Merge from trunk.

1 files changed, 10 insertions, 6 deletions

diff --git a/lisp/progmodes/executable.el b/lisp/progmodes/executable.el
index d8133cb6b90..281fa3cef72 100644
--- a/lisp/progmodes/executable.el
+++ b/lisp/progmodes/executable.el
@@ -268,12 +268,16 @@ file modes."
        (save-restriction
          (widen)
          (string= "#!" (buffer-substring (point-min) (+ 2 (point-min)))))
-       (let* ((current-mode (file-modes (buffer-file-name)))
-              (add-mode (logand ?\111 (default-file-modes))))
-         (or (/= (logand ?\111 current-mode) 0)
-             (zerop add-mode)
-             (set-file-modes (buffer-file-name)
-                             (logior current-mode add-mode))))))
+       (condition-case nil
+           (let* ((current-mode (file-modes (buffer-file-name)))
+                  (add-mode (logand ?\111 (default-file-modes))))
+             (or (/= (logand ?\111 current-mode) 0)
+                 (zerop add-mode)
+                 (set-file-modes (buffer-file-name)
+                                 (logior current-mode add-mode))))
+         ;; Eg file-modes can return nil (bug#9879).  It should not,
+         ;; in this context, but we should handle it all the same.
+         (error (message "Unable to make file executable")))))
 
 (provide 'executable)