(vc-diff): If `diff' gives empty output, return nil.

diff --git a/lisp/vc.el b/lisp/vc.el
index ff6b8e2166bc0a4cd153ade55c755f6f0bf575cc..b48e3bf07d428fbea16db76ab78777a69790102f 100644 (file)
--- a/lisp/vc.el
+++ b/lisp/vc.el
@@ -726,8 +726,14 @@ and two version designators specifying which versions to compare."
        ;; visited.  This plays hell with numerous assumptions in
        ;; the diff.el and compile.el machinery.
        (pop-to-buffer "*vc*")
-       (vc-shrink-to-fit)
-       (goto-char (point-min))
+       (pop-to-buffer "*vc*")
+       (if (= 0 (buffer-size))
+           (progn
+             (setq unchanged t)
+             (message "No changes to %s since latest version." file))
+         (vc-shrink-to-fit)
+         (goto-char (point-min)))
+
        )
       (not unchanged)
       )