BUG#25729 - boolean full text search is confused by NULLs produced by

            LEFT JOIN
Fixed that in certain situations MATCH ... AGAINST returns false hits
for NULLs produced by LEFT JOIN when there is no fulltext index
available.


mysql-test/r/fulltext_left_join.result:
  A test case for BUG#25729.
mysql-test/t/fulltext_left_join.test:
  A test case for BUG#25729.
sql/item_func.cc:
  concat_ws(NULL) returns empty string instead of NULL. There is not much
  sense to calculate relevance for empty strings, thus return 0 immediately
  if we got NULL or empty string from concat_ws.
sql/item_func.h:
  Item_func_match::concat renamed to concat_ws.

1 files changed, 4 insertions, 4 deletions

diff --git a/sql/item_func.h b/sql/item_func.h
index 68591f9c6f5..3f87d210431 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -1308,12 +1308,12 @@ public:
   FT_INFO *ft_handler;
   TABLE *table;
   Item_func_match *master;   // for master-slave optimization
-  Item *concat;              // Item_func_concat_ws
-  String value;              // value of concat
+  Item *concat_ws;           // Item_func_concat_ws
+  String value;              // value of concat_ws
   String search_value;       // key_item()'s value converted to cmp_collation
 
   Item_func_match(List<Item> &a, uint b): Item_real_func(a), key(0), flags(b),
-       join_key(0), ft_handler(0), table(0), master(0), concat(0) { }
+       join_key(0), ft_handler(0), table(0), master(0), concat_ws(0) { }
   void cleanup()
   {
     DBUG_ENTER("Item_func_match");
@@ -1321,7 +1321,7 @@ public:
     if (!master && ft_handler)
       ft_handler->please->close_search(ft_handler);
     ft_handler= 0;
-    concat= 0;
+    concat_ws= 0;
     DBUG_VOID_RETURN;
   }
   enum Functype functype() const { return FT_FUNC; }