bug#3214: 23.0.92; VC dir mode fails after commit when files are deleted

[Bob Rogers <rogers-emacs@rgrjr.dyndns.org>]

   To reproduce:

   1.  Find or create a working copy of a repository, and identify a
file that you want to remove from the repo, call it "foo.text".  (I used
SVN, but the problem doesn't seem to be backend-dependent.)  You will
need to commit in order to trigger the bug, so be sure you really don't
mind getting rid of it.

   2.  "emacs -Q" in the working copy.

   3.  "C-x C-f foo.text RET".  The deleted file must be visited in
order to trigger the bug.

   4.  Remove the file via the VC command-line tools, but don't commmit
yet.  (Don't use vc-delete-file, as that will also delete the buffer.)

   5.  "C-x v d" to get VC dir mode in the other window.  It should tag
foo.text as "removed".  (FWIW, if you do "C-x v d" first, you will see
bug #3213.)

   6.  Type "v" on the foo.text line, then "C-c C-c" in the log entry
buffer to commit the change.  You should then get a "File foo.text no
longer exists!" error.  A sample backtrace is shown below.

   The patch after the backtrace cures the symptom crudely, albeit by
papering over it, and possibly hiding other bugs.  It would be better if
vc-finish-logentry could recognize which files are being deleted, and
then have vc-resynch-buffer simply delete those buffers, but it is not
clear to me how to do that in a backend-independent way.

   Admittedly, this is a comparatively minor nuisance; the VC change is
comitted properly, and the partially-updated VC-dir buffer can be fixed
by typing "g".  (And I don't know whether this is a regression.)

					-- Bob Rogers
					   http://www.rgrjr.com/

Backtrace:
Debugger entered--Lisp error: (error "File /home/rogers/projects/test2/test/foo.text no longer exists!")
  signal(error ("File /home/rogers/projects/test2/test/foo.text no longer exists!"))
  error("File %s no longer exists!" "/home/rogers/projects/test2/test/foo.text")
  revert-buffer(t t t)
  vc-revert-buffer-internal(t t)
  vc-resynch-window("/home/rogers/projects/test2/test/foo.text" t t)
  vc-resynch-buffer("/home/rogers/projects/test2/test/foo.text" t t)
  #[(file) "=3fffc2\b	=3fffc3#=3fff87" [file vc-keep-workfiles vc-resynch-buffer t] 4]("/home/rogers/projects/test2/test/foo.text")
  mapc(#[(file) "=3fffc2\b	=3fffc3#=3fff87" [file vc-keep-workfiles vc-resynch-buffer t] 4] ("/home/rogers/projects/test2/test/foo.text"))
  vc-finish-logentry()
  call-interactively(vc-finish-logentry)
  log-edit-done()
  call-interactively(log-edit-done nil nil)
------------------------------------------------------------------------
Index: lisp/vc-dispatcher.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/vc-dispatcher.el,v
retrieving revision 1.67
diff -c -r1.67 vc-dispatcher.el
*** lisp/vc-dispatcher.el	5 Jan 2009 03:19:52 -0000	1.67
--- lisp/vc-dispatcher.el	4 May 2009 19:29:54 -0000
***************
*** 444,453 ****
      ;; and mark properly even in cases where vc-restore-buffer-context
      ;; would fail.  However, save-excursion might also get it wrong --
      ;; in this case, vc-restore-buffer-context gives it a second try.
!     (save-excursion
!       ;; t means don't call normal-mode;
!       ;; that's to preserve various minor modes.
!       (revert-buffer arg no-confirm t))
      (vc-restore-buffer-context context)))
  
  (defun vc-resynch-window (file &optional keep noquery)
--- 444,457 ----
      ;; and mark properly even in cases where vc-restore-buffer-context
      ;; would fail.  However, save-excursion might also get it wrong --
      ;; in this case, vc-restore-buffer-context gives it a second try.
!     (condition-case error
! 	(save-excursion
! 	  ;; t means don't call normal-mode;
! 	  ;; that's to preserve various minor modes.
! 	  (revert-buffer arg no-confirm t))
!       (error
!         (message "Got error %S" error)
! 	(sit-for 2)))
      (vc-restore-buffer-context context)))
  
  (defun vc-resynch-window (file &optional keep noquery)
------------------------------------------------------------------------
In GNU Emacs 23.0.92.1 (i686-pc-linux-gnu, GTK+ Version 2.12.9)
 of 2009-04-24 on rgr
Windowing system distributor `The X.Org Foundation', version 11.0.10400090
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: Debugger

Minor modes in effect:
  diff-auto-refine-mode: t
  shell-dirtrack-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-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t