GNU bug report logs - #8927
24.0.50; Flaw in C-x v u

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 8927 in the body.
You can then email your comments to 8927 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Richard Stallman <rms <at> gnu.org>
To: bug-gnu-emacs <at> gnu.org
Subject: 24.0.50; Flaw in C-x v u
Date: Fri, 24 Jun 2011 05:37:28 -0400

I did C-x v = to see the changes in a file, then reverted the file
with C-x v u so I could install and commit those changes one by one.

Unfortunately, C-x v u deleted the *vc-diff* buffer and made this fail.

C-x v u should not delete the *vc-diff* buffer.



In GNU Emacs 24.0.50.1 (mips64el-unknown-linux-gnu, GTK+ Version 2.12.12)
 of 2011-06-10 on theobromine2
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: Mail

Minor modes in effect:
  diff-auto-refine-mode: t
  shell-dirtrack-mode: t
  gpm-mouse-mode: t
  display-battery-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t
  abbrev-mode: t

Recent input:
SPC v SPC - SPC DEL DEL = SPC t o SPC s e e SPC t h 
e SPC c h a n g e s SPC i n SPC a SPC f i l e , SPC 
t h e n SPC r e v e r t e d RET t h e SPC f i l e SPC 
w i t h SPC C - x SPC v SPC u SPC s o SPC I SPC c o 
u l d SPC i n s t a l l SPC a m d SPC DEL DEL DEL n 
d SPC c o m m i t SPC t h o s e SPC c h a n g e s RET 
o n e SPC b y SPC o n e . ESC q RET RET U n f o r t 
u n a t e l y , SPC C - x SPC v SPC u SPC d e l e t 
e d SPC t h e SPC * v c - d i f f * SPC b u f f e r 
SPC a n d SPC m a d e SPC t h i s SPC f a i l . RET 
RET C - x SPC v SPC u SPC s h o u l d SPC n o t SPC 
d e l e t e SPC t h e SPC * v c - d i f f * SPC b u 
f f e r . C-a C-p C-p C-p C-p C-p C-@ C-u C-n C-n C-n 
ESC w C-x m C-g ESC x r e o o r t DEL DEL DEL DEL p 
o r t SPC e m a c s TAB RET

Recent messages:
Quit
Mark set
There are unresolved conflicts in this file
Mark set
Saving file /home/rms/emacs-bzr/trunk/lisp/ChangeLog...
Wrote /home/rms/emacs-bzr/trunk/lisp/ChangeLog
Type C-h for help.
Quit [2 times]
Auto-saving...done
Mark set
Quit

Load-path shadows:
None found.

Features:
(shadow emacsbug smerge-mode ansi-color diff expect rmailedit mh-e
mh-compat mh-acros cl mh-buffers mh-loaddefs gnus gnus-ems nnheader
gnus-util time-date wid-edit cal-move cal-menu calendar cal-loaddefs
mule-util log-edit pcvs-util add-log parse-time vc-cvs sgml-mode
ispell derived byte-opt bytecomp byte-compile cconv macroexp debug
compare-w whitespace diff-mode easy-mmode vc ediff-merg ediff-diff
ediff-wind ediff-help ediff-util ediff-mult ediff-init ediff
vc-dispatcher dired-aux vc-bzr find-func help-fns warnings ind-util
rmailout kmacro quail help-mode view dabbrev shell pcomplete grep
compile multi-isearch newcomment qp mailalias rmailmm message sendmail
format-spec mml mml-sec mm-decode mm-bodies mm-encode mailabbrev
gmm-utils mailheader mail-parse rfc2231 rmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils dired t-mouse battery paren
cus-start cus-load mailcrypt rfc822 comint regexp-opt ring easymenu
mailcrypt-init tooltip ediff-hook vc-hooks lisp-float-type mwheel
x-win x-dnd tool-bar dnd fontset image fringe lisp-mode register page
menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core frame cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese hebrew greek
romanian slovak czech european ethiopic indian cyrillic chinese
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer
loaddefs button faces cus-face files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process dbusbind
dynamic-setting system-font-setting font-render-setting move-toolbar
gtk x-toolkit x multi-tty emacs)


-- 
Dr Richard Stallman
President, Free Software Foundation
51 Franklin St
Boston MA 02110
USA
www.fsf.org, www.gnu.org
Skype: No way! That's nonfree (freedom-denying) software.
  Use free telephony http://directory.fsf.org/category/tel/

Message #8 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: rms <at> gnu.org
Cc: 8927 <at> debbugs.gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Fri, 24 Jun 2011 16:59:29 -0400

Richard Stallman wrote:

> I did C-x v = to see the changes in a file, then reverted the file
> with C-x v u so I could install and commit those changes one by one.
>
> Unfortunately, C-x v u deleted the *vc-diff* buffer and made this fail.
>
> C-x v u should not delete the *vc-diff* buffer.


On a related note, it has always annoyed me that vc-revert
unconditionally always shows me the diff of the file in question before
letting me revert. Basically every time I use vc-revert, I have already
checked the diff beforehand, so all this does is introduce an annoying
delay when the backend is slow to produce a diff. I'm not aware of a
command-line VCS that show you the diff when you run its revert command,
so I don't see why Emacs should do so.

Anyway, that's why it kills your *vc-diff* buffer - because it assumes
it has just created it. The fix for your problem would presumably be for
vc-revert to only kill the buffer if it did not exist beforehand.

But personally I still wish it would not always insist on showing me the
diff.

Message #11 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Richard Stallman <rms <at> gnu.org>
To: Glenn Morris <rgm <at> gnu.org>
Cc: 8927 <at> debbugs.gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sat, 25 Jun 2011 17:54:58 -0400

    Anyway, that's why it kills your *vc-diff* buffer - because it assumes
    it has just created it. The fix for your problem would presumably be for
    vc-revert to only kill the buffer if it did not exist beforehand.

C-x v u should preserve the previous contents of *vc-diff*.


-- 
Dr Richard Stallman
President, Free Software Foundation
51 Franklin St
Boston MA 02110
USA
www.fsf.org, www.gnu.org
Skype: No way! That's nonfree (freedom-denying) software.
  Use free telephony http://directory.fsf.org/category/tel/

Message #14 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: rms <at> gnu.org
Cc: Glenn Morris <rgm <at> gnu.org>, 8927 <at> debbugs.gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sun, 26 Jun 2011 00:08:22 -0400

Richard Stallman <rms <at> gnu.org> writes:

>     Anyway, that's why it kills your *vc-diff* buffer - because it assumes
>     it has just created it. The fix for your problem would presumably be for
>     vc-revert to only kill the buffer if it did not exist beforehand.
>
> C-x v u should preserve the previous contents of *vc-diff*.

I've checked in a fix to avoid clobbering an existing vc-diff buffer
when vc-revert shows a diff temporarily.

I agree with Glenn, though, that showing a vc-diff buffer for this
operation is not a good idea.  Apart from the problems he mentioned, the
diff is not useful anyway, since there is no way to scroll the window
during the yes-nor-no prompt.  I added a new option vc-revert-show-diff
to control whether vc-revert should show a diff, and made it default to
nil.

Message #19 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Dan Nicolaescu <dann <at> gnu.org>
To: Chong Yidong <cyd <at> stupidchicken.com>
Cc: 8927 <at> debbugs.gnu.org, rms <at> gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sun, 26 Jun 2011 01:38:55 -0400

Chong Yidong <cyd <at> stupidchicken.com> writes:

> Richard Stallman <rms <at> gnu.org> writes:
>
>>     Anyway, that's why it kills your *vc-diff* buffer - because it assumes
>>     it has just created it. The fix for your problem would presumably be for
>>     vc-revert to only kill the buffer if it did not exist beforehand.
>>
>> C-x v u should preserve the previous contents of *vc-diff*.
>
> I've checked in a fix to avoid clobbering an existing vc-diff buffer
> when vc-revert shows a diff temporarily.
>
> I agree with Glenn, though, that showing a vc-diff buffer for this
> operation is not a good idea.  Apart from the problems he mentioned, the
> diff is not useful anyway, since there is no way to scroll the window
> during the yes-nor-no prompt.  I added a new option vc-revert-show-diff
> to control whether vc-revert should show a diff, and made it default to
> nil.

I strongly disagree with this change of a long standing behavior.
Showing the diff is an good visual aid in checking that the user indeed
intends to revert that file.  It's not that hard to type C-x v u in the
wrong window if one has many windows opened, and the files have similar
names.  
C-x v u is destructive, it's easy to lose data, so it seems that it
would be much better to err on the side of caution.

Can't RMS' original complaint be solved by making vc-revert use a 
*vc revert diff* buffer instead of just *vc diff*?

Message #22 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Romain Francoise <romain <at> orebokech.com>
To: Dan Nicolaescu <dann <at> gnu.org>
Cc: Chong Yidong <cyd <at> stupidchicken.com>, 8927 <at> debbugs.gnu.org, rms <at> gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sun, 26 Jun 2011 11:32:40 +0200

Dan Nicolaescu <dann <at> gnu.org> writes:

> I strongly disagree with this change of a long standing behavior.

FWIW, me too.

> Showing the diff is an good visual aid in checking that the user indeed
> intends to revert that file.  It's not that hard to type C-x v u in the
> wrong window if one has many windows opened, and the files have similar
> names.

Yes. And if you use vc-dir, you may not have the file opened at all.

Also, it's not true that the diff buffer cannot be scrolled from the
yes-or-no prompt as Chong mentioned earlier in this thread,
`scroll-other-window' and `scroll-other-window-down' work as expected.

Message #25 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Óscar Fuentes <ofv <at> wanadoo.es>
To: Chong Yidong <cyd <at> stupidchicken.com>
Cc: 8927 <at> debbugs.gnu.org, rms <at> gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sun, 26 Jun 2011 14:17:02 +0200

Chong Yidong <cyd <at> stupidchicken.com> writes:

>> C-x v u should preserve the previous contents of *vc-diff*.
>
> I've checked in a fix to avoid clobbering an existing vc-diff buffer
> when vc-revert shows a diff temporarily.
>
> I agree with Glenn, though, that showing a vc-diff buffer for this
> operation is not a good idea.  Apart from the problems he mentioned, the
> diff is not useful anyway, since there is no way to scroll the window
> during the yes-nor-no prompt.

C-M-v works fine here, and it is posible to select the other windows
with C-x o or with the mouse while the prompt is active. I'm using an
old version (2010-11-11) maybe yes-or-no changed since?

> I added a new option vc-revert-show-diff to control whether vc-revert
> should show a diff, and made it default to nil.

FWIW, I agree with Dan.

Message #28 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Glenn Morris <rgm <at> gnu.org>
Cc: 8927 <at> debbugs.gnu.org, rms <at> gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sun, 26 Jun 2011 09:10:04 -0400

> it has just created it. The fix for your problem would presumably be for
> vc-revert to only kill the buffer if it did not exist beforehand.

Right, that's the least we can do.

> But personally I still wish it would not always insist on showing me
> the diff.

I'd agree.  It should still prompt for confirmation, of course, at which
point the user can go get the diff if there's any doubt.


        Stefan

Message #31 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Richard Stallman <rms <at> gnu.org>
To: Chong Yidong <cyd <at> stupidchicken.com>
Cc: 8927 <at> debbugs.gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sun, 26 Jun 2011 12:18:09 -0400

Thanks.

-- 
Dr Richard Stallman
President, Free Software Foundation
51 Franklin St
Boston MA 02110
USA
www.fsf.org, www.gnu.org
Skype: No way! That's nonfree (freedom-denying) software.
  Use free telephony http://directory.fsf.org/category/tel/

Message #34 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: Romain Francoise <romain <at> orebokech.com>
Cc: Dan Nicolaescu <dann <at> gnu.org>, 8927 <at> debbugs.gnu.org, rms <at> gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sun, 26 Jun 2011 15:32:50 -0400

Romain Francoise <romain <at> orebokech.com> writes:

> Also, it's not true that the diff buffer cannot be scrolled from the
> yes-or-no prompt as Chong mentioned earlier in this thread,
> `scroll-other-window' and `scroll-other-window-down' work as expected.

Ah yes, forgot about that; I seldom use that functionality.

Since several are opposed, I guess it's wise to keep the old behavior.
If someone feels strongly about a change, we can discuss on emacs-devel.
Otherwise, we at least have an option to prevent the diff from being
shown.

Message #37 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Thierry Volpiatto <thierry.volpiatto <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sun, 26 Jun 2011 23:51:11 +0200

Chong Yidong <cyd <at> stupidchicken.com> writes:

> Romain Francoise <romain <at> orebokech.com> writes:
>
>> Also, it's not true that the diff buffer cannot be scrolled from the
>> yes-or-no prompt as Chong mentioned earlier in this thread,
>> `scroll-other-window' and `scroll-other-window-down' work as expected.
>
> Ah yes, forgot about that; I seldom use that functionality.

Sorry, i don't follow here, for me scrolling-other-window or whatever is
not possible from a yes-or-no-p prompt.
I can do only yes or no (as expected).
Did i miss something?

BTW I have a version ov vc-revert that:

"C-v: scroll-up, M-v: scroll-down, RET:revert, c:cancel"

If interested let me know.

-- 
A+ Thierry
Get my Gnupg key:
gpg --keyserver pgp.mit.edu --recv-keys 59F29997 

Message #40 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Óscar Fuentes <ofv <at> wanadoo.es>
To: Thierry Volpiatto <thierry.volpiatto <at> gmail.com>
Cc: 8927 <at> debbugs.gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Mon, 27 Jun 2011 00:09:00 +0200

Thierry Volpiatto <thierry.volpiatto <at> gmail.com> writes:

>>> Also, it's not true that the diff buffer cannot be scrolled from the
>>> yes-or-no prompt as Chong mentioned earlier in this thread,
>>> `scroll-other-window' and `scroll-other-window-down' work as expected.
>>
>> Ah yes, forgot about that; I seldom use that functionality.
>
> Sorry, i don't follow here, for me scrolling-other-window or whatever is
> not possible from a yes-or-no-p prompt.
> I can do only yes or no (as expected).
> Did i miss something?

scroll-other-window is bound to C-M-v, which works from the minibuffer.

[snip]

Message #43 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Richard Stallman <rms <at> gnu.org>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: rgm <at> gnu.org, 8927 <at> debbugs.gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Sun, 26 Jun 2011 19:20:43 -0400

    > it has just created it. The fix for your problem would presumably be for
    > vc-revert to only kill the buffer if it did not exist beforehand.

    Right, that's the least we can do.

If C-x v u does make and show a diff, it should do that in a
different buffer, so as to preserve the old contents of *vc-diff*.
Keeping that buffer but wiping its contents does not fix the problem.

-- 
Dr Richard Stallman
President, Free Software Foundation
51 Franklin St
Boston MA 02110
USA
www.fsf.org, www.gnu.org
Skype: No way! That's nonfree (freedom-denying) software.
  Use free telephony http://directory.fsf.org/category/tel/

Message #46 received at 8927 <at> debbugs.gnu.org (full text, mbox):

From: Thierry Volpiatto <thierry.volpiatto <at> gmail.com>
To: Óscar Fuentes <ofv <at> wanadoo.es>
Cc: 8927 <at> debbugs.gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Mon, 27 Jun 2011 06:49:21 +0200

Óscar Fuentes <ofv <at> wanadoo.es> writes:

> Thierry Volpiatto <thierry.volpiatto <at> gmail.com> writes:
>
>>>> Also, it's not true that the diff buffer cannot be scrolled from the
>>>> yes-or-no prompt as Chong mentioned earlier in this thread,
>>>> `scroll-other-window' and `scroll-other-window-down' work as expected.
>>>
>>> Ah yes, forgot about that; I seldom use that functionality.
>>
>> Sorry, i don't follow here, for me scrolling-other-window or whatever is
>> not possible from a yes-or-no-p prompt.
>> I can do only yes or no (as expected).
>> Did i miss something?
>
> scroll-other-window is bound to C-M-v, which works from the minibuffer.
I know C-M-v, but it doesn't work from the minibuffer in a y-or-n-p case.
I guess some external library break this because it is working with
emacs -Q.

-- 
A+ Thierry
Get my Gnupg key:
gpg --keyserver pgp.mit.edu --recv-keys 59F29997 

Message #49 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Thierry Volpiatto <thierry.volpiatto <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Mon, 27 Jun 2011 08:43:57 +0200

Thierry Volpiatto <thierry.volpiatto <at> gmail.com> writes:

> Óscar Fuentes <ofv <at> wanadoo.es> writes:
>
>> Thierry Volpiatto <thierry.volpiatto <at> gmail.com> writes:
>>
>>>>> Also, it's not true that the diff buffer cannot be scrolled from the
>>>>> yes-or-no prompt as Chong mentioned earlier in this thread,
>>>>> `scroll-other-window' and `scroll-other-window-down' work as expected.
>>>>
>>>> Ah yes, forgot about that; I seldom use that functionality.
>>>
>>> Sorry, i don't follow here, for me scrolling-other-window or whatever is
>>> not possible from a yes-or-no-p prompt.
>>> I can do only yes or no (as expected).
>>> Did i miss something?
>>
>> scroll-other-window is bound to C-M-v, which works from the minibuffer.
> I know C-M-v, but it doesn't work from the minibuffer in a y-or-n-p case.
> I guess some external library break this because it is working with
> emacs -Q.
This is the culprit:

(fset 'yes-or-no-p 'y-or-n-p)

that was since a long time in my .emacs.

-- 
A+ Thierry
Get my Gnupg key:
gpg --keyserver pgp.mit.edu --recv-keys 59F29997 

Message #52 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Thierry Volpiatto <thierry.volpiatto <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: Re: bug#8927: 24.0.50; Flaw in C-x v u
Date: Mon, 27 Jun 2011 08:57:55 +0200

Thierry Volpiatto <thierry.volpiatto <at> gmail.com> writes:

> Thierry Volpiatto <thierry.volpiatto <at> gmail.com> writes:
>
>> Óscar Fuentes <ofv <at> wanadoo.es> writes:
>>
>>> Thierry Volpiatto <thierry.volpiatto <at> gmail.com> writes:
>>>
>>>>>> Also, it's not true that the diff buffer cannot be scrolled from the
>>>>>> yes-or-no prompt as Chong mentioned earlier in this thread,
>>>>>> `scroll-other-window' and `scroll-other-window-down' work as expected.
>>>>>
>>>>> Ah yes, forgot about that; I seldom use that functionality.
>>>>
>>>> Sorry, i don't follow here, for me scrolling-other-window or whatever is
>>>> not possible from a yes-or-no-p prompt.
>>>> I can do only yes or no (as expected).
>>>> Did i miss something?
>>>
>>> scroll-other-window is bound to C-M-v, which works from the minibuffer.
>> I know C-M-v, but it doesn't work from the minibuffer in a y-or-n-p case.
>> I guess some external library break this because it is working with
>> emacs -Q.
> This is the culprit:
>
> (fset 'yes-or-no-p 'y-or-n-p)
>
> that was since a long time in my .emacs.
NOTE:

yes-or-no-p:
yes-or-no-p is a built-in function in `fns.c'.
It support scrolling

y-or-n-p:
y-or-n-p is a compiled Lisp function in `subr.el'.
It doesn't support scrolling.

-- 
A+ Thierry
Get my Gnupg key:
gpg --keyserver pgp.mit.edu --recv-keys 59F29997 

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.