Re: RFC 9113 and :authority header field

[Martin Thomson <[e-mail]>]

On Wed, Jun 29, 2022, at 09:58, Tatsuhiro Tsujikawa wrote:
> I think 2) is valid in terms of RFC 7540, but it suddenly becomes 
> invalid in terms of RFC 9113?
> Is this correct?  https://www.fastly.com and https://www.google.com now 
> reject 2).

My understanding is that both are valid alternatives.  As would a third option that contained the same value in both host and :authority.  The 4xx responses you are getting are (probably) compliance bugs.

Thankfully we know people who might be closer to someone who is able to fix or defend those bugs.  (On CC).

This whole host and :authority thing was an original mistake in HTTP/2.  It was grounded in the view that HTTP/2 had to faithfully capture every weird thing HTTP/1.1 could express, even when it didn't make sense.  At the time, that was pragmatic and it might have aided deployment into systems that were, on some levels, broken.  In time, we should seek to remove those exceptions.  In the revision, we did some of that by disallowing different values.