BUG#727667 Wrong result with OR + NOT NULL in maria-5.3

- put the code that sets HA_NULL_PART bit back
- Fix test_if_ref/part_of_refkey() so that 
  = NULL-ability of lookup columns does not prevent the equality 
    from being removed (we now have early/late NULLs filtering which 
    will filter out NULL values)
  = equality is not removed if it is ref_or_null access, and the value 
    of the lookup column can alternate between the lookup value and NULL.

1 files changed, 19 insertions, 7 deletions

diff --git a/mysql-test/r/null_key.result b/mysql-test/r/null_key.result
index 67725c45314..db2f662eeac 100644
--- a/mysql-test/r/null_key.result
+++ b/mysql-test/r/null_key.result
@@ -21,10 +21,10 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	a,b	a	9	NULL	3	Using where; Using index
 explain select * from t1 where (a is null or a = 7) and b=7;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref_or_null	a,b	a	9	const,const	2	Using index
+1	SIMPLE	t1	ref_or_null	a,b	a	9	const,const	2	Using where; Using index
 explain select * from t1 where (a is null or a = 7) and b=7 order by a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref_or_null	a,b	a	9	const,const	2	Using index; Using filesort
+1	SIMPLE	t1	ref_or_null	a,b	a	9	const,const	2	Using where; Using index; Using filesort
 explain select * from t1 where (a is null and b>a) or a is null and b=7 limit 2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	a,b	a	5	const	3	Using where; Using index
@@ -151,7 +151,7 @@ alter table t1 modify b int null;
 insert into t1 values (7,null), (8,null), (8,7);
 explain select * from t1 where a = 7 and (b=7 or b is null);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref_or_null	a,b	a	10	const,const	2	Using index
+1	SIMPLE	t1	ref_or_null	a,b	a	10	const,const	2	Using where; Using index
 select * from t1 where a = 7 and (b=7 or b is null);
 a	b
 7	7
@@ -166,7 +166,7 @@ a	b
 NULL	7
 explain select * from t1 where (a = 7 or a is null) and (a = 7 or a is null);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref_or_null	a	a	5	const	5	Using index
+1	SIMPLE	t1	ref_or_null	a	a	5	const	5	Using where; Using index
 select * from t1 where (a = 7 or a is null) and (a = 7 or a is null);
 a	b
 7	NULL
@@ -192,7 +192,7 @@ a	a	b
 explain select * from t2,t1 where t1.a=t2.a and (b= 7 or b is null);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
-1	SIMPLE	t1	ref_or_null	a	a	10	test.t2.a,const	4	Using index
+1	SIMPLE	t1	ref_or_null	a	a	10	test.t2.a,const	4	Using where; Using index
 select * from t2,t1 where t1.a=t2.a and (b= 7 or b is null);
 a	a	b
 7	7	7
@@ -202,7 +202,7 @@ a	a	b
 explain select * from t2,t1 where (t1.a=t2.a or t1.a is null) and b= 7;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	
-1	SIMPLE	t1	ref_or_null	a	a	10	test.t2.a,const	4	Using index
+1	SIMPLE	t1	ref_or_null	a	a	10	test.t2.a,const	4	Using where; Using index
 select * from t2,t1 where (t1.a=t2.a or t1.a is null) and b= 7;
 a	a	b
 7	7	7
@@ -226,7 +226,7 @@ delete from t1 where a=8;
 explain select * from t2,t1 where t1.a=t2.a or t1.a is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t1	ref_or_null	a	a	5	test.t2.a	4	Using index
+1	SIMPLE	t1	ref_or_null	a	a	5	test.t2.a	4	Using where; Using index
 explain select * from t2,t1 where t1.a<=>t2.a or (t1.a is null and t1.b <> 9);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	4	
@@ -447,3 +447,15 @@ a	b	a	b
 3	12	0	12
 drop table t1, t2;
 End of 5.0 tests
+#
+#  BUG#727667 Wrong result with OR + NOT NULL in maria-5.3
+# 
+CREATE TABLE t1 (
+f3 int(11),
+f10 varchar(1),
+KEY (f3)
+);
+INSERT INTO t1 VALUES ('9','k'),(NULL,'r');
+SELECT * FROM t1 WHERE (f3 = 83) OR (f10 = 'z' AND f3 IS NULL);
+f3	f10
+DROP TABLE t1;