space-stripping in _mi_prefix_search: BUG#5284

myisam/mi_search.c

@@ -451,9 +451,8 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
 	  /* We have to compare k and vseg as if they where space extended */
 	  for (end=vseg + (len-cmplen) ;
 	       vseg < end && *vseg == (uchar) ' ';
-	       vseg++) ;
-	  if (vseg == end)
-	    goto cmp_rest;		/* should never happen */
+	       vseg++, matched++) ;
+	  DBUG_ASSERT(vseg < end);
 
 	  if (*vseg > (uchar) ' ')
 	  {

mysql-test/r/myisam.result

@@ -428,6 +428,22 @@ select * from t1 where a='807780' and b='477' and c='165';
 a	b	c
 807780	477	165
 drop table t1;
+DROP TABLE IF EXISTS t1;
+Warnings:
+Note	1051	Unknown table 't1'
+CREATE TABLE t1 (a varchar(150) NOT NULL, KEY (a));
+INSERT t1 VALUES ("can \tcan");
+INSERT t1 VALUES ("can   can");
+INSERT t1 VALUES ("can");
+SELECT * FROM t1;
+a
+can 	can
+can
+can   can
+CHECK TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+DROP TABLE t1;
 create table t1 (a blob);
 insert into t1 values('a '),('a');
 select concat(a,'.') from t1 where a='a';

mysql-test/t/myisam.test

@@ -422,6 +422,18 @@ insert into t1 values('807780', '472', '162');
 select * from t1 where a='807780' and b='477' and c='165';
 drop table t1;
 
+#
+# space-stripping in _mi_prefix_search: BUG#5284
+#
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (a varchar(150) NOT NULL, KEY (a)); 
+INSERT t1 VALUES ("can \tcan"); 
+INSERT t1 VALUES ("can   can"); 
+INSERT t1 VALUES ("can"); 
+SELECT * FROM t1;
+CHECK TABLE t1;
+DROP TABLE t1;
+
 #
 # Verify blob handling
 #