BUG#5390 - problems with merge tables

Problem #1: INSERT...SELECT, Version for 5.1.
Extended the unique table check by a check of lock data.
Merge sub-tables cannot be detected by doing name checks only.

mysql-test/r/merge.result

@@ -722,3 +722,52 @@ SELECT b FROM t2;
 b
 3
 DROP TABLE t1, t2;
+create table t1(a int);
+create table t2(a int);
+insert into t1 values (1);
+insert into t2 values (2);
+create table t3 (a int) engine=merge union=(t1, t2) insert_method=first;
+select * from t3;
+a
+1
+2
+insert t2 select * from t2;
+select * from t2;
+a
+2
+2
+insert t3 select * from t1;
+select * from t3;
+a
+1
+1
+2
+2
+insert t1 select * from t3;
+select * from t1;
+a
+1
+1
+1
+1
+2
+2
+select * from t2;
+a
+2
+2
+select * from t3;
+a
+1
+1
+1
+1
+2
+2
+2
+2
+check table t1, t2;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+test.t2	check	status	OK
+drop table t1, t2, t3;