MDEV-33672: 10.11 Fix for Two Phase Alter Flags

Extends 89c907bd to account for
binlog_two_phase_alter flags in a Gtid log event. I.e., if the
FL_COMMIT_ALTER_E1 or FL_ROLLBACK_ALTER_E2 flags are set in the
event flags, yet the length of the event is too short to hold
the value, then set the event as invalid

mysql-test/suite/rpl/r/rpl_gtid_header_valid.result

@@ -112,6 +112,30 @@ RESET MASTER;
 set @@global.gtid_slave_pos="";
 include/start_slave.inc
 #
+# Test FL_COMMIT_ALTER
+connection master;
+set @old_dbug= @@SESSION.debug_dbug;
+set @@SESSION.debug_dbug= "+d,negate_alter_fl_from_gtid";
+set @old_alter_tp= @@SESSION.binlog_alter_two_phase;
+set @@SESSION.binlog_alter_two_phase= 1;
+alter table t1 add column (nc int);
+include/save_master_gtid.inc
+set @@SESSION.debug_dbug=@old_dbug;
+set @@SESSION.binlog_alter_two_phase=@old_alter_tp;
+connection slave;
+# Waiting for slave to find invalid event..
+include/wait_for_slave_sql_error.inc [errno=1594]
+STOP SLAVE IO_THREAD;
+# Reset master binlogs (as there is an invalid event) and slave state
+connection master;
+RESET MASTER;
+connection slave;
+SET STATEMENT sql_log_bin=0 FOR alter table t1 add column (nc int);
+RESET SLAVE;
+RESET MASTER;
+set @@global.gtid_slave_pos="";
+include/start_slave.inc
+#
 # Cleanup
 connection master;
 drop table t1;

mysql-test/suite/rpl/t/rpl_gtid_header_valid.test

@@ -167,6 +167,38 @@ RESET MASTER;
 set @@global.gtid_slave_pos="";
 --source include/start_slave.inc
 
+
+--echo #
+--echo # Test FL_COMMIT_ALTER
+--connection master
+set @old_dbug= @@SESSION.debug_dbug;
+set @@SESSION.debug_dbug= "+d,negate_alter_fl_from_gtid";
+set @old_alter_tp= @@SESSION.binlog_alter_two_phase;
+set @@SESSION.binlog_alter_two_phase= 1;
+alter table t1 add column (nc int);
+--source include/save_master_gtid.inc
+set @@SESSION.debug_dbug=@old_dbug;
+set @@SESSION.binlog_alter_two_phase=@old_alter_tp;
+
+--connection slave
+--echo # Waiting for slave to find invalid event..
+let $slave_sql_errno= 1594; # ER_SLAVE_RELAY_LOG_READ_FAILURE
+source include/wait_for_slave_sql_error.inc;
+STOP SLAVE IO_THREAD;
+
+--echo # Reset master binlogs (as there is an invalid event) and slave state
+--connection master
+RESET MASTER;
+
+--connection slave
+# Just to keep tables consistent between master/slave
+SET STATEMENT sql_log_bin=0 FOR alter table t1 add column (nc int);
+RESET SLAVE;
+RESET MASTER;
+set @@global.gtid_slave_pos="";
+--source include/start_slave.inc
+
+
 --echo #
 --echo # Cleanup
 

sql/log_event.cc

@@ -2688,6 +2688,11 @@ Gtid_log_event::Gtid_log_event(const uchar *buf, uint event_len,
     }
     if (flags_extra & (FL_COMMIT_ALTER_E1 | FL_ROLLBACK_ALTER_E1))
     {
+      if (event_len < static_cast<uint>(buf - buf_0) + 8)
+      {
+        seq_no= 0;
+        return;
+      }
       sa_seq_no= uint8korr(buf);
       buf+= 8;
     }

sql/log_event_server.cc

@@ -3759,7 +3759,9 @@ Gtid_log_event::write()
     write_len++;
   }
 
-  if (flags_extra & (FL_COMMIT_ALTER_E1 | FL_ROLLBACK_ALTER_E1))
+  if (flags_extra & (FL_COMMIT_ALTER_E1 | FL_ROLLBACK_ALTER_E1)
+      && !DBUG_IF("negate_alter_fl_from_gtid")
+  )
   {
     int8store(buf + write_len, sa_seq_no);
     write_len+= 8;