Added a test case for bug #18359.

This was another manifestation of the problems fixed in the
patch for bug 16674.
Wrong calculation of length of the search prefix in the pattern
string led here to a wrong result set for a query in 4.1. 
The bug could be demonstrated for any multi-byte character set. 

mysql-test/r/ctype_utf8.result

@@ -1237,3 +1237,59 @@ a
 Käli Käli 2-4
 Käli Käli 2-4
 DROP TABLE t1;
+SET NAMES latin2;
+CREATE TABLE t1 (
+id int(11) NOT NULL default '0',
+tid int(11) NOT NULL default '0',
+val text NOT NULL,
+INDEX idx(tid, val(10))
+) ENGINE=MyISAM DEFAULT CHARSET=utf8;
+INSERT INTO t1 VALUES
+(40988,72,'VOLN ADSL'),(41009,72,'VOLN ADSL'),
+(41032,72,'VOLN ADSL'),(41038,72,'VOLN ADSL'),
+(41063,72,'VOLN ADSL'),(41537,72,'VOLN ADSL Office'),
+(42141,72,'VOLN ADSL'),(42565,72,'VOLN ADSL Combi'),
+(42749,72,'VOLN ADSL'),(44205,72,'VOLN ADSL');
+SELECT * FROM t1 WHERE tid=72 and val LIKE 'VOLNY ADSL';
+id	tid	val
+40988	72	VOLN ADSL
+41009	72	VOLN ADSL
+41032	72	VOLN ADSL
+41038	72	VOLN ADSL
+41063	72	VOLN ADSL
+42141	72	VOLN ADSL
+42749	72	VOLN ADSL
+44205	72	VOLN ADSL
+SELECT * FROM t1 WHERE tid=72 and val LIKE 'VOLN ADSL';
+id	tid	val
+40988	72	VOLN ADSL
+41009	72	VOLN ADSL
+41032	72	VOLN ADSL
+41038	72	VOLN ADSL
+41063	72	VOLN ADSL
+42141	72	VOLN ADSL
+42749	72	VOLN ADSL
+44205	72	VOLN ADSL
+SELECT * FROM t1 WHERE tid=72 and val LIKE '%VOLN ADSL';
+id	tid	val
+40988	72	VOLN ADSL
+41009	72	VOLN ADSL
+41032	72	VOLN ADSL
+41038	72	VOLN ADSL
+41063	72	VOLN ADSL
+42141	72	VOLN ADSL
+42749	72	VOLN ADSL
+44205	72	VOLN ADSL
+ALTER TABLE t1 DROP KEY idx;
+ALTER TABLE t1 ADD KEY idx (tid,val(11));
+SELECT * FROM t1 WHERE tid=72 and val LIKE 'VOLN ADSL';
+id	tid	val
+40988	72	VOLN ADSL
+41009	72	VOLN ADSL
+41032	72	VOLN ADSL
+41038	72	VOLN ADSL
+41063	72	VOLN ADSL
+42141	72	VOLN ADSL
+42749	72	VOLN ADSL
+44205	72	VOLN ADSL
+DROP TABLE t1;

mysql-test/t/ctype_utf8.test

@@ -1009,4 +1009,35 @@ ALTER TABLE t1 ADD KEY (a(10));
 SELECT * FROM t1 WHERE a LIKE 'Käli Käli 2%';
 DROP TABLE t1;
 
+#
+# Bug#18359: LIKE predicate for a 'utf8' text column with a partial index
+#            (see bug #16674 as well)
+#
+
+SET NAMES latin2;
+
+CREATE TABLE t1 (
+  id int(11) NOT NULL default '0',
+  tid int(11) NOT NULL default '0',
+  val text NOT NULL,
+  INDEX idx(tid, val(10))
+) ENGINE=MyISAM DEFAULT CHARSET=utf8;
+
+INSERT INTO t1 VALUES
+  (40988,72,'VOLN ADSL'),(41009,72,'VOLN ADSL'),
+  (41032,72,'VOLN ADSL'),(41038,72,'VOLN ADSL'),
+  (41063,72,'VOLN ADSL'),(41537,72,'VOLN ADSL Office'),
+  (42141,72,'VOLN ADSL'),(42565,72,'VOLN ADSL Combi'),
+  (42749,72,'VOLN ADSL'),(44205,72,'VOLN ADSL');
+
+SELECT * FROM t1 WHERE tid=72 and val LIKE 'VOLNY ADSL'; 
+SELECT * FROM t1 WHERE tid=72 and val LIKE 'VOLN ADSL'; 
+SELECT * FROM t1 WHERE tid=72 and val LIKE '%VOLN ADSL'; 
+
+ALTER TABLE t1 DROP KEY idx;
+ALTER TABLE t1 ADD KEY idx (tid,val(11));
+
+SELECT * FROM t1 WHERE tid=72 and val LIKE 'VOLN ADSL'; 
+
+DROP TABLE t1;
 # End of 4.1 tests