mode: t
  erc-status-mode: t
  erc-services-mode: t
  erc-networks-mode: t
  erc-irccontrols-mode: t
  erc-noncommands-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
y C-u C-n n n n n n n SPC M-> q SPC M-> q SPC 5 0 <return> 
M-> q C-l s C-r o t h e r C-a SPC 5 0 <return> M-> 
C-u C-u C-p C-u C-p C-p p Q y s C-z o <f10> <f10> <f10> 
<f10> C-c b <f10> <switch-frame> C-z n <f10> <f10> 
<f10> <f10> <f10> <f10> <f10> <f10> M-v M-> <f10> <switch-frame> 
<switch-frame> C-z o C-u C-u C-n p p SPC 5 0 <return> 
M-> q s C-z o <f10> C-z o M-v C-l M-g M-g M-g M-g M-g 
p SPC C-u C-n C-u d C-p C-p SPC q s C-u C-n p SPC M-> 
q s C-z n <f10> <f10> C-z o M-v M-v M-< M-g M-g M-g 
M-g p SPC SPC q s C-u C-n C-u C-n C-u C-n C-p C-p C-p 
M-g M-g M-g M-g s C-z o <f10> <f10> C-z o C-u C-u C-n 
p M-g M-g M-g M-g s C-f C-z o <f10> <f10> <switch-frame> 
C-z n <f10> <f10> <switch-frame> <switch-frame> <f10> 
<f10> <f10> C-x C-f C h <tab> <return> y e s <return> 
C-a C-p C-p C-p C-SPC C-u C-u C-n C-n C-n C-n C-n C-w 
M-< C-y C-c a C-p C-p C-f C-f C-SPC C-u C-n C-w C-x 
C-s n C-z o C-x C-f M-p <M-backspace> d w <tab> l o 
<tab> c <return> y e s <return> C-s < < < < < C-a M-< 
M-x s m e r g e - m o d e <return> C-c ^ n C-v C-v 
C-v C-v C-s C-s C-s C-a C-/ C-h c C-c ^ n C-c ^ n C-c 
^ p C-l C-/ M-< C-c ^ n C-z o M-x e <backspace> r e 
p o r t - e m <tab> b <tab> <return>

Recent messages:
Wrote /home/tromey/gnu/baseline-gdb/src/gdb/ChangeLog
Mark saved where search started
Mark set
Smerge mode enabled
Mark saved where search started
Undo!
C-c ^ n runs the command smerge-next
Undo!
Mark set
C-c ^ n runs the command smerge-next
Quit
Tom