see attachment. output:

URI 's://ui@%5B::0000%5D/path',
user info has to be 'ui', but 'null'
schema = 's'
ui = 'null'
host = 'null'
port = -1
path = '/path'
authority = 'ui@[::0000]'

As far as I know 'authority' IS '[userInfo@]host[:port]'.
This output shows that URI class instance can be inconsistent. It stores the same information at least twice.