Bug #15355: Common natural join column not resolved in prepared statement nested

  query
Problem:
There was a wrong context assigned to the columns that were added in insert_fields()
when expanding a '*'. When this is done in a prepared statement it causes 
fix_fields() to fail to find the table that these columns reference.
Actually the right context is set in setup_natural_join_row_types() called at the 
end of setup_tables(). However when executed in a context of a prepared statement
setup_tables() resets the context, but setup_natural_join_row_types() was not
setting it to the correct value assuming it has already done so.

Solution:
The top-most, left-most NATURAL/USING join must be set as a 
first_name_resolution_table in context even when operating on prepared statements.

mysql-test/r/join.result

@@ -744,3 +744,23 @@ select a2 from ((t1 natural join t2) join t3 on b=c1) natural join t4;
 a2
 1
 drop table t1,t2,t3,t4;
+create table t1 (c int, b int);
+create table t2 (a int, b int);
+create table t3 (b int, c int);
+create table t4 (y int, c int);
+create table t5 (y int, z int);
+insert into t1 values (3,2);
+insert into t2 values (1,2);
+insert into t3 values (2,3);
+insert into t4 values (1,3);
+insert into t5 values (1,4);
+prepare stmt1 from "select * from ((t3 natural join (t1 natural join t2))
+natural join t4) natural join t5";
+execute stmt1;
+y	c	b	a	z
+1	3	2	1	4
+select * from ((t3 natural join (t1 natural join t2)) natural join t4)
+natural join t5;
+y	c	b	a	z
+1	3	2	1	4
+drop table t1, t2, t3, t4, t5;

mysql-test/t/join.test

@@ -563,4 +563,29 @@ select a2 from ((t1 natural join t2) join t3 on b=c1) natural join t4;
 
 drop table t1,t2,t3,t4;
 
+#
+# BUG#15355: Common natural join column not resolved in prepared statement nested query
+#
+create table t1 (c int, b int);
+create table t2 (a int, b int);
+create table t3 (b int, c int);
+create table t4 (y int, c int);
+create table t5 (y int, z int);
+
+insert into t1 values (3,2);
+insert into t2 values (1,2);
+insert into t3 values (2,3);
+insert into t4 values (1,3);
+insert into t5 values (1,4);
+
+-- this fails
+prepare stmt1 from "select * from ((t3 natural join (t1 natural join t2))
+natural join t4) natural join t5";
+execute stmt1;
+
+-- this works
+select * from ((t3 natural join (t1 natural join t2)) natural join t4)
+  natural join t5;
+drop table t1, t2, t3, t4, t5;
+
 # End of tests for WL#2486 - natural/using join

sql/sql_base.cc

@@ -4184,10 +4184,6 @@ static bool setup_natural_join_row_types(THD *thd,
   if (from_clause->elements == 0)
     return FALSE; /* We come here in the case of UNIONs. */
 
-  /* For stored procedures do not redo work if already done. */
-  if (!context->select_lex->first_execution)
-    return FALSE;
-
   List_iterator_fast<TABLE_LIST> table_ref_it(*from_clause);
   TABLE_LIST *table_ref; /* Current table reference. */
   /* Table reference to the left of the current. */
@@ -4200,6 +4196,9 @@ static bool setup_natural_join_row_types(THD *thd,
   {
     table_ref= left_neighbor;
     left_neighbor= table_ref_it++;
+    /* For stored procedures do not redo work if already done. */
+    if (context->select_lex->first_execution)
+    {
       if (store_top_level_join_columns(thd, table_ref,
                                        left_neighbor, right_neighbor))
         return TRUE;
@@ -4209,6 +4208,7 @@ static bool setup_natural_join_row_types(THD *thd,
         first_leaf_on_the_right= table_ref->first_leaf_for_name_resolution();
         left_neighbor->next_name_resolution_table= first_leaf_on_the_right;
       }
+    }
     right_neighbor= table_ref;
   }