[#MDEV-32805] replication from timestamp to datetime cannot succeed (even with slave_type_conversions='ALL

When a replica has a dataype changed from timestamp to datetime it stops the replication even under slave_type_conversions='ALL_LOSSY';

In a non-replication situation conversion occurs without even a warning:

MariaDB [test]> create table t (t timestamp default now());

Query OK, 0 rows affected (0.001 sec)

MariaDB [test]> create table d (d datetime);

Query OK, 0 rows affected (0.001 sec)

MariaDB [test]> insert into t() values (),(),();

Query OK, 3 rows affected (0.001 sec)

Records: 3  Duplicates: 0  Warnings: 0

MariaDB [test]> select * from t;

+---------------------+

| t                   |

+---------------------+

| 2023-11-15 11:57:57 |

| 2023-11-15 11:57:57 |

| 2023-11-15 11:57:57 |

+---------------------+

3 rows in set (0.001 sec)

MariaDB [test]> select * from d;

+---------------------+

| d                   |

+---------------------+

| 2023-11-15 11:57:57 |

| 2023-11-15 11:57:57 |

| 2023-11-15 11:57:57 |

+---------------------+

3 rows in set (0.001 sec)

MariaDB [test]> insert into d select t from t;

Query OK, 3 rows affected (0.001 sec)

Records: 3  Duplicates: 0  Warnings: 0

MariaDB [test]> select * from d;

+---------------------+

| d                   |

+---------------------+

| 2023-11-15 11:57:57 |

| 2023-11-15 11:57:57 |

| 2023-11-15 11:57:57 |

+---------------------+

3 rows in set (0.001 sec)

Request that replication from timestamp to datetime columns occur (preferably without even a lossy requirement if appropriate).

rpl-lossy.test
--source include/master-slave.inc

connection master;

CREATE TABLE t1 (t timestamp);
INSERT INTO t1 values ('2023-11-15 11:57:57');

sync_slave_with_master;
connection slave;

SET GLOBAL slave_type_conversions='ALL_LOSSY';

ALTER TABLE t1 MODIFY t datetime;

connection master;

SET binlog_format=ROW;
INSERT INTO t1 values ('2022-01-01 01:01:01');

sync_slave_with_master;

connection slave;

SELECT * FROM t1;

SET GLOBAL slave_type_conversions=DEFAULT;
connection master;
DROP TABLE t1;
sync_slave_with_master;
--source include/rpl_end.inc

result
CURRENT_TEST: main.rpl-lossy
analyze: sync_with_master
mysqltest: At line 20: sync_slave_with_master failed: 'select master_pos_wait('master-bin.000001', 985, 300, '')' returned NULL indicating slave SQL thread failure


== /home/dan/repos/build-mariadb-server-10.4/mysql-test/var/tmp/analyze-sync_with_master-mysqld.2.err ==

############################## default ##############################

** SHOW WARNINGS on default **
SHOW WARNINGS;
Level Code Message

** SELECT replication-related variables on default **
SELECT NOW(), @@SERVER_ID;
NOW() @@SERVER_ID
2023-11-15 12:07:25 2

** SHOW SLAVE STATUS on default **
SHOW SLAVE STATUS;
...
Last_Errno 1677
Last_Error Column 0 of table 'test.t1' cannot be converted from type 'timestamp' to type 'datetime'
Skip_Counter 0

[MDEV-32805] replication from timestamp to datetime cannot succeed (even with slave_type_conversions='ALL_LOSSY') Created: 2023-11-15 Updated: 2023-12-31
Status:	Open
Project:	MariaDB Server
Component/s:	Replication
Affects Version/s:	10.4.32
Fix Version/s:	10.4, 10.6, 10.11