bug#14268: 24.3.50; isearch-repeat-forward without isearch-forward first signals error

[Darren Hoo]

Start Emacs cleanly and doing an isearch-repeat-forward, it is
expected to show the message [No previous search string] in the
echo area, but it raises the following instead:

Debugger entered--Lisp error: (wrong-type-argument arrayp nil)
  isearch-fail-pos(t)
  isearch-message()
  isearch-update()
  isearch-repeat(forward)
  isearch-repeat-forward()
  call-interactively(isearch-repeat-forward nil nil)
  command-execute(isearch-repeat-forward)


In GNU Emacs 24.3.50.1 (x86_64-apple-darwin12.3.0, NS apple-appkit-1187.37)
 of 2013-04-25 on Darren-rMBP.local
Bzr revision: 112377 yamaoka@jpl.org-20130424220721-t957vh44sdvmxj28
Windowing system distributor `Apple', version 10.3.1187
Configured using:
 `configure --with-ns'

diff --git a/lisp/isearch.el b/lisp/isearch.el
index b36b250..b38bfc8 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -1106,8 +1106,9 @@ If MSG is non-nil, use variable
`isearch-message', otherwise `isearch-string'."
        (curr-msg (if msg isearch-message isearch-string))
        succ-msg)
     (when (or (not isearch-success) isearch-error)
-      (while (or (not (isearch--state-success (car cmds)))
-                 (isearch--state-error (car cmds)))
+      (while (and cmds
+                 (or (not (isearch--state-success (car cmds)))
+                     (isearch--state-error (car cmds))))
         (pop cmds))
       (setq succ-msg (and cmds (if msg (isearch--state-message (car cmds))
                                 (isearch--state-string (car cmds)))))