bug#4891: 23.1; shell-command overwrites whole buffer

bug#4891: 23.1; shell-command overwrites whole buffer

[Adam Spiers]

Starting emacs 23.1.1 with the '-q' argument and typing:

  M-: (shell-command "date" (get-buffer "*scratch*"))

results in the prior contents of the *scratch* buffer being
overwritten.  This seems to contradict the last sentence in the
following paragraph of the docstring for shell-command:

    The optional second argument output-buffer, if non-nil, says to
    put the output in some other buffer.  If output-buffer is a buffer
    or buffer name, put the output there.  If output-buffer is not a
    buffer and not nil, insert output in current buffer.  (This cannot
    be done asynchronously.)  In either case, the output is inserted
    after point (leaving mark after it).

In GNU Emacs 23.1.1 (i386-redhat-linux-gnu, GTK+ Version 2.16.6)
 of 2009-09-29 on x86-7.fedora.phx.redhat.com
Windowing system distributor `The X.Org Foundation', version 11.0.10603901
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-bu
 ffer-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_GB.utf8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  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
  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:
M-: ( s h e l l - c o m m a n d SPC " d a t e " S-SPC 
( g e t - b u f f e r SPC " * s c r a t c h * " ) ) 
<return> C-x b <return> M-x r e p o r <tab> 
<return>

Recent messages:
Loading /usr/share/emacs/site-lisp/site-start.d/muse-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/php-mode-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/po-mode-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/rpm-spec-mode-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/rpmdev-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/ruby-mode-init.el (source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.
Mon Nov  9 10:38:11 GMT 2009
0 (#o0, #x0)
Making completion list...

bug#4891: 23.1; shell-command overwrites whole buffer

[Juri Linkov]

> Starting emacs 23.1.1 with the '-q' argument and typing:
>
>   M-: (shell-command "date" (get-buffer "*scratch*"))
>
> results in the prior contents of the *scratch* buffer being
> overwritten.  This seems to contradict the last sentence in the
> following paragraph of the docstring for shell-command:
>
>     The optional second argument output-buffer, if non-nil, says to
>     put the output in some other buffer.  If output-buffer is a buffer
>     or buffer name, put the output there.  If output-buffer is not a
>     buffer and not nil, insert output in current buffer.  (This cannot
>     be done asynchronously.)  In either case, the output is inserted
>     after point (leaving mark after it).

Is the following description more precise?

    The optional second argument OUTPUT-BUFFER, if non-nil,
    says to put the output in some other buffer.
    If OUTPUT-BUFFER is a buffer or buffer name, put the output there
      replacing the old contents of that buffer.
    If OUTPUT-BUFFER is not a buffer and not nil,
      insert output in current buffer.  (This cannot be done
      asynchronously.)  In the latter case, the output is inserted
      after point (leaving mark after it).

-- 
Juri Linkov
http://www.jurta.org/emacs/

bug#4891: 23.1; shell-command overwrites whole buffer

[Adam Spiers]

On Wed, Nov 11, 2009 at 12:47:21PM +0200, Juri Linkov wrote:
> > Starting emacs 23.1.1 with the '-q' argument and typing:
> >
> >   M-: (shell-command "date" (get-buffer "*scratch*"))
> >
> > results in the prior contents of the *scratch* buffer being
> > overwritten.  This seems to contradict the last sentence in the
> > following paragraph of the docstring for shell-command:
> >
> >     The optional second argument output-buffer, if non-nil, says to
> >     put the output in some other buffer.  If output-buffer is a buffer
> >     or buffer name, put the output there.  If output-buffer is not a
> >     buffer and not nil, insert output in current buffer.  (This cannot
> >     be done asynchronously.)  In either case, the output is inserted
> >     after point (leaving mark after it).
> 
> Is the following description more precise?
> 
>     The optional second argument OUTPUT-BUFFER, if non-nil,
>     says to put the output in some other buffer.
>     If OUTPUT-BUFFER is a buffer or buffer name, put the output there
>       replacing the old contents of that buffer.
>     If OUTPUT-BUFFER is not a buffer and not nil,
>       insert output in current buffer.  (This cannot be done
>       asynchronously.)  In the latter case, the output is inserted
>       after point (leaving mark after it).

Thanks for the quick reply!  Yes, that does make more sense now - but
what if I want to asynchronously insert output into an existing
buffer?  I think it would be more useful if the code was changed to
match the docstring, rather than the other way around :-)

Regards,
Adam

bug#4891: 23.1; shell-command overwrites whole buffer

[Stefan Monnier]

> Thanks for the quick reply!  Yes, that does make more sense now - but
> what if I want to asynchronously insert output into an existing
> buffer?

Then switch to that buffer before starting the command and pass t as the
OUTPUT-BUFFER.


        Stefan

bug#4891: 23.1; shell-command overwrites whole buffer

[Kevin Rodgers]

Stefan Monnier wrote:
>> Thanks for the quick reply!  Yes, that does make more sense now - but
>> what if I want to asynchronously insert output into an existing
>> buffer?
> 
> Then switch to that buffer before starting the command and pass t as the
> OUTPUT-BUFFER.

But why is the distinction between append and replace conflated with the
OUTPUT-BUFFER argument in the first place?

-- 
Kevin Rodgers
Denver, Colorado, USA

bug#4891: 23.1; shell-command overwrites whole buffer

[Adam Spiers]

On Wed, Nov 11, 2009 at 11:23:44PM -0500, Stefan Monnier wrote:
> > Thanks for the quick reply!  Yes, that does make more sense now - but
> > what if I want to asynchronously insert output into an existing
> > buffer?
> 
> Then switch to that buffer before starting the command and pass t as the
> OUTPUT-BUFFER.

That's exactly what I tried yesterday - but that's synchronous ...

bug#4891: marked as done (23.1; shell-command overwrites whole buffer)

[Emacs bug Tracking System]

[-- Attachment #1: Type: text/plain, Size: 876 bytes --]

Your message dated Sat, 14 Nov 2009 11:09:30 -0500
with message-id <871vk1hyv9.fsf@stupidchicken.com>
and subject line Re: 23.1; shell-command overwrites whole buffer
has caused the Emacs bug report #4891,
regarding 23.1; shell-command overwrites whole buffer
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
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-- 
4891: http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=4891
Emacs Bug Tracking System
Contact owner@emacsbugs.donarmstrong.com with problems

[-- Attachment #2: Type: message/rfc822, Size: 5159 bytes --]

From: Adam Spiers <bug-gnu-emacs@adamspiers.org>
To: bug-gnu-emacs@gnu.org
Subject: 23.1; shell-command overwrites whole buffer
Date: Mon,  9 Nov 2009 11:14:14 +0000 (UTC)
Message-ID: <20091109111414.B55872414F@arctic.adamspiers.org>

Starting emacs 23.1.1 with the '-q' argument and typing:

  M-: (shell-command "date" (get-buffer "*scratch*"))

results in the prior contents of the *scratch* buffer being
overwritten.  This seems to contradict the last sentence in the
following paragraph of the docstring for shell-command:

    The optional second argument output-buffer, if non-nil, says to
    put the output in some other buffer.  If output-buffer is a buffer
    or buffer name, put the output there.  If output-buffer is not a
    buffer and not nil, insert output in current buffer.  (This cannot
    be done asynchronously.)  In either case, the output is inserted
    after point (leaving mark after it).

In GNU Emacs 23.1.1 (i386-redhat-linux-gnu, GTK+ Version 2.16.6)
 of 2009-09-29 on x86-7.fedora.phx.redhat.com
Windowing system distributor `The X.Org Foundation', version 11.0.10603901
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-bu
 ffer-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_GB.utf8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  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
  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:
M-: ( s h e l l - c o m m a n d SPC " d a t e " S-SPC 
( g e t - b u f f e r SPC " * s c r a t c h * " ) ) 
<return> C-x b <return> M-x r e p o r <tab> 
<return>

Recent messages:
Loading /usr/share/emacs/site-lisp/site-start.d/muse-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/php-mode-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/po-mode-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/rpm-spec-mode-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/rpmdev-init.el (source)...done
Loading /usr/share/emacs/site-lisp/site-start.d/ruby-mode-init.el (source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.
Mon Nov  9 10:38:11 GMT 2009
0 (#o0, #x0)
Making completion list...



[-- Attachment #3: Type: message/rfc822, Size: 2352 bytes --]

From: Chong Yidong <cyd@stupidchicken.com>
To: Adam Spiers <bug-gnu-emacs@adamspiers.org>
Cc: 4891-done@emacsbugs.donarmstrong.com
Subject: Re: 23.1; shell-command overwrites whole buffer
Date: Sat, 14 Nov 2009 11:09:30 -0500
Message-ID: <871vk1hyv9.fsf@stupidchicken.com>

>   M-: (shell-command "date" (get-buffer "*scratch*"))
>
> results in the prior contents of the *scratch* buffer being
> overwritten.  This seems to contradict the last sentence in the
> following paragraph of the docstring for shell-command:
>
>     The optional second argument output-buffer, if non-nil, says to
>     put the output in some other buffer.  If output-buffer is a buffer
>     or buffer name, put the output there.  If output-buffer is not a
>     buffer and not nil, insert output in current buffer.  (This cannot
>     be done asynchronously.)  In either case, the output is inserted
>     after point (leaving mark after it).

Thanks for the bug report.  This is really a documentation bug, because
shell-command has always erased the buffer since the first version of
Emacs, and other code depends on this behavior.  I've amended the
docstring to mention that the buffer is erased.