relative paths in the location header are not properly redirected

[mymindishazel]

This issue is similar to nodejs/undici#1521.

Bug Description

As outlined in RFC 7231, the Location header can feature relative paths, including strings without a leading slash, like location: abc. Hackney tacks that onto the path instead of replacing the last part as described in the RFC.

Reproducible By

I noticed this while trying to use the Wikipedia API using HTTPoison, which returns relative location headers. Here's example code:

HTTPoison.start
HTTPoison.get("https://en.wikipedia.org/api/rest_v1/page/summary/coffee", [], [follow_redirect: true])

Wikipedia returns a Location: Coffee header, which:

Intended behavior

Should redirect to https://en.wikipedia.org/api/rest_v1/page/summary/Coffee

Actual behavior

Redirects to https://en.wikipedia.org/api/rest_v1/page/summary/coffee/Coffee

Or, more generally

> GET /a/b
> Host: example.com
>
< HTTP/1.1 301 Moved Permanently
< location: c

should redirect to /a/c, as defined by RFC 3986, Section 5.4 but redirects to /a/b/c in hackney.

Environment

Hackney 1.17.1
Erlang/OTP 25 [erts-13.1.1] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit] [dtrace]
Elixir 1.14.2 (compiled with Erlang/OTP 25)
Darwin Kernel Version 22.2.0: Fri Nov 11 02:06:26 PST 2022; root:xnu-8792.61.2~4/RELEASE_ARM64_T8112 arm64 / MacOS Ventura 13.1