Merge with 4.1 to get new thd->mem_root handling

BitKeeper/etc/ignore:
  auto-union
client/mysqldump.c:
  Auto merged
client/mysqltest.c:
  Auto merged
innobase/include/row0mysql.h:
  Auto merged
libmysql/libmysql.c:
  Auto merged
mysql-test/r/ctype_ucs.result:
  Auto merged
mysql-test/r/fulltext.result:
  Auto merged
mysql-test/r/func_in.result:
  Auto merged
mysql-test/r/ps.result:
  Auto merged
mysql-test/r/ps_2myisam.result:
  Auto merged
mysql-test/r/ps_3innodb.result:
  Auto merged
mysql-test/r/ps_4heap.result:
  Auto merged
mysql-test/r/ps_5merge.result:
  Auto merged
mysql-test/r/ps_6bdb.result:
  Auto merged
mysql-test/r/type_float.result:
  Auto merged
mysql-test/r/user_var.result:
  Auto merged
mysql-test/t/innodb.test:
  Auto merged
mysql-test/t/user_var.test:
  Auto merged
mysql-test/t/variables.test:
  Auto merged
sql/ha_berkeley.cc:
  Auto merged
sql/ha_innodb.cc:
  Auto merged
sql/ha_innodb.h:
  Auto merged
sql/ha_ndbcluster.h:
  Auto merged
sql/item.cc:
  Auto merged
sql/item_cmpfunc.cc:
  Auto merged
sql/item_func.cc:
  Auto merged
sql/item_sum.cc:
  Auto merged
sql/item_timefunc.cc:
  Auto merged
sql/log_event.cc:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/mysqld.cc:
  Auto merged
sql/repl_failsafe.cc:
  Auto merged
sql/set_var.cc:
  Auto merged
sql/sql_acl.cc:
  Auto merged
sql/sql_db.cc:
  Auto merged
sql/sql_error.cc:
  Auto merged
sql/sql_help.cc:
  Auto merged
sql/sql_insert.cc:
  Auto merged
sql/sql_prepare.cc:
  Auto merged
sql/sql_select.h:
  Auto merged
sql/sql_yacc.yy:
  Auto merged

1 files changed, 6 insertions, 5 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index b08a6fcd2e6..905250ed96f 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -1771,12 +1771,13 @@ void Item_func_in::fix_length_and_dec()
          Conversion is possible:
          All IN arguments are constants.
       */
-      Item_arena *arena= thd->current_arena, backup;
-      if (arena->is_stmt_prepare())
-        thd->set_n_backup_item_arena(arena, &backup);
+      Item_arena *arena, backup;
+      arena= thd->change_arena_if_needed(&backup);
+
       for (arg= args+1, arg_end= args+arg_count; arg < arg_end; arg++)
       {
-        if (!my_charset_same(cmp_collation.collation,
+        if (!arg[0]->null_value &&
+            !my_charset_same(cmp_collation.collation,
                              arg[0]->collation.collation))
         {
           Item_string *conv;
@@ -1790,7 +1791,7 @@ void Item_func_in::fix_length_and_dec()
           arg[0]= conv;
         }
       }
-      if (arena->is_stmt_prepare())
+      if (arena)
         thd->restore_backup_item_arena(arena, &backup);
     }
   }