"C-s M-p" brings the tip of the search ring.

* lisp/isearch.el (isearch-ring-adjust1): Start visiting previous
search strings from the index 0 (-1 + 1) instead of 1 (0 + 1).
(isearch-repeat, isearch-edit-string): Call `isearch-ring-adjust1'
for empty search string (when the last search string is reused
automatically) to adjust the isearch ring to the last element and
prepare the correct index for further M-p commands.

Fixes: debbugs:9185

2 files changed, 24 insertions, 15 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 2a33661c9c5..6716a879a76 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,12 @@
+2011-08-24  Juri Linkov  <juri@jurta.org>
+
+        * isearch.el (isearch-ring-adjust1): Start visiting previous
+        search strings from the index 0 (-1 + 1) instead of 1 (0 + 1).
+        (isearch-repeat, isearch-edit-string): Call `isearch-ring-adjust1'
+        for empty search string (when the last search string is reused
+        automatically) to adjust the isearch ring to the last element and
+        prepare the correct index for further M-p commands (bug#9185).
+
 2011-08-24  Kenichi Handa  <handa@m17n.org>
 
         * international/ucs-normalize.el: If decomposition property of
diff --git a/lisp/isearch.el b/lisp/isearch.el
index 1942641fae9..7fcc31f188f 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -1191,19 +1191,17 @@ If first char entered is \\[isearch-yank-word-or-char], then do word search inst
                   isearch-word isearch-new-word))
 
           ;; Empty isearch-string means use default.
-          (if (= 0 (length isearch-string))
-              (setq isearch-string (or (car (if isearch-regexp
-                                                regexp-search-ring
-                                              search-ring))
-                                       "")
-
-                    isearch-message
-                    (mapconcat 'isearch-text-char-description
-                               isearch-string ""))
-            ;; This used to set the last search string,
-            ;; but I think it is not right to do that here.
-            ;; Only the string actually used should be saved.
-            ))
+          (when (= 0 (length isearch-string))
+            (setq isearch-string (or (car (if isearch-regexp
+                                              regexp-search-ring
+                                            search-ring))
+                                     "")
+
+                  isearch-message
+                  (mapconcat 'isearch-text-char-description
+                             isearch-string ""))
+            ;; After taking the last element, adjust ring to previous one.
+            (isearch-ring-adjust1 nil)))
 
         ;; This used to push the state as of before this C-s, but it adds
         ;; an inconsistent state where part of variables are from the
@@ -1290,7 +1288,9 @@ Use `isearch-exit' to quit without signaling."
                   isearch-message
                   (mapconcat 'isearch-text-char-description
                              isearch-string "")
-                  isearch-case-fold-search isearch-last-case-fold-search))
+                  isearch-case-fold-search isearch-last-case-fold-search)
+            ;; After taking the last element, adjust ring to previous one.
+            (isearch-ring-adjust1 nil))
         ;; If already have what to search for, repeat it.
         (or isearch-success
             (progn
@@ -2071,7 +2071,7 @@ Isearch mode."
         ()
       (set yank-pointer-name
            (setq yank-pointer
-                 (mod (+ (or yank-pointer 0)
+                 (mod (+ (or yank-pointer (if advance 0 -1))
                          (if advance -1 1))
                       length)))
       (setq isearch-string (nth yank-pointer ring)