1 files changed, 3 insertions, 1 deletions

diff --git a/lisp/vc.el b/lisp/vc.el
index b76fc7de31d..67c10a2713e 100644
--- a/lisp/vc.el
+++ b/lisp/vc.el
@@ -1487,7 +1487,9 @@ Return nil if there is no such person."
          file
          (and oldvers (concat "-r" oldvers))
          (and newvers (concat "-r" newvers))
-         diff-switches
+         (if (listp diff-switches)
+             diff-switches
+           (list diff-switches))
   ))
 
 (defun vc-check-headers ()