Make sorting not change buffer modification status always

* lisp/sort.el (sort-subr): Don't mark buffer modified if the
sorting didn't change anything (bug#4587).

diff --git a/lisp/sort.el b/lisp/sort.el
index 90eee01caf4673e9287bdd800233b5d05a2c5986..d04f075abd14cbd1811c8d808e94ee41ab9d8c33 100644 (file)
--- a/lisp/sort.el
+++ b/lisp/sort.el
@@ -29,6 +29,8 @@
 
 ;;; Code:
 
+(eval-when-compile (require 'subr-x))
+
 (defgroup sort nil
   "Commands to sort text in an Emacs buffer."
   :group 'data)
@@ -111,7 +113,8 @@ as start and end positions), and with `string<' otherwise."
                             (lambda (a b) (string< (car a) (car b)))))))
          (if reverse (setq sort-lists (nreverse sort-lists)))
          (if messages (message "Reordering buffer..."))
-         (sort-reorder-buffer sort-lists old)))
+          (with-buffer-unmodified-if-unchanged
+           (sort-reorder-buffer sort-lists old))))
       (if messages (message "Reordering buffer... Done"))))
   nil)