(font-lock-change-mode): Avoid changing buffer state in any way.

diff --git a/lisp/font-core.el b/lisp/font-core.el
index b26a86de2dcf79eea300be3d46dc5adea3497142..e394be7dba2ce439de6f4a4f0c7084cacdda7965 100644 (file)
--- a/lisp/font-core.el
+++ b/lisp/font-core.el
@@ -218,11 +218,20 @@ your own function which is called when `font-lock-mode' is toggled via
 ;; Get rid of fontification for the old major mode.
 ;; We do this when changing major modes.
 (defun font-lock-change-mode ()
-  (let ((inhibit-read-only t))
+  (let ((inhibit-read-only t)
+       (inhibit-point-motion-hooks t)
+       (inhibit-modification-hooks t)
+       (deactivate-mark nil)
+       (buffer-file-name nil)
+       (buffer-file-truename nil)
+       (buffer-undo-list t)
+       (modified (buffer-modified-p)))
     (save-restriction
       (widen)
       (remove-list-of-text-properties
-       (point-min) (point-max) '(font-lock-face))))
+       (point-min) (point-max) '(font-lock-face)))
+    (unless modified
+      (restore-buffer-modified-p nil)))
   (when font-lock-defaults
     (font-lock-unfontify-buffer)))