Merge from emacs-24; up to 2014-04-16T15:28:26Z!monnier@iro.umontreal.ca

[bpt/emacs.git] / lisp / simple.el

diff --git a/lisp/simple.el b/lisp/simple.el
index 0af1526..17aba8e 100644 (file)
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -2143,7 +2143,12 @@ as an argument limits undo to changes within the current region."
       ;; above when checking.
       (while (eq (car list) nil)
        (setq list (cdr list)))
-      (puthash list (if undo-in-region t pending-undo-list)
+      (puthash list
+               ;; Prevent identity mapping.  This can happen if
+               ;; consecutive nils are erroneously in undo list.
+               (if (or undo-in-region (eq list pending-undo-list))
+                   t
+                 pending-undo-list)
               undo-equiv-table))
     ;; Don't specify a position in the undo record for the undo command.
     ;; Instead, undoing this should move point to where the change is.