Backport Bug#13724099

sql/sql_list.h

 #ifndef INCLUDES_MYSQL_SQL_LIST_H
 #define INCLUDES_MYSQL_SQL_LIST_H
-/*
-   Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+/* Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -165,6 +164,14 @@ protected:
 public:
   uint elements;
 
+  bool operator==(const base_list &rhs) const
+  {
+    return
+      elements == rhs.elements &&
+      first == rhs.first &&
+      last == rhs.last;
+  }
+
   inline void empty() { elements=0; first= &end_of_list; last=&first;}
   inline base_list() { empty(); }
   /**

sql/sql_select.cc

-/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
+/* Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -1676,6 +1676,8 @@ JOIN::optimize()
 */
 void JOIN::restore_tmp()
 {
+  DBUG_PRINT("info", ("restore_tmp this %p tmp_join %p", this, tmp_join));
+  DBUG_ASSERT(tmp_join != this);
   memcpy(tmp_join, this, (size_t) sizeof(JOIN));
 }
 
@@ -7090,13 +7092,18 @@ void JOIN::cleanup(bool full)
   {
     if (tmp_join)
       tmp_table_param.copy_field= 0;
-    group_fields.delete_elements();
+
     /* 
-      Ensure that the above delete_elements() would not be called
+      Ensure that the following delete_elements() would not be called
       twice for the same list.
     */
-    if (tmp_join && tmp_join != this)
-      tmp_join->group_fields= group_fields;
+    if (tmp_join && tmp_join != this &&
+        tmp_join->group_fields == this->group_fields)
+      tmp_join->group_fields.empty();
+
+    // Run Cached_item DTORs!
+    group_fields.delete_elements();
+
     /*
       We can't call delete_elements() on copy_funcs as this will cause
       problems in free_elements() as some of the elements are then deleted.