Fixed bug #25637: LEFT JOIN with BOOLEAN FULLTEXT loses left table matches.

The bug is actually a duplicate of the bug 14708.
Down-ported the fix for 14708 from 5.0.  
Merged the test case for bug 14708 from 5.0.

mysql-test/r/fulltext_left_join.result

@@ -50,3 +50,43 @@ venue_id	venue_text	dt	name	entity_id
 1	a1	2003-05-23 19:30:00	aberdeen town hall	1
 NULL	a2	2003-05-23 19:30:00	NULL	NULL
 drop table t1,t2;
+create table t1 (id int not null primary key, d char(200) not null, e char(200));
+insert into t1 values (1, 'aword', null), (2, 'aword', 'bword'), (3, 'bword', null), (4, 'bword', 'aword'), (5, 'aword and bword', null);
+select * from t1 where match(d, e) against ('+aword +bword' in boolean mode);
+id	d	e
+2	aword	bword
+4	bword	aword
+5	aword and bword	NULL
+create table t2 (m_id int not null, f char(200), key (m_id));
+insert into t2 values (1, 'bword'), (3, 'aword'), (5, '');
+select * from t1 left join t2 on m_id = id where match(d, e, f) against ('+aword +bword' in boolean mode);
+id	d	e	m_id	f
+1	aword	NULL	1	bword
+2	aword	bword	NULL	NULL
+3	bword	NULL	3	aword
+4	bword	aword	NULL	NULL
+5	aword and bword	NULL	5	
+drop table t1,t2;
+CREATE TABLE t1 (
+id int(10) NOT NULL auto_increment,
+link int(10) default NULL,
+name mediumtext default NULL,
+PRIMARY KEY (id),
+FULLTEXT (name)
+);
+INSERT INTO t1 VALUES (1, 1, 'string');
+INSERT INTO t1 VALUES (2, 0, 'string');
+CREATE TABLE t2 (
+id int(10) NOT NULL auto_increment,
+name mediumtext default NULL,
+PRIMARY KEY (id),
+FULLTEXT (name)
+);
+INSERT INTO t2 VALUES (1, 'string');
+SELECT t1.*, MATCH(t1.name) AGAINST('string') AS relevance 
+FROM t1 LEFT JOIN t2 ON t1.link = t2.id
+WHERE MATCH(t1.name, t2.name) AGAINST('string' IN BOOLEAN MODE);
+id	link	name	relevance
+1	1	string	0
+2	0	string	0
+DROP TABLE t1,t2;

mysql-test/t/fulltext_left_join.test

@@ -45,4 +45,45 @@ select * from t1 left join t2 on (venue_id = entity_id and match(name) against('
 select * from t1 left join t2 on (venue_id = entity_id and match(name) against('aberdeen')) where dt = '2003-05-23 19:30:00';
 drop table t1,t2;
 
+#
+# BUG#14708
+# Inconsistent treatment of NULLs in LEFT JOINed FULLTEXT matching without index
+#
+
+create table t1 (id int not null primary key, d char(200) not null, e char(200));
+insert into t1 values (1, 'aword', null), (2, 'aword', 'bword'), (3, 'bword', null), (4, 'bword', 'aword'), (5, 'aword and bword', null);
+select * from t1 where match(d, e) against ('+aword +bword' in boolean mode);
+create table t2 (m_id int not null, f char(200), key (m_id));
+insert into t2 values (1, 'bword'), (3, 'aword'), (5, '');
+select * from t1 left join t2 on m_id = id where match(d, e, f) against ('+aword +bword' in boolean mode);
+drop table t1,t2;
+
+#
+# BUG#25637: LEFT JOIN with BOOLEAN FULLTEXT loses left table matches
+#            (this is actually the same bug as bug #14708)
+#
+
+CREATE TABLE t1 (
+  id int(10) NOT NULL auto_increment,
+  link int(10) default NULL,
+  name mediumtext default NULL,
+  PRIMARY KEY (id),
+  FULLTEXT (name)
+);
+INSERT INTO t1 VALUES (1, 1, 'string');
+INSERT INTO t1 VALUES (2, 0, 'string');
+CREATE TABLE t2 (
+    id int(10) NOT NULL auto_increment,
+    name mediumtext default NULL,
+    PRIMARY KEY (id),
+    FULLTEXT (name)
+);
+INSERT INTO t2 VALUES (1, 'string');
+
+SELECT t1.*, MATCH(t1.name) AGAINST('string') AS relevance 
+  FROM t1 LEFT JOIN t2 ON t1.link = t2.id
+    WHERE MATCH(t1.name, t2.name) AGAINST('string' IN BOOLEAN MODE);
+
+DROP TABLE t1,t2;
+
 # End of 4.1 tests

sql/item_func.cc

@@ -3247,7 +3247,7 @@ double Item_func_match::val()
   if (ft_handler == NULL)
     DBUG_RETURN(-1.0);
 
-  if (table->null_row) /* NULL row from an outer join */
+  if (key != NO_SUCH_KEY && table->null_row) /* NULL row from an outer join */
     return 0.0;
 
   if (join_key)