Dupport an use an observer flag in (vc-dispatcher-selection-set).

lisp/ChangeLog

@@ -2,9 +2,14 @@
 
 	* vc.el (vc-dir), vc-hooks.el: Tweak the VC directory bindings.
 	These are now documented in the manual.
-	* vc-dispatcher.el (vc-dir-update, vc-dir-parent-marked-p, 
+	* vc-dispatcher.el (vc-dir-update, vc-dir-parent-marked-p,
 	vc-dir-children-marked-p): Remove the vc-dir-insert-directories global.
 
+	* vc-dispatcher.el (vc-dispatcher-selection-set): Allow callers to
+	pass in an observer flag that says no buffer sync is required.
+	* vc.el (vc-deduce-fileset, vc-print-log, vc-version-diff): Use
+	the observer flag.
+
 2008-05-09  Michael Albinus  <michael.albinus@gmx.de>
 
 	* simple.el (start-file-process): Clarify docstring.

lisp/vc-dispatcher.el

@@ -1270,16 +1270,6 @@ U - if the cursor is on a file: unmark all the files with the same VC state
 
 (put 'vc-dir-mode 'mode-class 'special)
 
-(defun vc-buffer-sync (&optional not-urgent)
-  "Make sure the current buffer and its working file are in sync.
-NOT-URGENT means it is ok to continue if the user says not to save."
-  (when (buffer-modified-p)
-    (if (or vc-suppress-confirm
-	    (y-or-n-p (format "Buffer %s modified; save it? " (buffer-name))))
-	(save-buffer)
-      (unless not-urgent
-	(error "Aborted")))))
-
 (defun vc-dispatcher-browsing ()
   "Are we in a directory browser buffer?"
   (derived-mode-p 'vc-dir-mode))
@@ -1295,7 +1285,7 @@ NOT-URGENT means it is ok to continue if the user says not to save."
             (setq member t))))
     member))
 
-(defun vc-dispatcher-selection-set ()
+(defun vc-dispatcher-selection-set (&optional observer)
   "Deduce a set of files to which to apply an operation.  Return the fileset.
 If we're in a directory display, the fileset is the list of marked files (if
 there is one) else the file on the curreent line.  If not in a directory
@@ -1320,10 +1310,9 @@ containing that file.  Otherwise, throw an error."
     ;; We assume, in order to avoid unpleasant surprises to the user,
     ;; that a fileset is not in good shape to be handed to the user if the
     ;; buffers visiting the fileset don't match the on-disk contents.
-    ;; This is actually untrue for operations like `print-log' (or `diff'
-    ;; between two revisions), so maybe this should be moved elsewhere.
-    (save-some-buffers
-     nil (lambda () (vc-dispatcher-in-fileset-p files)))
+    (if (not observer)
+	(save-some-buffers
+	 nil (lambda () (vc-dispatcher-in-fileset-p files))))
     files))
 
 ;; arch-tag: 7d08b17f-5470-4799-914b-bfb9fcf6a246

lisp/vc.el

@@ -1002,10 +1002,10 @@ Only files already under version control are noticed."
        node (lambda (f) (when (vc-backend f) (push f flattened)))))
     (nreverse flattened)))
 
-(defun vc-deduce-fileset ()
+(defun vc-deduce-fileset (&optional observer)
   "Deduce a set of files and a backend to which to apply an operation and
 the common state of the fileset.  Return (BACKEND . FILESET)."
-  (let* ((fileset (vc-dispatcher-selection-set))
+  (let* ((fileset (vc-dispatcher-selection-set observer))
          ;; FIXME: Store the backend in a buffer-local variable.
          (backend (if (derived-mode-p 'vc-dir-mode)
                       (vc-responsible-backend default-directory)
@@ -1031,6 +1031,16 @@ the common state of the fileset.  Return (BACKEND . FILESET)."
       (unless (vc-backend buffer-file-name)
 	(error "File %s is not under version control" buffer-file-name))))))
 
+(defun vc-buffer-sync (&optional not-urgent)
+  "Make sure the current buffer and its working file are in sync.
+NOT-URGENT means it is ok to continue if the user says not to save."
+  (when (buffer-modified-p)
+    (if (or vc-suppress-confirm
+	    (y-or-n-p (format "Buffer %s modified; save it? " (buffer-name))))
+	(save-buffer)
+      (unless not-urgent
+	(error "Aborted")))))
+
 ;;; Support for the C-x v v command.
 ;; This is where all the single-file-oriented code from before the fileset
 ;; rewrite lives.
@@ -1561,7 +1571,7 @@ returns t if the buffer had changes, nil otherwise."
 (defun vc-version-diff (files rev1 rev2)
   "Report diffs between revisions of the fileset in the repository history."
   (interactive
-   (let* ((vc-fileset (vc-deduce-fileset))
+   (let* ((vc-fileset (vc-deduce-fileset t))
 	  (files (cdr vc-fileset))
           (backend (car vc-fileset))
 	  (first (car files))
@@ -2123,7 +2133,7 @@ allowed and simply skipped)."
   "List the change log of the current fileset in a window.
 If WORKING-REVISION is non-nil, leave the point at that revision."
   (interactive)
-  (let* ((vc-fileset (vc-deduce-fileset))
+  (let* ((vc-fileset (vc-deduce-fileset t))
 	 (backend (car vc-fileset))
 	 (files (cdr vc-fileset))
 	 (working-revision (or working-revision (vc-working-revision (car files)))))