fix for bug #13545: Server crash caused by select query.

sql/sql_base.cc:
  fix for bug #13545: Server crash caused by select query.
  - compare table qualifier only with tables which are not nested joins.
  - perform recursion accordingly.
  - DBUG_ASSERT(table_list->table); added before the find_field_in_table() call.

mysql-test/r/join_nested.result

@@ -1375,3 +1375,31 @@ groupid	price
 6	9900
 DROP VIEW v1,v2;
 DROP TABLE t1,t2,t3,t4;
+CREATE TABLE t1(a int);
+CREATE TABLE t2(b int);
+CREATE TABLE t3(c int, d int);
+CREATE TABLE t4(d int);
+CREATE TABLE t5(e int, f int);
+CREATE TABLE t6(f int);
+CREATE VIEW v1 AS 
+SELECT e FROM t5 JOIN t6 ON t5.e=t6.f;
+CREATE VIEW v2 AS 
+SELECT e FROM t5 NATURAL JOIN t6;
+SELECT t1.a FROM t1 JOIN t2 ON a=b JOIN t3 ON a=c JOIN t4 USING(d);
+a
+SELECT t1.x FROM t1 JOIN t2 ON a=b JOIN t3 ON a=c JOIN t4 USING(d);
+ERROR 42S22: Unknown column 't1.x' in 'field list'
+SELECT t1.a FROM t1 JOIN t2 ON a=b JOIN t3 ON a=c NATURAL JOIN t4;
+a
+SELECT t1.x FROM t1 JOIN t2 ON a=b JOIN t3 ON a=c NATURAL JOIN t4;
+ERROR 42S22: Unknown column 't1.x' in 'field list'
+SELECT v1.e FROM v1 JOIN t2 ON e=b JOIN t3 ON e=c JOIN t4 USING(d);
+e
+SELECT v1.x FROM v1 JOIN t2 ON e=b JOIN t3 ON e=c JOIN t4 USING(d);
+ERROR 42S22: Unknown column 'v1.x' in 'field list'
+SELECT v2.e FROM v2 JOIN t2 ON e=b JOIN t3 ON e=c JOIN t4 USING(d);
+e
+SELECT v2.x FROM v2 JOIN t2 ON e=b JOIN t3 ON e=c JOIN t4 USING(d);
+ERROR 42S22: Unknown column 'v2.x' in 'field list'
+DROP VIEW v1, v2;
+DROP TABLE t1, t2, t3, t4, t5, t6;

mysql-test/t/join_nested.test

@@ -801,3 +801,34 @@ SELECT * FROM
 
 DROP VIEW v1,v2;
 DROP TABLE t1,t2,t3,t4;
+
+#
+# Bug #13545: problem with NATURAL/USING joins.
+#
+
+CREATE TABLE t1(a int);
+CREATE TABLE t2(b int);
+CREATE TABLE t3(c int, d int);
+CREATE TABLE t4(d int);
+CREATE TABLE t5(e int, f int);
+CREATE TABLE t6(f int);
+CREATE VIEW v1 AS 
+  SELECT e FROM t5 JOIN t6 ON t5.e=t6.f;
+CREATE VIEW v2 AS 
+  SELECT e FROM t5 NATURAL JOIN t6;
+
+SELECT t1.a FROM t1 JOIN t2 ON a=b JOIN t3 ON a=c JOIN t4 USING(d);
+--error 1054
+SELECT t1.x FROM t1 JOIN t2 ON a=b JOIN t3 ON a=c JOIN t4 USING(d);
+SELECT t1.a FROM t1 JOIN t2 ON a=b JOIN t3 ON a=c NATURAL JOIN t4;
+--error 1054
+SELECT t1.x FROM t1 JOIN t2 ON a=b JOIN t3 ON a=c NATURAL JOIN t4;
+SELECT v1.e FROM v1 JOIN t2 ON e=b JOIN t3 ON e=c JOIN t4 USING(d);
+--error 1054
+SELECT v1.x FROM v1 JOIN t2 ON e=b JOIN t3 ON e=c JOIN t4 USING(d);
+SELECT v2.e FROM v2 JOIN t2 ON e=b JOIN t3 ON e=c JOIN t4 USING(d);
+--error 1054
+SELECT v2.x FROM v2 JOIN t2 ON e=b JOIN t3 ON e=c JOIN t4 USING(d);
+
+DROP VIEW v1, v2;
+DROP TABLE t1, t2, t3, t4, t5, t6;

sql/sql_base.cc

@@ -2988,7 +2988,7 @@ find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
     are the same as the table reference we are going to search for the field.
 
     We exclude from the test below NATURAL/USING joins and any nested join
-    that is an operand of NATURAL/USING join, because each column in such
+    because each column in such
     joins may potentially originate from a different table. However, base
     tables and views that are under some NATURAL/USING join are searched
     as usual base tables/views.
@@ -3001,8 +3001,8 @@ find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
     TODO: Ensure that table_name, db_name and tables->db always points to
           something !
   */
-  if (/* Exclude natural joins and nested joins underlying natural joins. */
-      (!(table_list->nested_join && table_list->join_columns) ||
+  if (/* Exclude nested joins. */
+      (!table_list->nested_join ||
        /* Include merge views and information schema tables. */
        table_list->field_translation) &&
       /*
@@ -3025,13 +3025,10 @@ find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
                                  register_tree_change)))
       *actual_table= table_list;
   }
-  else if (!(table_list->nested_join && table_list->join_columns))
+  else if (!table_list->nested_join)
   {
-    /*
-      'table_list' is a stored table. It is so because the only type of nested
-      join passed to this procedure is a NATURAL/USING join or an operand of a
-      NATURAL/USING join.
-    */
+    /* 'table_list' is a stored table. */
+    DBUG_ASSERT(table_list->table);
     if ((fld= find_field_in_table(thd, table_list->table, name, length,
                                   check_grants_table, allow_rowid,
                                   cached_field_index_ptr)))