do not count original request for RedirectLoop protection

[oczkers]

There are many situations when servers redirects to other resource and back so we cannot be so strict here. For example:
https://some.url/protected -> 302 your login token has expired so you have to refresh it
https://some.url/refreshToken -> 302 new token is set in cookies, redirecting back to original url
https://some.url/protected -> 200, request complete

I know this isn't good approach and servers probably should be doing this without asking client/browser but this is life and currently there is no way to use httpx for this kind of sites.

[tomchristie]

Okay, so the first thing to check with this kind of change is prior art...

• How does requests handle these cases?
• How does urllib3 handle these cases (potentially different since requests doesn’t use urllib3’s built-in redirect behaviour)
• How does curl handle these cases?

[oczkers]

urllib3: By default max 3 retries, max 3 redirects, no url tracking.
requests: By default max 0 retries, max 30 redirects, no url tracking.
curl: By default 0 retries, 0 redirects

None of those (not sure about curl, haven't analyzed code) implemented this kind of protection, they simply rely on number of redirects like browsers do.

[tomchristie]

In that case I'd probably suggest we instead just drop our RedirectLoop checking completely, and adopt the same behaviour.

[oczkers]

You're probably right and this can be problematic with really wrong designed websites but considering that no one yet reported any we might keep it until someone finds one. I really like this idea, might be helpful tracking mistakes :-).

[oczkers]

I force pushed because forgot about Client, now it's changed in both async and sync client.

[tomchristie]

Given that neither urllib3 nor requests implement redirect loop checking I don't think we should either, at least at this point in time. The change here looks reasonable, but I reckon we should instead just drop the RedirectLoop exception and check altogether.