backport Serg's fix of FT interface (BUG#6523)

mysql-test/r/subselect.result:
  subqueries with full text search
mysql-test/t/subselect.test:
  subqueries with full text search
sql/ha_myisam.h:
  backport Serg's fix of FT interface
sql/handler.h:
  backport Serg's fix of FT interface
sql/opt_range.h:
  backport Serg's fix of FT interface
sql/sql_select.cc:
  comment for previous patch

mysql-test/r/subselect.result

@@ -2003,3 +2003,11 @@ a	b	(select max(b) from t2 where t1.b=t2.a)
 2	4	NULL
 2	5	NULL
 drop table t1, t2;
+create table t1 (id int);
+create table t2 (id int, body text, fulltext (body));
+insert into t1 values(1),(2),(3);
+insert into t2 values (1,'test'), (2,'mysql'), (3,'test'), (4,'test');
+select count(distinct id) from t1 where id in (select id from t2 where match(body) against ('mysql' in boolean mode));
+count(distinct id)
+1
+drop table t2,t1;

mysql-test/t/subselect.test

@@ -1299,3 +1299,13 @@ insert into t1 values (1,1),(1,2),(1,3),(2,4),(2,5);
 insert into t2 values (1,3),(2,1);
 select distinct a,b, (select max(b) from t2 where t1.b=t2.a) from t1 order by t1.b;
 drop table t1, t2;
+
+#
+# subqueries with full text search
+#
+create table t1 (id int);
+create table t2 (id int, body text, fulltext (body));
+insert into t1 values(1),(2),(3);
+insert into t2 values (1,'test'), (2,'mysql'), (3,'test'), (4,'test');
+select count(distinct id) from t1 where id in (select id from t2 where match(body) against ('mysql' in boolean mode));
+drop table t2,t1;

sql/ha_myisam.h

@@ -81,7 +81,6 @@ class ha_myisam: public handler
   int index_first(byte * buf);
   int index_last(byte * buf);
   int index_next_same(byte *buf, const byte *key, uint keylen);
-  int index_end() { ft_handler=NULL; return 0; }
   int ft_init()
   {
     if (!ft_handler)

sql/handler.h

@@ -372,6 +372,7 @@ class handler :public Sql_alloc
   virtual int read_range_next();
   int compare_key(key_range *range);
   virtual int ft_init() { return HA_ERR_WRONG_COMMAND; }
+  void ft_end() { ft_handler=NULL; }
   virtual FT_INFO *ft_init_ext(uint flags,uint inx,const byte *key,
                                uint keylen)
     { return NULL; }

sql/opt_range.h

@@ -154,7 +154,7 @@ class FT_SELECT: public QUICK_SELECT {
 public:
   FT_SELECT(THD *thd, TABLE *table, uint key):
     QUICK_SELECT (thd, table, key, 1) { init(); }
-
+  ~FT_SELECT() { file->ft_end(); }
   int init() { return error= file->ft_init(); }
   int get_next() { return error= file->ft_read(record); }
 };

sql/sql_select.cc

@@ -3834,7 +3834,7 @@ JOIN::join_free(bool full)
   DBUG_ENTER("JOIN::join_free");
 
   full= full || (!select_lex->uncacheable &&
-                 !thd->lex->describe);
+                 !thd->lex->describe); // do not cleanup too early on EXPLAIN
 
   if (table)
   {