Wrong result with GROUP BY + multipart key + IS (NOT) NULL + InnoDB + 1-row table + index_condition_pushdown

The following query:

SELECT a FROM t1 WHERE c IS NULL AND d IS NOT NULL GROUP BY 1;

returns a row evcen though no row matches the WHERE predicate.

Repeatable in maria-5.3. Not repeatable in maria-5.2,mysql-5.5

offending explain from maria 5.3:

| 1 | SIMPLE | t1 | index | c | PRIMARY | 4 | NULL | 1 | Using where |

correct explain from maria 5.2, mysql 5.5:

| 1 | SIMPLE | t1 | ref | c | c | 4 | const | 1 | Using where; Using filesort |

test case:

DROP TABLE t1;
CREATE TABLE t1 (
 a int NOT NULL,
 b int,
 c varchar(1),
 d varchar(1),
 PRIMARY KEY (a),
 KEY c (c,b)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES (10,8,'g','g');
SET SESSION optimizer_switch='index_condition_pushdown=ON'; # was missing previously from test case
SELECT a FROM t1 WHERE c IS NULL AND d IS NOT NULL GROUP BY 1;

bzr version-info:

revision-id: <email address hidden>
date: 2011-10-22 00:14:27 -0700
build-date: 2011-10-22 14:36:32 +0300
revno: 3246
branch-nick: maria-5.3