LPAD/RPAD with an empty padstr return NULL (MySQL returns the original string)

SELECT LPAD('abc', 10, ''), RPAD('abc', 10, '');
– MariaDB: NULL NULL <-- empty padstr makes the whole function NULL
– MySQL: abc abc <-- returns the original string when padding is impossible/unneeded
SELECT LPAD('abc', 3, '') AS l2; – length already satisfied, no pad needed at all:
– MariaDB: NULL MySQL: abc