Fix for BUG#16559 "Replication Problems with Non transactional tables inside an interrupted trans.":

problem was: when a connection disconnects having an open transaction affecting MyISAM and InnoDB, the ROLLBACK event stored in the binary log
contained a non-zero error code (1053 because of the disconnection), so when slave applied the transaction, slave complained that its ROLLBACK succeeded
(error_code=0) while master's had 1053, so slave stopped. But internally generated binlog events such as this ROLLBACK
should always have 0 as error code, as is true in 4.1 and was accidentally broken in 5.0,
so that there is no false alarm.

mysql-test/r/mix_innodb_myisam_binlog.result

@@ -256,3 +256,26 @@ master-bin.000001	1648	Query	1	#	use `test`; create table t2 (n int) engine=inno
 master-bin.000001	1748	Query	1	#	use `test`; DROP /*!40005 TEMPORARY */ TABLE IF EXISTS `test`.`t1`,`test`.`ti`
 do release_lock("lock1");
 drop table t0,t2;
+reset master;
+create table t1 (a int) engine=innodb;
+create table t2 (a int) engine=myisam;
+select get_lock("a",10);
+get_lock("a",10)
+1
+begin;
+insert into t1 values(8);
+insert into t2 select * from t1;
+select get_lock("a",10);
+get_lock("a",10)
+1
+select
+(@a:=load_file("MYSQL_TEST_DIR/var/tmp/mix_innodb_myisam_binlog.output"))
+is not null;
+(@a:=load_file("MYSQL_TEST_DIR/var/tmp/mix_innodb_myisam_binlog.output"))
+is not null
+1
+select
+@a like "%#%error_code=0%ROLLBACK;%ROLLBACK /* added by mysqlbinlog */;%",
+@a not like "%#%error_code=%error_code=%";
+@a like "%#%error_code=0%ROLLBACK;%ROLLBACK /* added by mysqlbinlog */;%"	@a not like "%#%error_code=%error_code=%"
+1	1

mysql-test/t/mix_innodb_myisam_binlog.test

@@ -259,5 +259,36 @@ show binlog events from 98;
 do release_lock("lock1");
 drop table t0,t2;
 
-
 # End of 4.1 tests
+
+# Test for BUG#16559 (ROLLBACK should always have a zero error code in
+# binlog). Has to be here and not earlier, as the SELECTs influence
+# XIDs differently between normal and ps-protocol (and SHOW BINLOG
+# EVENTS above read XIDs).
+
+connect (con4,localhost,root,,);
+connection con3;
+reset master;
+create table t1 (a int) engine=innodb;
+create table t2 (a int) engine=myisam;
+select get_lock("a",10);
+begin;
+insert into t1 values(8);
+insert into t2 select * from t1;
+disconnect con3;
+
+connection con4;
+select get_lock("a",10); # wait for rollback to finish
+
+# we check that the error code of the "ROLLBACK" event is 0 and not
+# ER_SERVER_SHUTDOWN (i.e. disconnection just rolls back transaction
+# and does not make slave to stop)
+--exec $MYSQL_BINLOG --start-position=547 $MYSQL_TEST_DIR/var/log/master-bin.000001 > var/tmp/mix_innodb_myisam_binlog.output
+--replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
+eval select
+(@a:=load_file("$MYSQL_TEST_DIR/var/tmp/mix_innodb_myisam_binlog.output"))
+is not null;
+--replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
+eval select
+@a like "%#%error_code=0%ROLLBACK;%ROLLBACK /* added by mysqlbinlog */;%",
+@a not like "%#%error_code=%error_code=%";

sql/log.cc

@@ -132,6 +132,7 @@ static int binlog_commit(THD *thd, bool all)
     DBUG_RETURN(0);
   }
   Query_log_event qev(thd, STRING_WITH_LEN("COMMIT"), TRUE, FALSE);
+  qev.error_code= 0; // see comment in MYSQL_LOG::write(THD, IO_CACHE)
   DBUG_RETURN(binlog_end_trans(thd, trans_log, &qev));
 }
 
@@ -156,6 +157,7 @@ static int binlog_rollback(THD *thd, bool all)
   if (unlikely(thd->options & OPTION_STATUS_NO_TRANS_UPDATE))
   {
     Query_log_event qev(thd, STRING_WITH_LEN("ROLLBACK"), TRUE, FALSE);
+    qev.error_code= 0; // see comment in MYSQL_LOG::write(THD, IO_CACHE)
     error= binlog_end_trans(thd, trans_log, &qev);
   }
   else
@@ -1826,7 +1828,9 @@ bool MYSQL_LOG::write(THD *thd, IO_CACHE *cache, Log_event *commit_event)
         Imagine this is rollback due to net timeout, after all statements of
         the transaction succeeded. Then we want a zero-error code in BEGIN.
         In other words, if there was a really serious error code it's already
-        in the statement's events.
+        in the statement's events, there is no need to put it also in this
+        internally generated event, and as this event is generated late it
+        would lead to false alarms.
         This is safer than thd->clear_error() against kills at shutdown.
       */
       qinfo.error_code= 0;