* lisp/isearch.el (isearch-del-char): Don't exceed the length of `isearch-string'

by the prefix arg.

Fixes: debbugs:14563

2 files changed, 12 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 974fad3e306..f21f6e4b068 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,10 @@
 2013-06-13  Juri Linkov  <juri@jurta.org>
 
+        * isearch.el (isearch-del-char): Don't exceed the length of
+        `isearch-string' by the prefix arg.  (Bug#14563)
+
+2013-06-13  Juri Linkov  <juri@jurta.org>
+
         * isearch.el (isearch-yank-word, isearch-yank-line)
         (isearch-char-by-name, isearch-quote-char)
         (isearch-printing-char, isearch-process-search-char):
diff --git a/lisp/isearch.el b/lisp/isearch.el
index 4754f86d5d7..ddb5ba9331c 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -1815,11 +1815,17 @@ If search string is empty, just beep."
   (interactive "p")
   (if (= 0 (length isearch-string))
       (ding)
-    (setq isearch-string (substring isearch-string 0 (- (or arg 1)))
+    (setq isearch-string (substring isearch-string 0
+                                    (- (min (or arg 1)
+                                            (length isearch-string))))
           isearch-message (mapconcat 'isearch-text-char-description
                                      isearch-string "")))
   ;; Use the isearch-other-end as new starting point to be able
   ;; to find the remaining part of the search string again.
+  ;; This is like what `isearch-search-and-update' does,
+  ;; but currently it doesn't support deletion of characters
+  ;; for the case where unsuccessful search may become successful
+  ;; by deletion of characters.
   (if isearch-other-end (goto-char isearch-other-end))
   (isearch-search)
   (isearch-push-state)