MDEV-26: Global transaction ID.

Fix MDEV-4329. When user does CHANGE MASTER TO
MASTER_GTID_POS='<explicit GTID state>', we check that this state
does not conflict with the binlog. But the code forgot to give an
error in the case where a domain was completely missing from the
requested position (eg. MASTER_GTID_POS='').

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

@@ -40,6 +40,8 @@ SET sql_log_bin = 1;
 INSERT INTO t1 VALUES (3);
 CHANGE MASTER TO master_gtid_pos = "0-1-1";
 ERROR HY000: Requested MASTER_GTID_POS 0-1-1 conflicts with the binary log which contains a more recent GTID 0-2-11. To use the requested MASTER_GTID_POS, the old binlog must be removed with RESET MASTER to avoid out-of-order binlog
+CHANGE MASTER TO master_gtid_pos = "";
+ERROR HY000: Requested MASTER_GTID_POS contains no value for replication domain 0. This conflicts with the binary log which contains GTID 0-2-11. To use the requested MASTER_GTID_POS, the old binlog must be removed with RESET MASTER to avoid out-of-order binlog
 RESET MASTER;
 CHANGE MASTER TO master_gtid_pos = "0-1-1";
 START SLAVE;

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

@@ -87,5 +87,29 @@ SELECT * FROM t1 ORDER BY a;
 a
 1
 2
+*** MDEV-4329: MASTER_GTID_POS='' is not checked for conflicts with binlog ***
+include/stop_slave.inc
+DROP TABLE t1;
+RESET SLAVE;
+CHANGE MASTER TO master_gtid_pos='';
+ERROR HY000: Requested MASTER_GTID_POS contains no value for replication domain 0. This conflicts with the binary log which contains GTID 0-2-4. To use the requested MASTER_GTID_POS, the old binlog must be removed with RESET MASTER to avoid out-of-order binlog
+RESET MASTER;
+CHANGE MASTER TO master_gtid_pos='';
+include/start_slave.inc
+SELECT * FROM t1 ORDER BY a;
+a
+1
+2
+include/stop_slave.inc
+SET SQL_LOG_BIN=0;
+DROP TABLE t1;
+SET SQL_LOG_BIN=1;
+RESET SLAVE;
+CHANGE MASTER TO master_gtid_pos='';
+include/start_slave.inc
+SELECT * FROM t1 ORDER BY a;
+a
+1
+2
 DROP TABLE t1;
 include/rpl_end.inc

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

@@ -71,6 +71,8 @@ INSERT INTO t1 VALUES (3);
 
 --error ER_MASTER_GTID_POS_CONFLICTS_WITH_BINLOG
 CHANGE MASTER TO master_gtid_pos = "0-1-1";
+--error ER_MASTER_GTID_POS_MISSING_DOMAIN
+CHANGE MASTER TO master_gtid_pos = "";
 RESET MASTER;
 CHANGE MASTER TO master_gtid_pos = "0-1-1";
 

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

@@ -143,6 +143,45 @@ INSERT INTO t1 VALUES (2);
 
 SELECT * FROM t1 ORDER BY a;
 
+
+--echo *** MDEV-4329: MASTER_GTID_POS='' is not checked for conflicts with binlog ***
+
+# Test starting the slave completely from scratch, deleting all tables and
+# replicating from the start of the master's binlog. This requires RESET
+# MASTER is run on the slave to avoid old junk in the binlog. The bug was
+# that the code did not catch the error of missing RESET MASTER when an
+# empty MASTER_GTID_POS='' was specified.
+
+--connection server_2
+--source include/stop_slave.inc
+DROP TABLE t1;
+RESET SLAVE;
+--error ER_MASTER_GTID_POS_MISSING_DOMAIN
+eval CHANGE MASTER TO master_gtid_pos='';
+RESET MASTER;
+eval CHANGE MASTER TO master_gtid_pos='';
+
+--source include/start_slave.inc
+--sync_with_master
+SELECT * FROM t1 ORDER BY a;
+
+
+# Same thing, but this time using SQL_LOG_BIN=0 to avoid polliting the
+# slave binlog.
+
+--connection server_2
+--source include/stop_slave.inc
+SET SQL_LOG_BIN=0;
+DROP TABLE t1;
+SET SQL_LOG_BIN=1;
+RESET SLAVE;
+eval CHANGE MASTER TO master_gtid_pos='';
+
+--source include/start_slave.inc
+--sync_with_master
+SELECT * FROM t1 ORDER BY a;
+
+
 # Clean up.
 --connection server_1
 DROP TABLE t1;

sql/share/errmsg-utf8.txt

@@ -6617,3 +6617,5 @@ ER_CANNOT_LOAD_SLAVE_GTID_STATE
 	eng "Failed to load replication slave GTID state from table %s.%s"
 ER_MASTER_GTID_POS_CONFLICTS_WITH_BINLOG
 	eng "Requested MASTER_GTID_POS %u-%u-%llu conflicts with the binary log which contains a more recent GTID %u-%u-%llu. To use the requested MASTER_GTID_POS, the old binlog must be removed with RESET MASTER to avoid out-of-order binlog"
+ER_MASTER_GTID_POS_MISSING_DOMAIN
+	eng "Requested MASTER_GTID_POS contains no value for replication domain %u. This conflicts with the binary log which contains GTID %u-%u-%llu. To use the requested MASTER_GTID_POS, the old binlog must be removed with RESET MASTER to avoid out-of-order binlog"

sql/sql_repl.cc

@@ -2533,7 +2533,12 @@ bool change_master(THD* thd, Master_info* mi, bool *master_info_added)
         if (binlog_gtid->server_id != global_system_variables.server_id)
           continue;
         if (!(slave_gtid= tmp_slave_state.find(binlog_gtid->domain_id)))
-          continue;
+        {
+          my_error(ER_MASTER_GTID_POS_MISSING_DOMAIN, MYF(0),
+                   binlog_gtid->domain_id, binlog_gtid->domain_id,
+                   binlog_gtid->server_id, binlog_gtid->seq_no);
+          break;
+        }
         if (slave_gtid->seq_no < binlog_gtid->seq_no)
         {
           my_error(ER_MASTER_GTID_POS_CONFLICTS_WITH_BINLOG, MYF(0),