bug#6447: 23.1; revert-buffer in *vc-diff*

[Juri Linkov]

> I typed '=' in a *vc-dir* buffer to get a diff.
> It would be nice if revert-buffer in the *vc-diff* buffer re-ran the
> same diff command.

Like the command `diff' after calling `diff-mode' sets
`revert-buffer-function' to lambda with its function arguments,
`vc-diff-internal' could do the same:

=== modified file 'lisp/vc/vc.el'
--- lisp/vc/vc.el       2010-06-11 19:09:57 +0000
+++ lisp/vc/vc.el       2010-06-19 14:51:14 +0000
@@ -1547,6 +1547,9 @@ (defun vc-diff-internal (async vc-filese
           (message "%s" (cdr messages))
           nil)
       (diff-mode)
+      (set (make-local-variable 'revert-buffer-function)
+          `(lambda (ignore-auto noconfirm)
+             (vc-diff-internal ,async ',vc-fileset ,rev1 ,rev2 ,verbose)))
       ;; Make the *vc-diff* buffer read only, the diff-mode key
       ;; bindings are nicer for read only buffers. pcl-cvs does the
       ;; same thing.

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