Description:
https://dev.mysql.com/doc/refman/5.6/en/replication-features-current-user.html
<quote>
CURRENT_USER() or CURRENT_USER is also expanded prior to being written to the binary log when used in DROP USER, RENAME USER, GRANT, REVOKE, or ALTER EVENT.
</quote>
Partial binlog contents from the test case in 'How to repeat' section on 5.6:
| wheezy-64-bin.000001 | 697 | Query | 1 | 817 | use `test`; grant select on db.* to current_user |
| wheezy-64-bin.000001 | 817 | Query | 1 | 940 | use `test`; revoke select on db.* from current_user |
| wheezy-64-bin.000001 | 940 | Query | 1 | 1076 | use `test`; SET PASSWORD FOR 'u1'@'%'='*94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29' |
| wheezy-64-bin.000001 | 1076 | Query | 1 | 1187 | use `test`; rename user current_user to u2 |
| wheezy-64-bin.000001 | 1187 | Query | 1 | 1298 | use `test`; rename user u2 to current_user |
| wheezy-64-bin.000001 | 1298 | Query | 1 | 1401 | use `test`; drop user current_user |
... and on 5.7:
| wheezy-64-bin.000001 | 606 | Anonymous_Gtid | 1 | 671 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| wheezy-64-bin.000001 | 671 | Query | 1 | 789 | use `test`; GRANT SELECT ON `db`.* TO 'u1'@'%' |
| wheezy-64-bin.000001 | 789 | Anonymous_Gtid | 1 | 854 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| wheezy-64-bin.000001 | 854 | Query | 1 | 977 | use `test`; revoke select on db.* from current_user |
| wheezy-64-bin.000001 | 977 | Anonymous_Gtid | 1 | 1042 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| wheezy-64-bin.000001 | 1042 | Query | 1 | 1215 | use `test`; ALTER USER 'u1'@'%' IDENTIFIED WITH 'mysql_native_password' AS '*94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29' |
| wheezy-64-bin.000001 | 1215 | Anonymous_Gtid | 1 | 1280 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| wheezy-64-bin.000001 | 1280 | Query | 1 | 1391 | use `test`; rename user current_user to u2 |
| wheezy-64-bin.000001 | 1391 | Anonymous_Gtid | 1 | 1456 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| wheezy-64-bin.000001 | 1456 | Query | 1 | 1567 | use `test`; rename user u2 to current_user |
| wheezy-64-bin.000001 | 1567 | Anonymous_Gtid | 1 | 1632 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| wheezy-64-bin.000001 | 1632 | Query | 1 | 1735 | use `test`; drop user current_user
So, in 5.6 CURRENT_USER is only expanded in SET PASSWORD, in all other statements it goes into the binary log as is.
In 5.7, it's also expanded for GRANT (or rather, original GRANT is substituted by a generated event); but for other statements it is not.
It still replicates all right, some internal magic allows to work with the right CURRENT_USER; but replaying the binlog via mysqlbinlog => mysql breaks the contents.
Maybe it's just a documentation issue (then please re-qualify it as such), although not being able to restore from the binlog is sad.
How to repeat:
--source include/master-slave.inc
--source include/have_binlog_format_mixed.inc
--enable_connect_log
create user u1;
grant all on *.* to u1 with grant option;
--connect(con1,localhost,u1,,)
grant select on db.* to current_user;
revoke select on db.* from current_user;
set password for current_user = password('test');
rename user current_user to u2;
rename user u2 to current_user;
select current_user;
drop user current_user;
show binlog events;
--disconnect con1
--connection master
select user, host from mysql.user;
--sync_slave_with_master
select user, host from mysql.user;
