Long unique keys are not created when individual key_part->length < max_key_length but SUM(key_parts->length) > max_key_length

--source include/have_innodb.inc

CREATE TABLE t1 (a int, b VARCHAR(1000), UNIQUE (a,b)) ENGINE=MyISAM;

show index from t1;

# Cleanup

DROP TABLE t1;

CREATE TABLE t1 (a int, b VARCHAR(1000), UNIQUE (a,b)) ENGINE=MyISAM;

main.xyz 'innodb'                 [ fail ]

        Test ended at 2020-05-26 18:39:24

CURRENT_TEST: main.mdev_21834

mysqltest: At line 2: query 'CREATE TABLE t1 (a int, b VARCHAR(1000), UNIQUE (a,b)) ENGINE=MyISAM' failed: 1071: Specified key was too long; max key length is 1000 bytes