bug#15746: 24.3; [PATCH] bookmark should confirm when overwrite

[Leo Liu]

Occationally I have overwritten bookmarks with regrets. So maybe
something along the following lines is needed.

=== modified file 'lisp/bookmark.el'
--- lisp/bookmark.el    2013-09-11 03:31:56 +0000
+++ lisp/bookmark.el    2013-10-29 03:27:15 +0000
@@ -811,6 +811,12 @@
                      bookmark-minibuffer-read-name-map
                      nil nil defaults))))
            (and (string-equal str "") (setq str default))
+           (when (and (not no-overwrite)
+                      (bookmark-get-bookmark str)
+                      (called-interactively-p 'interactive)
+                      (not (yes-or-no-p
+                            (format "Bookmark `%s' exists; overwrite? " str))))
+             (user-error "Aborted"))
            (bookmark-store str (cdr record) no-overwrite)
 
            ;; Ask for an annotation buffer for this bookmark