vc tries to make backups on non writable directories

[bernat]

Symptoms:

Hello !

When editing a file under version control on a non writable
directorty, vc tries to make a backup of it. When the file is not
under version control, no backup are made if the directory is not writable (and 
no error occurs).

Here is a backtrace :

Debugger entered--Lisp error: (file-error "Opening output file" "permission non 
accord\xf69\ e" "/home/bernat/=these/articles/dea-english.tex.~1.12.~")
  copy-file("/home/bernat/=these/articles/dea-english.tex" 
"/home/bernat/=these/articles/dea-english.tex.~1.12.~" nil keep-date)
  vc-make-version-backup("/home/bernat/=these/articles/dea-english.tex")
  vc-before-save()
  basic-save-buffer()
  save-buffer(1)
  call-interactively(save-buffer)


In GNU Emacs 21.3.50.1 (i386-pc-linux-gnu, GTK+ Version 2.4.14, multi-tty)
 of 2005-01-30 on neo, modified by Debian
Distributor `The XFree86 Project, Inc', version 11.0.40300001
configured using `configure '--build' 'i386-linux' '--host' 'i386-linux' 
'--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' 
'--localstatedir=/var' '--infodir=/usr/share/info' '--mandir=/usr/share/man' 
'--with-pop=yes' '--with-gif' '--with-x=yes' '--with-x-toolkit=gtk' 
'CFLAGS=-DDEBIAN -g -O2' 'build_alias=i386-linux' 'host_alias=i386-linux''

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: address@hidden
  locale-coding-system: iso-latin-9
  default-enable-multibyte-characters: t

Major mode: LaTeX

Minor modes in effect:
  global-pabbrev-mode: t
  pabbrev-mode: t
  show-paren-mode: t
  encoded-kbd-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<backspace> <backspace> <tab> t h e <tab> . t e x <return> 
<return> <backspace> C-x C-s <switch-frame> <switch-frame> 
<return> C-x C-s <backspace> C-x C-s C-x v v C-g C-g 
C-x o C-x 1 C-x b <return> C-x k <return> C-x k <return> 
C-x C-f <up> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <tab> <tab> d e 
a <tab> t e <tab> <return> <return> C-x C-s q C-_ C-_ 
C-_ M-x b u g SPC <backspace> <backspace> <backspace> 
r e p o <tab> r t SPC e n <tab> <backspace> m <tab> 
b u g <return>

Recent messages:
Mark set
Press C-c C-c when you are done editing.
Enter a change comment.  Type C-c C-c when done
Quit [2 times]
Making completion list...
Entering debugger...
Back to top level.
Undo! [3 times]
Making completion list...
Loading emacsbug...done