Bug#36312880 Gtid_tagged_log_event encodes incorrect value of original commit timestamp

Problem
-------

When original commit timestamp is equal to immediate commit timestamp,
Gtid_tagged_log_event will encode a correct value. Otherwise,
Gtid_tagged_log_event will encode the value of immediate commit
timestamp as original commit timestamp. Encoding condition is inverted.

Solution
--------

Fixed encoding condition.

Change-Id: Icfe226913e75f3d75da394d24d6b33bc2188655b

Author: Karolina Szczepankiewicz

libs/mysql/binlog/event/control_events.h

@@ -1160,7 +1160,7 @@ class Gtid_event : public Binary_log_event,
         mysql::serialization::define_field(immediate_commit_timestamp),
         mysql::serialization::define_field(
             original_commit_timestamp, Field_encode_predicate([this]() -> bool {
-              return this->original_commit_timestamp ==
+              return this->original_commit_timestamp !=
                      this->immediate_commit_timestamp;
             })),
         mysql::serialization::define_field(transaction_length),

mysql-test/suite/binlog_gtid/r/binlog_gtid_tagged_log_event_encoding.result

@@ -0,0 +1,19 @@
+RESET BINARY LOGS AND GTIDS;
+
+# T1.1 - T1.2
+
+SET SESSION original_commit_timestamp = 1;
+SET GTID_NEXT= "11111111-1111-1111-1111-111111111111:tag:1";
+CREATE TABLE t1 (a INT);
+
+# T1.3
+
+include/rpl/save_binlog_file_position.inc
+include/assert_grep.inc [Check that original commit timestamp value equals 1]
+include/assert_grep.inc [Check that immediate commit timestamp differs from original commit timestamp]
+
+# Clean up
+
+SET SESSION original_commit_timestamp = DEFAULT;
+SET GTID_NEXT='AUTOMATIC';
+DROP TABLE t1;

mysql-test/suite/binlog_gtid/t/binlog_gtid_tagged_log_event_encoding.test

@@ -0,0 +1,71 @@
+# ==== PURPOSE ====
+#
+# This test validates encoding and decoding of the GTID_TAGGED_LOG_EVENT, in
+# particular, encoded value of original commit timestamp
+#
+# ==== REQUIREMENTS ====
+#
+# When original commit timestamp value differs from immediate commit timestamp,
+# the server shall encode original commit timestamp in the GTID_TAGGED_LOG_EVENT
+#
+# ==== IMPLEMENTATION ====
+#
+# T1.
+#     Test steps:
+#
+#     1. Set up a custom original commit timestamp
+#     2. Execute transaction with a tagged GTID
+#     3. Check with mysqlbinlog that event has the required original commit
+#        timestamp value
+#
+#     Test pass conditions:
+#     - Step 3
+#
+# ==== REFERENCES ====
+#
+# Bug#36312880 Gtid_tagged_log_event encodes incorrect value of original commit
+#              timestamp
+#
+
+# This test is independent from binlog format
+--source include/have_binlog_format_row.inc
+
+RESET BINARY LOGS AND GTIDS;
+
+--echo
+--echo # T1.1 - T1.2
+--echo
+
+SET SESSION original_commit_timestamp = 1;
+
+SET GTID_NEXT= "11111111-1111-1111-1111-111111111111:tag:1";
+CREATE TABLE t1 (a INT);
+
+--echo
+--echo # T1.3
+--echo
+
+--source include/rpl/save_binlog_file_position.inc
+--let $output_file=$MYSQLTEST_VARDIR/tmp/binlog_gtid_tagged_log_event_encoding.output
+--exec $MYSQL_BINLOG --force-if-open $binlog_fullpath > $output_file
+
+--let $assert_text= Check that original commit timestamp value equals 1
+--let $assert_file = $output_file
+--let $assert_select = session.original_commit_timestamp=1\*
+--let $assert_count = 1
+--source include/assert_grep.inc
+
+--let $assert_text= Check that immediate commit timestamp differs from original commit timestamp
+--let $assert_file = $output_file
+--let $assert_select = session.immediate_commit_timestamp=1\*
+--let $assert_count = 0
+--source include/assert_grep.inc
+
+--echo
+--echo # Clean up
+--echo
+
+SET SESSION original_commit_timestamp = DEFAULT;
+SET GTID_NEXT='AUTOMATIC';
+DROP TABLE t1;
+--remove_file $output_file