bug#11960: Defective layout change on M-x ediff-buffers

bug#11960: Defective layout change on M-x ediff-buffers

[Marius Hofert]

This bug report will be sent to the Bug-GNU-Emacs mailing list
and the GNU bug tracker at debbugs.gnu.org.  Please check that
the From: line contains a valid email address.  After a delay of up
to one day, you should receive an acknowledgement at that address.

Please write in English if possible, as the Emacs maintainers
usually do not have translators for other languages.

Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':

1) start emacs via emacs -Q
2) open a buffer A
3) use C-x 3 to open another buffer (buffer B) next to A (side-by-side)
4) use M-x ediff-buffers to compare A and B. 

Instead of leaving the buffers arranged side-by-side (as obtained from
C-x 3), the buffers are displayed vertically (on top of each other) when
using 4). However, I would expect emacs to open them side-by-side as
well .

Cheers, 

Marius

Note: this is under Xubuntu 12.04.

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'.
For information about debugging Emacs, please read the file
/usr/share/emacs/24.1.50/etc/DEBUG.


In GNU Emacs 24.1.50.1 (x86_64-pc-linux-gnu, GTK+ Version 3.4.2)
 of 2012-07-13 on lychee, modified by Debian
 (emacs-snapshot package, version 2:20120712-1~ppa1~precise1)
Windowing system distributor `The X.Org Foundation', version 11.0.11103000
Configured using:
 `configure '--build' 'x86_64-linux-gnu' '--host' 'x86_64-linux-gnu'
 '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib'
 '--localstatedir=/var' '--infodir=/usr/share/info'
 '--mandir=/usr/share/man' '--with-pop=yes'
 '--enable-locallisppath=/etc/emacs-snapshot:/etc/emacs:/usr/local/share/emacs/24.1.50/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.1.50/site-lisp:/usr/share/emacs/site-lisp'
 '--without-compress-info' '--with-crt-dir=/usr/lib/x86_64-linux-gnu/'
 '--with-x=yes' '--with-x-toolkit=gtk3' '--with-imagemagick=yes'
 'build_alias=x86_64-linux-gnu' 'host_alias=x86_64-linux-gnu'
 'CFLAGS=-DDEBIAN -DSITELOAD_PURESIZE_EXTRA=5000 -g -O2' 'LDFLAGS=-g
 -Wl,--as-needed -znocombreloc' 'CPPFLAGS=-D_FORTIFY_SOURCE=2''

Important settings:
  value of $LC_MONETARY: en_US.UTF-8
  value of $LC_TIME: en_US.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Org

Minor modes in effect:
  org-indent-mode: t
  TeX-PDF-mode: t
  flyspell-mode: t
  shell-dirtrack-mode: t
  yas/global-mode: t
  yas/minor-mode: t
  desktop-save-mode: t
  ido-everywhere: t
  show-paren-mode: t
  delete-selection-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  auto-fill-function: org-auto-fill-function
  transient-mark-mode: t

Recent input:
<return> C-x b l . <return> C-x k <return> C-x b c 
o m m a n C-g C-x C-f <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> o r g / c o m m 
<tab> C-s C-g C-g M-> <left> <left> <tab> <down> <down> 
<left> <left> <tab> M-x r e p o r t - e m <tab> <r
eturn>

Recent messages:
Desktop: 7 buffers restored.
[yas] Loading snippets for emacs-lisp-mode, just in time: (yas/load-directory-1 /home/mhofert/.emacs.d/plugins/yasnippet/snippets/emacs-lisp-mode (quote emacs-lisp-mode) (quote (text-mode)))!
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bug#11960: Defective layout change on M-x ediff-buffers

[martin rudalics]

 > 1) start emacs via emacs -Q
 > 2) open a buffer A
 > 3) use C-x 3 to open another buffer (buffer B) next to A (side-by-side)
 > 4) use M-x ediff-buffers to compare A and B.
 >
 > Instead of leaving the buffers arranged side-by-side (as obtained from
 > C-x 3), the buffers are displayed vertically (on top of each other) when
 > using 4). However, I would expect emacs to open them side-by-side as
 > well .

Your expectation sounds intuitive.  But the behavior of ediff is
governed by the value of `ediff-split-window-function' and it would be
wrong to override that.  Moreover, at the time ediff applies that
function, the original frame layout has been already destroyed.

So you can either try to use something like the sloppy

(add-hook 'ediff-before-setup-hook 'my-check-configuration)

(defun my-check-configuration ()
   (setq ediff-split-window-function
	(if (window-combination-p (frame-root-window))
	    'split-window-below
	  'split-window-right)))

or permanently set `ediff-split-window-function' to `split-window-right'.

martin

bug#11960: Defective layout change on M-x ediff-buffers

[Lars Ingebrigtsen]

martin rudalics <rudalics@gmx.at> writes:

>> 1) start emacs via emacs -Q
>> 2) open a buffer A
>> 3) use C-x 3 to open another buffer (buffer B) next to A (side-by-side)
>> 4) use M-x ediff-buffers to compare A and B.
>>
>> Instead of leaving the buffers arranged side-by-side (as obtained from
>> C-x 3), the buffers are displayed vertically (on top of each other) when
>> using 4). However, I would expect emacs to open them side-by-side as
>> well .
>
> Your expectation sounds intuitive.  But the behavior of ediff is
> governed by the value of `ediff-split-window-function' and it would be
> wrong to override that.  Moreover, at the time ediff applies that
> function, the original frame layout has been already destroyed.
>
> So you can either try to use something like the sloppy
>
> (add-hook 'ediff-before-setup-hook 'my-check-configuration)
>
> (defun my-check-configuration ()
>   (setq ediff-split-window-function
> 	(if (window-combination-p (frame-root-window))
> 	    'split-window-below
> 	  'split-window-right)))
>
> or permanently set `ediff-split-window-function' to `split-window-right'.

So I guess there's nothing to fix here, and I'm closing this bug report.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no