Merge bk-internal.mysql.com:/home/bk/mysql-5.0

into serg.mylan:/usr/home/serg/Abk/mysql-5.0

mysql-test/t/group_by.test

@@ -612,6 +612,16 @@ SELECT n+1 AS n FROM t1 GROUP BY n;
 --enable_ps_protocol
 DROP TABLE t1;
 
+#
+# BUG#12695: Item_func_isnull::update_used_tables
+# did not update const_item_cache
+#
+create table t1(f1 varchar(5) key);
+insert into t1 values (1),(2);
+select sql_buffer_result max(f1) is null from t1;
+select sql_buffer_result max(f1)+1 from t1;
+drop table t1;
+
 # End of 4.1 tests
 
 #

sql/handler.cc

@@ -570,6 +570,8 @@ int ha_prepare(THD *thd)
     {
       int err;
       statistic_increment(thd->status_var.ha_prepare_count,&LOCK_status);
+      if ((*ht)->prepare)
+      {
         if ((err= (*(*ht)->prepare)(thd, all)))
         {
           my_error(ER_ERROR_DURING_COMMIT, MYF(0), err);
@@ -578,6 +580,12 @@ int ha_prepare(THD *thd)
           break;
         }
       }
+      else
+      {
+        push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                            ER_ILLEGAL_HA, ER(ER_ILLEGAL_HA), (*ht)->name);
+      }
+    }
   }
 #endif /* USING_TRANSACTIONS */
   DBUG_RETURN(error);