bug #1172 - crash on force index() and SEL_ARG::MAYBE_KEY

mysql-test/r/range.result

@@ -260,3 +260,16 @@ explain select count(*) from t1 where x in (1,2);
 table	type	possible_keys	key	key_len	ref	rows	Extra
 t1	range	x	x	5	NULL	2	Using where; Using index
 drop table t1;
+CREATE TABLE t1 (key1 int(11) NOT NULL default '0', KEY i1 (key1), KEY i2 (key1));
+INSERT INTO t1 VALUES (0),(0),(1),(1);
+CREATE TABLE t2 (keya int(11) NOT NULL default '0', KEY j1 (keya));
+INSERT INTO t2 VALUES (0),(0),(1),(1),(2),(2);
+explain select * from t1, t2 where (t1.key1 <t2.keya + 1) and t2.keya=3;
+table	type	possible_keys	key	key_len	ref	rows	Extra
+t2	ref	j1	j1	4	const	1	Using where; Using index
+t1	ALL	i1,i2	NULL	NULL	NULL	4	Range checked for each record (index map: 3)
+explain select * from t1 force index(i2), t2 where (t1.key1 <t2.keya + 1) and t2.keya=3;
+table	type	possible_keys	key	key_len	ref	rows	Extra
+t2	ref	j1	j1	4	const	1	Using where; Using index
+t1	ALL	i2	NULL	NULL	NULL	4	Range checked for each record (index map: 2)
+DROP TABLE t1,t2;

mysql-test/t/range.test

@@ -203,3 +203,14 @@ explain select count(*) from t1 where x in (1);
 explain select count(*) from t1 where x in (1,2);
 drop table t1;
 
+#
+# bug #1172
+#
+CREATE TABLE t1 (key1 int(11) NOT NULL default '0', KEY i1 (key1), KEY i2 (key1));
+INSERT INTO t1 VALUES (0),(0),(1),(1);
+CREATE TABLE t2 (keya int(11) NOT NULL default '0', KEY j1 (keya));
+INSERT INTO t2 VALUES (0),(0),(1),(1),(2),(2);
+explain select * from t1, t2 where (t1.key1 <t2.keya + 1) and t2.keya=3;
+explain select * from t1 force index(i2), t2 where (t1.key1 <t2.keya + 1) and t2.keya=3;
+DROP TABLE t1,t2;
+

sql/opt_range.cc

@@ -716,7 +716,7 @@ int SQL_SELECT::test_quick_select(key_map keys_to_use, table_map prev_tables,
 						      param.range_count,
 						      found_records)+
 				(double) found_records / TIME_FOR_COMPARE);
-	    if (read_time > found_read_time)
+	    if (read_time > found_read_time && found_records != HA_POS_ERROR)
 	    {
 	      read_time=found_read_time;
 	      records=found_records;