(vc-mode-line): Do nothing if FILE is nil.

diff --git a/lisp/vc-hooks.el b/lisp/vc-hooks.el
index 8d7c1acdf691b017aa8f0fe868bcc7c24dd8fd5d..dd19ac4a0d92cca369e123207cd81f40fb34b3c5 100644 (file)
--- a/lisp/vc-hooks.el
+++ b/lisp/vc-hooks.el
@@ -134,28 +134,29 @@ of the buffer."
 The value is set in the current buffer, which should be the buffer
 visiting FILE."
   (interactive (list buffer-file-name nil))
-  (let ((vc-type (vc-backend-deduce file)))
-    (setq vc-mode
-         (and vc-type
-              (concat " " (or label (symbol-name vc-type))
-                      (if (and vc-rcs-status (eq vc-type 'RCS))
-                          (vc-rcs-status file)))))
-    ;; Even root shouldn't modify a registered file without locking it first.
-    (and vc-type
-        (not buffer-read-only)
-        (zerop (user-uid))
-        (require 'vc)
-        (not (string-equal (user-login-name) (vc-locking-user file)))
-        (setq buffer-read-only t))
-    (and (null vc-type)
-        (file-symlink-p file)
-        (let ((link-type (vc-backend-deduce (file-symlink-p file))))
-          (if link-type
-              (message "Warning: symbolic link to %s-controlled source file"
-                       link-type))))
-    (force-mode-line-update)
-    ;;(set-buffer-modified-p (buffer-modified-p))  ;;use this if Emacs 18
-    vc-type))
+  (if file
+      (let ((vc-type (vc-backend-deduce file)))
+       (setq vc-mode
+             (and vc-type
+                  (concat " " (or label (symbol-name vc-type))
+                          (if (and vc-rcs-status (eq vc-type 'RCS))
+                              (vc-rcs-status file)))))
+       ;; Even root shouldn't modify a registered file without locking it first.
+       (and vc-type
+            (not buffer-read-only)
+            (zerop (user-uid))
+            (require 'vc)
+            (not (string-equal (user-login-name) (vc-locking-user file)))
+            (setq buffer-read-only t))
+       (and (null vc-type)
+            (file-symlink-p file)
+            (let ((link-type (vc-backend-deduce (file-symlink-p file))))
+              (if link-type
+                  (message "Warning: symbolic link to %s-controlled source file"
+                           link-type))))
+       (force-mode-line-update)
+       ;;(set-buffer-modified-p (buffer-modified-p))  ;;use this if Emacs 18
+       vc-type)))
 
 (defun vc-rcs-status (file)
   ;; Return string for placement in modeline by `vc-mode-line'.