* lisp/simple.el (kill-new): Use equal-including-properties for

comparison.
(kill-do-not-save-duplicates): Doc fix.

2 files changed, 14 insertions, 4 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index bb03ba0b436..4f883b1cf94 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2012-03-12  Leo Liu  <sdl.web@gmail.com>
+
+        * simple.el (kill-new): Use equal-including-properties for
+        comparison.
+        (kill-do-not-save-duplicates): Doc fix.
+
 2012-03-12  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * dabbrev.el: Fix cycle completion (bug#10963).
diff --git a/lisp/simple.el b/lisp/simple.el
index f42ea3e7a50..936037f5caa 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3069,7 +3069,8 @@ before the Emacs kill and one can still paste it using \\[yank] \\[yank-pop]."
   :version "23.2")
 
 (defcustom kill-do-not-save-duplicates nil
-  "Do not add a new string to `kill-ring' when it is the same as the last one."
+  "Do not add a new string to `kill-ring' if it duplicates the last one.
+The comparison is done using `equal-including-properties'."
   :type 'boolean
   :group 'killing
   :version "23.2")
@@ -3097,7 +3098,10 @@ argument should still be a \"useful\" string for such uses."
         (signal 'args-out-of-range
                 (list string "yank-handler specified for empty string"))))
   (unless (and kill-do-not-save-duplicates
-               (equal string (car kill-ring)))
+               ;; Due to text properties such as 'yank-handler that
+               ;; can alter the contents to yank, comparison using
+               ;; `equal' is unsafe.
+               (equal-including-properties string (car kill-ring)))
     (if (fboundp 'menu-bar-update-yank-menu)
         (menu-bar-update-yank-menu string (and replace (car kill-ring)))))
   (when save-interprogram-paste-before-kill
@@ -3108,10 +3112,10 @@ argument should still be a \"useful\" string for such uses."
                        (nreverse interprogram-paste)
                      (list interprogram-paste)))
           (unless (and kill-do-not-save-duplicates
-                       (equal s (car kill-ring)))
+                       (equal-including-properties s (car kill-ring)))
             (push s kill-ring))))))
   (unless (and kill-do-not-save-duplicates
-               (equal string (car kill-ring)))
+               (equal-including-properties string (car kill-ring)))
     (if (and replace kill-ring)
         (setcar kill-ring string)
       (push string kill-ring)