fix of Item_ref with result_field (BUG#5104)

mysql-test/r/view.result:
  distinct in temporary table with a VIEW
mysql-test/t/view.test:
  distinct in temporary table with a VIEW
sql/item.cc:
  fix of Item_ref with result_field
sql/item.h:
  fix of Item_ref with result_field

mysql-test/r/view.result

@@ -1116,3 +1116,21 @@ c1	c2
 7	almost real Beer
 drop view v1;
 drop table t1;
+create table t1 (a int);
+insert into t1 values (1),(1),(2),(2),(3),(3);
+create view v1 as select a from t1;
+select distinct a from v1;
+a
+1
+2
+3
+select distinct a from v1 limit 2;
+a
+1
+2
+select distinct a from t1 limit 2;
+a
+1
+2
+drop view v1;
+drop table t1;

mysql-test/t/view.test

@@ -1066,3 +1066,15 @@ CREATE VIEW v1 AS SELECT  * from t1 WHERE match (c2) against ('Beer');
 select * from v1;
 drop view v1;
 drop table t1;
+
+#
+# distinct in temporary table with a VIEW
+#
+create table t1 (a int);
+insert into t1 values (1),(1),(2),(2),(3),(3);
+create view v1 as select a from t1;
+select distinct a from v1;
+select distinct a from v1 limit 2;
+select distinct a from t1 limit 2;
+drop view v1;
+drop table t1;

sql/item.cc

@@ -2156,6 +2156,14 @@ void Item_ref::print(String *str)
 }
 
 
+bool Item_ref::send(Protocol *prot, String *tmp)
+{
+  if (result_field)
+    return prot->store(result_field);
+  return (*ref)->send(prot, tmp);
+}
+
+
 void Item_ref_null_helper::print(String *str)
 {
   str->append("<ref_null_helper>(", 18);

sql/item.h

@@ -964,7 +964,7 @@ public:
   {
     return (null_value=(*ref)->get_date_result(ltime,fuzzydate));
   }
-  bool send(Protocol *prot, String *tmp){ return (*ref)->send(prot, tmp); }
+  bool send(Protocol *prot, String *tmp);
   void make_field(Send_field *field)	{ (*ref)->make_field(field); }
   bool fix_fields(THD *, struct st_table_list *, Item **);
   int save_in_field(Field *field, bool no_conversions)