Bug#21555: incorrect behavior with INSERT ... ON DUPL KEY UPDATE and VALUES

 VALUES() was considered a constant. This caused replacing 
 (or pre-calculating) it using uninitialized values before the actual
 execution takes place.
 Mark it as a non-constant (still not dependent of tables) to prevent
 the pre-calculation.


mysql-test/r/insert_update.result:
  Bug#21555: incorrect behavior with INSERT ... ON DUPL KEY UPDATE and VALUES
   - test case.
   - EXPLAIN output changed due to VALUES() not being considered a constant 
     anymore
mysql-test/t/insert_update.test:
  Bug#21555: incorrect behavior with INSERT ... ON DUPL KEY UPDATE and VALUES
   - test case.
sql/item.h:
  Bug#21555: incorrect behavior with INSERT ... ON DUPL KEY UPDATE and VALUES
   - mark Item_insert_value as non-constant to prevent early calculation.

1 files changed, 24 insertions, 2 deletions

diff --git a/mysql-test/r/insert_update.result b/mysql-test/r/insert_update.result
index 9e674cc4aae..c41aab29853 100644
--- a/mysql-test/r/insert_update.result
+++ b/mysql-test/r/insert_update.result
@@ -63,9 +63,9 @@ Warnings:
 Note	1003	select test.t1.a AS `a`,test.t1.b AS `b`,test.t1.c AS `c`,values(test.t1.a) AS `VALUES(a)` from test.t1
 explain extended select * from t1 where values(a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	Using where
 Warnings:
-Note	1003	select test.t1.a AS `a`,test.t1.b AS `b`,test.t1.c AS `c` from test.t1
+Note	1003	select test.t1.a AS `a`,test.t1.b AS `b`,test.t1.c AS `c` from test.t1 where values(test.t1.a)
 DROP TABLE t1;
 create table t1(a int primary key, b int);
 insert into t1 values(1,1),(2,2),(3,3),(4,4),(5,5);
@@ -197,3 +197,25 @@ PRIMARY KEY  (a)
 ) ENGINE=MyISAM;
 INSERT INTO t1 ( a ) SELECT 0 ON DUPLICATE KEY UPDATE a = a + VALUES (a) ;
 DROP TABLE t1;
+CREATE TABLE t1
+(
+a   BIGINT UNSIGNED,
+b   BIGINT UNSIGNED,
+PRIMARY KEY (a)
+);
+INSERT INTO t1 VALUES (45, 1) ON DUPLICATE KEY UPDATE b =
+IF(VALUES(b) > t1.b, VALUES(b), t1.b);
+SELECT * FROM t1;
+a	b
+45	1
+INSERT INTO t1 VALUES (45, 2) ON DUPLICATE KEY UPDATE b =
+IF(VALUES(b) > t1.b, VALUES(b), t1.b);
+SELECT * FROM t1;
+a	b
+45	2
+INSERT INTO t1 VALUES (45, 1) ON DUPLICATE KEY UPDATE b = 
+IF(VALUES(b) > t1.b, VALUES(b), t1.b);
+SELECT * FROM t1;
+a	b
+45	2
+DROP TABLE t1;