ONLY_FULL_GROUP_BY is ignored with derived_merge=on or merge views

CREATE TABLE t (a INT);

INSERT INTO t VALUES (1),(2);

CREATE ALGORITHM=MERGE VIEW v AS SELECT * FROM t;

SET sql_mode= 'ONLY_FULL_GROUP_BY';

SELECT a, COUNT(*) FROM v;

# Cleanup

DROP VIEW v;

DROP TABLE t;

MariaDB [test]> SET sql_mode= 'ONLY_FULL_GROUP_BY';

Query OK, 0 rows affected (0.000 sec)

MariaDB [test]> SELECT a, COUNT(*) FROM v;

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

| a    | COUNT(*) |

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

|    1 |        2 |

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

1 row in set (0.001 sec)

MariaDB [test]> SELECT a, COUNT(*) FROM t;

ERROR 1140 (42000): Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause

CREATE TABLE t (a INT);

INSERT INTO t VALUES (1),(2);

SET sql_mode= 'ONLY_FULL_GROUP_BY';

SELECT a, COUNT(*) FROM (SELECT * FROM t) sq;

SELECT a, COUNT(*) FROM (SELECT * FROM t) sq;

a	COUNT(*)

1	2

SET optimizer_switch='derived_merge=off';

SELECT a, COUNT(*) FROM (SELECT * FROM t) sq;

bug.t2                                   [ fail ]

        Test ended at 2022-01-06 18:31:10

CURRENT_TEST: bug.t2

mysqltest: At line 7: query 'SELECT a, COUNT(*) FROM (SELECT * FROM t) sq' failed: 1140: Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause