bug#5773: 23.1; vc-diff save buffer when re-diffing (or save whole fileset)

[Kevin Ryde]

If you re-run M-x vc-diff from a *vc-diff* buffer, it doesn't ask you to
save the buffer being diffed the way that it does when operating from
that buffer itself

    C-x C-f /some/file/under/vc/control
    C-x v =
    C-x o
    # edit the file's buffer a bit
    C-x o           # back to the *vc-diff*
    C-x v =

    => doesn't ask about saving the edits

I wonder also if vc-diff might offer to save the whole of its "fileset",
something like below.  Not that I'm not smart enough to diff more than
one file at a time :-)

Maybe `vc-update' could share this `vc-buffer-sync-fileset' too.
I thought to use find-buffer-visiting instead of the way vc-update has
`member' in its save-some-buffers, just in case there's symlinks making
names look different.

2010-03-25  Kevin Ryde  <user42@zip.com.au>

        * vc.el (vc-buffer-sync-fileset): New function.
        (vc-diff): Use it to save all relevant file buffers no matter
        where run (not just the current buffer).

--- vc.el.~1.746.~      2009-12-17 08:25:35.000000000 +1100
+++ vc.el       2010-03-24 10:43:14.000000000 +1100
@@ -1593,9 +1593,17 @@
   (interactive (list current-prefix-arg t))
   (if historic
       (call-interactively 'vc-version-diff)
-    (when buffer-file-name (vc-buffer-sync not-urgent))
-    (vc-diff-internal t (vc-deduce-fileset t) nil nil
-                     (called-interactively-p 'interactive))))
+    (let ((fileset (vc-deduce-fileset t)))
+      (vc-buffer-sync-fileset fileset not-urgent)
+      (vc-diff-internal t fileset nil nil
+                       (called-interactively-p 'interactive)))))
+
+(defun vc-buffer-sync-fileset (fileset not-urgent)
+  (dolist (filename (cadr fileset))
+    (let ((buffer (find-buffer-visiting filename)))
+      (if buffer
+         (with-current-buffer buffer
+           (vc-buffer-sync not-urgent))))))
 
 ;;;###autoload
 (defun vc-root-diff (historic &optional not-urgent)



In GNU Emacs 23.1.1 (i486-pc-linux-gnu, GTK+ Version 2.16.5)
 of 2009-09-14 on raven, modified by Debian
configured using `configure  '--build=i486-linux-gnu' '--host=i486-linux-gnu' 
'--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' 
'--localstatedir=/var/lib' '--infodir=/usr/share/info' 
'--mandir=/usr/share/man' '--with-pop=yes' 
'--enable-locallisppath=/etc/emacs23:/etc/emacs:/usr/local/share/emacs/23.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.1/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.1/leim'
 '--with-x=yes' '--with-x-toolkit=gtk' '--with-toolkit-scroll-bars' 
'build_alias=i486-linux-gnu' 'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -g 
-O2' 'LDFLAGS=-g' 'CPPFLAGS=''

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_AU
  value of $XMODIFIERS: nil
  locale-coding-system: iso-latin-1-unix
  default-enable-multibyte-characters: t