Redis redis-cli with -n option higher than max database index appears to work but does not

As of 91685eeeb1462edfc12da2e079e76bdbeec0eddb, when e.g. databases 16 is configured, the SELECT command checks to make sure that the provided index is valid:

127.0.0.1:6379> select 500
(error) ERR DB index is out of range

But when connecting to redis with the -n command line argument appears to connect to the requested database, while actually connecting to database 0:

$ redis-cli -n 500
127.0.0.1:6379[500]> info keyspace
# Keyspace
db0:keys=1,expires=0,avg_ttl=0
127.0.0.1:6379[500]> set xyzzy plugh
OK
127.0.0.1:6379[500]> info keyspace
# Keyspace
db0:keys=2,expires=0,avg_ttl=0

This seems like confusing behavior, at best; it seems preferable for an invalid -n argument to cause the connection to fail with behavior similar to an invalid SELECT command.

Comment From: huangzhw

Fixed by https://github.com/redis/redis/pull/8898