resolve_relative_location removed "." and ".." segments only from a relative-path Location. A Location that starts with "/" or an absolute URI was requested as is, so a redirect to /dir/../target went out as /dir/../target and a server that does not normalize the path answered 404.
RFC 3986 section 5.2.2 applies remove_dot_segments to the target path of every reference that has a path, and Go and urllib3 do the same. The loop now lives in detail::remove_dot_segments, and ClientImpl::redirect applies it to an absolute path as well. Relative locations resolve as before.
is_redirect treated any 3xx with a Location as a redirect, so with set_follow_location(true) a 304 or 305 that carried a Location was followed. Only 301, 302, 303, 307 and 308 are redirects a client follows (RFC 9110 section 15.4), as in Go, requests and urllib3. A Location is still required. The 304 check in process_request that is_redirect now covers is dropped.
Without keep-alive, the client sends "Connection: close", but before
following a redirect it disconnected only when the response repeated
the option. RFC 9112 (section 9.6) lets a server close the connection
without repeating it, and a client that sent "close" must not send
another request on that connection. The redirected request was written
to the closing connection and failed with "Failed to read connection"
whenever the server closed it first. The client now disconnects before
a redirect or an auth retry whenever the request asked for the close.
Co-authored-by: Wleeaf <179125857+wleeaf@users.noreply.github.com>
Wleeaf