find_entries_for_url did (urlparse(url).hostname or "").lower() unguarded. a
malformed authority (e.g. an unterminated ipv6 bracket "https://[::1") makes
urlparse/hostname raise ValueError, so instead of the empty list the function
already returns for a host-less url, a raw ValueError leaked out of the shared
http client (build_request / open_url call this before any url validation).
no auth entry can match such a url, so treat it like the host-less case and
return no matches. added a regression test over an unterminated bracket and a
bracketed non-ip host; confirmed it fails on the pre-fix code.
74d03a2814