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

1 files changed, 23 insertions, 22 deletions

diff --git a/lisp/vc-hooks.el b/lisp/vc-hooks.el
index 8d7c1acdf69..dd19ac4a0d9 100644
--- 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'.