Replication:

as the I/O thread filters on the server id, we must test replicate_same_server_id in it (on top of in the SQL thread).

mysql-test/r/rpl_server_id2.result

-slave stop;
+stop slave;
 drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
 reset master;
 reset slave;
 drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
-slave start;
+start slave;
 drop table if exists t1;
+Warnings:
+Note	1051	Unknown table 't1'
 create table t1 (n int);
 reset master;
 stop slave;
 change master to master_port=SLAVE_PORT;
 show slave status;
-Master_Host	Master_User	Master_Port	Connect_retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_do_db	Replicate_ignore_db	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
-127.0.0.1	root	SLAVE_PORT	1		4	slave-relay-bin.001	4		No	No			0		0	0	#
+Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
+	127.0.0.1	root	SLAVE_PORT	1		4	slave-relay-bin.000001	4		No	No						#	0		0	0	4	None		0	No						NULL
 start slave;
 insert into t1 values (1);
 select * from t1;

sql/slave.cc

@@ -2833,11 +2833,6 @@ static int exec_relay_log_event(THD* thd, RELAY_LOG_INFO* rli)
       log files themselves.
     */
 
-    /*
-      TODO: when this is merged into 4.1, one needs to update queue_event() to
-      add a similar test for replicate_same_server_id, because in 4.1 the I/O
-      thread is also filtering events based on the server id.
-    */
     if ((ev->server_id == (uint32) ::server_id && !replicate_same_server_id) ||
 	(rli->slave_skip_counter && type_code != ROTATE_EVENT))
     {
@@ -3716,7 +3711,8 @@ int queue_event(MASTER_INFO* mi,const char* buf, ulong event_len)
      direct master (an unsupported, useless setup!).
   */
 
-  if (uint4korr(buf + SERVER_ID_OFFSET) == ::server_id)
+  if ((uint4korr(buf + SERVER_ID_OFFSET) == ::server_id) &&
+      !replicate_same_server_id)
   {
     /*
       Do not write it to the relay log.