Fixed LP bug #784441.

The code that added semi-join transformations missed checking
the state of the fixed flag for the items built with the
and_items function before calls of the fix_fields method.
This could lead to an abort failure when the first argument
of and_items() happened to be NULL.
 

mysql-test/r/subselect_sj.result

@@ -1266,4 +1266,27 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	C	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
 1	PRIMARY	D	ALL	NULL	NULL	NULL	NULL	3	Using where; End temporary; Using join buffer (flat, BNL join)
 drop table t1, t2;
+# 
+# BUG#784441: Abort on semijoin with a view as the inner table
+#
+CREATE TABLE t1 (a int) ;
+INSERT INTO t1 VALUES (1), (1);
+CREATE TABLE t2 (a int) ;
+INSERT INTO t2 VALUES (1), (1);
+CREATE VIEW v1 AS SELECT 1;
+EXPLAIN
+SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived3>	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
+3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
+a	a
+1	1
+1	1
+1	1
+1	1
+DROP VIEW v1;
+DROP TABLE t1,t2;
 set @@optimizer_switch=@save_optimizer_switch;

mysql-test/r/subselect_sj_jcl6.result

@@ -1274,6 +1274,29 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	C	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (incremental, BNL join)
 1	PRIMARY	D	ALL	NULL	NULL	NULL	NULL	3	Using where; End temporary; Using join buffer (incremental, BNL join)
 drop table t1, t2;
+# 
+# BUG#784441: Abort on semijoin with a view as the inner table
+#
+CREATE TABLE t1 (a int) ;
+INSERT INTO t1 VALUES (1), (1);
+CREATE TABLE t2 (a int) ;
+INSERT INTO t2 VALUES (1), (1);
+CREATE VIEW v1 AS SELECT 1;
+EXPLAIN
+SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived3>	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
+3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
+a	a
+1	1
+1	1
+1	1
+1	1
+DROP VIEW v1;
+DROP TABLE t1,t2;
 set @@optimizer_switch=@save_optimizer_switch;
 #
 # BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off

mysql-test/t/subselect_sj.test

@@ -1150,5 +1150,24 @@ select * from t1 A, t1 B
  where A.a = B.a and A.a in (select a from t2 C) and B.a in (select a from t2 D);
 drop table t1, t2;
 
+--echo # 
+--echo # BUG#784441: Abort on semijoin with a view as the inner table
+--echo #
+
+CREATE TABLE t1 (a int) ;
+INSERT INTO t1 VALUES (1), (1);
+
+CREATE TABLE t2 (a int) ;
+INSERT INTO t2 VALUES (1), (1);
+
+CREATE VIEW v1 AS SELECT 1;
+
+EXPLAIN
+SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
+SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
+
+DROP VIEW v1;
+DROP TABLE t1,t2;
+
 # The following command must be the last one the file 
 set @@optimizer_switch=@save_optimizer_switch;

sql/opt_subselect.cc

@@ -1256,7 +1256,8 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
     }
   }
   /* Fix the created equality and AND */
-  sj_nest->sj_on_expr->fix_fields(parent_join->thd, &sj_nest->sj_on_expr);
+  if (!sj_nest->sj_on_expr->fixed)
+    sj_nest->sj_on_expr->fix_fields(parent_join->thd, &sj_nest->sj_on_expr);
 
   /*
     Walk through sj nest's WHERE and ON expressions and call
@@ -1277,7 +1278,9 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
   {
     emb_tbl_nest->on_expr= and_items(emb_tbl_nest->on_expr, 
                                      sj_nest->sj_on_expr);
-    emb_tbl_nest->on_expr->fix_fields(parent_join->thd, &emb_tbl_nest->on_expr);
+    if (!emb_tbl_nest->on_expr->fixed)
+      emb_tbl_nest->on_expr->fix_fields(parent_join->thd,
+                                        &emb_tbl_nest->on_expr);
   }
   else
   {
@@ -1289,7 +1292,8 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
     */
     save_lex= thd->lex->current_select;
     thd->lex->current_select=parent_join->select_lex;
-    parent_join->conds->fix_fields(parent_join->thd, &parent_join->conds);
+    if (!parent_join->conds->fixed)
+      parent_join->conds->fix_fields(parent_join->thd, &parent_join->conds);
     thd->lex->current_select=save_lex;
     parent_join->select_lex->where= parent_join->conds;
   }

sql/sql_select.cc

@@ -831,7 +831,8 @@ inject_jtbm_conds(JOIN *join, List<TABLE_LIST> *join_list, Item **join_where)
       Item *sj_conds= hash_sj_engine->semi_join_conds;
 
       (*join_where)= and_items(*join_where, sj_conds);
-      (*join_where)->fix_fields(join->thd, join_where);
+      if (!(*join_where)->fixed)
+        (*join_where)->fix_fields(join->thd, join_where);
       //parent_join->select_lex->where= parent_join->conds;
     }