A fix (Bug #5232: CREATE TABLE ... SELECT can deadlock itself).

mysql-test/r/merge.result

@@ -610,3 +610,12 @@ x	y
 1	3
 1	2
 drop table t1,t2,t3;
+create table t1 (a int);
+create table t2 (a int);
+insert into t1 values (0);
+insert into t2 values (1);
+create table t3 engine=merge union=(t1, t2) select * from t1;
+INSERT TABLE 't1' isn't allowed in FROM table list
+create table t3 engine=merge union=(t1, t2) select * from t2;
+INSERT TABLE 't2' isn't allowed in FROM table list
+drop table t1, t2;

mysql-test/t/merge.test

@@ -250,3 +250,17 @@ select * from t3 where x = 1 and y < 5 order by y;
 # Bug is that followng query returns empty set while it must be same as above
 select * from t3 where x = 1 and y < 5 order by y desc;
 drop table t1,t2,t3;
+
+#
+# Bug#5232: CREATE TABLE ... SELECT
+#
+
+create table t1 (a int);
+create table t2 (a int);
+insert into t1 values (0);
+insert into t2 values (1);
+--error 1093
+create table t3 engine=merge union=(t1, t2) select * from t1;
+--error 1093
+create table t3 engine=merge union=(t1, t2) select * from t2;
+drop table t1, t2;

sql/sql_parse.cc

@@ -1655,6 +1655,19 @@ mysql_execute_command(void)
 	net_printf(&thd->net,ER_INSERT_TABLE_USED,tables->real_name);
 	DBUG_VOID_RETURN;
       }
+      if (lex->create_info.used_fields & HA_CREATE_USED_UNION)
+      {
+        TABLE_LIST *tab;
+        for (tab= tables; tab; tab= tab->next)
+        {
+          if (check_dup(tables->db, tab->real_name,
+                        (TABLE_LIST*)lex->create_info.merge_list.first))
+          {
+            net_printf(&thd->net, ER_INSERT_TABLE_USED, tab->real_name);
+            DBUG_VOID_RETURN;
+          }
+        }  
+      }    
       if (tables->next)
       {
 	TABLE_LIST *table;