Describe the bug

It used to be possible to connect to Redis using redis-cli and a connection URL with an empty username, like this:

redis-cli -u 'redis://:PASSWORD@localhost:6379/0'

However, this no longer seems to work with the redis-cli 7.0.12 I'm using right now and it responds with:

AUTH failed: WRONGPASS invalid username-password pair or user is disabled.

I found that this can be fixed by explicitly providing default as username as follows (by luck, since that doesn't appear to be documented anywhere):

redis-cli -u 'redis://default:PASSWORD@localhost:6379/0'

However, that seems to somewhat violate the backwards compatibility promise as described here.

To reproduce

See description.

Expected behavior

See description.

Additional information

N/A