From e2f1fdab9105065bda0212bf1558eca186c2f3cb Mon Sep 17 00:00:00 2001
From: Leo Liu <sdl.web@gmail.com>
Date: Tue, 13 Mar 2012 02:21:35 +0800
Subject: [PATCH] * lisp/simple.el (kill-new): Use equal-including-properties
 for comparison. (kill-do-not-save-duplicates): Doc fix.

---
 lisp/ChangeLog |  6 ++++++
 lisp/simple.el | 12 ++++++++----
 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)
-- 
2.11.4.GIT