Fix for BUG#5705: "SET CHARATER_SET_SERVERetc will be lost if STOP SLAVE before following query":

we do not increment rli->group_master_log_pos if we are just after a SET ONE_SHOT (it's not a standalone event)

mysql-test/r/rpl_charset.result

@@ -198,4 +198,12 @@ CDF32C20E7E020F0FBE1E0EBEAF3	CDF32C20E7E020F0FBE1E0EBEAF3
 select hex(c1), hex(c2) from t1;
 hex(c1)	hex(c2)
 CDF32C20E7E020F0FBE1E0EBEAF3	CDF32C20E7E020F0FBE1E0EBEAF3
+stop slave;
+delete from t1;
+change master to master_log_pos=5801;
+start slave until master_log_file='master-bin.000001', master_log_pos=5937;
+start slave;
+select hex(c1), hex(c2) from t1;
+hex(c1)	hex(c2)
+CDF32C20E7E020F0FBE1E0EBEAF3	CDF32C20E7E020F0FBE1E0EBEAF3
 drop table t1;

mysql-test/t/rpl_charset.test

@@ -148,6 +148,24 @@ INSERT INTO t1 (c1, c2) VALUES ('
 select hex(c1), hex(c2) from t1;
 sync_slave_with_master;
 select hex(c1), hex(c2) from t1;
+
+# Now test for BUG##5705: SET CHARATER_SET_SERVERetc will be lost if
+# STOP SLAVE before following query
+
+stop slave;
+delete from t1;
+change master to master_log_pos=5801;
+start slave until master_log_file='master-bin.000001', master_log_pos=5937;
+# Slave is supposed to stop _after_ the INSERT, even though 5937 is
+# the position of the beginning of the INSERT; after SET slave is not
+# supposed to increment position.
+wait_for_slave_to_stop;
+# When you merge this into 5.0 you will have to adjust positions
+# above; the first master_log_pos above should be the one of the SET,
+# the second should be the one of the INSERT.
+start slave;
+sync_with_master;
+select hex(c1), hex(c2) from t1;
 connection master;
 drop table t1;
 sync_slave_with_master;

sql/log_event.cc

@@ -1091,7 +1091,15 @@ end:
   VOID(pthread_mutex_unlock(&LOCK_thread_count));
   close_thread_tables(thd);      
   free_root(&thd->mem_root,MYF(MY_KEEP_PREALLOC));
-  return (thd->query_error ? thd->query_error : Log_event::exec_event(rli)); 
+  /*
+    If there was an error we stop. Otherwise we increment positions. Note that
+    we will not increment group* positions if we are just after a SET
+    ONE_SHOT, because SET ONE_SHOT should not be separated from its following
+    updating query.
+  */
+  return (thd->query_error ? thd->query_error : 
+          (thd->one_shot_set ? (rli->inc_event_relay_log_pos(get_event_len()),0) :
+           Log_event::exec_event(rli))); 
 }
 #endif