RE: i37: Vary and non-existant headers

Julian Reschke wrote:
> Brian Smith wrote:
> > Consider this:
> >
> > 1. Client requests "GET /foo"
> > 2. Cache forwards the request to the server "GET /foo" with
> >    an If-None-Match: "A", "B", "C"
> > 3. Server returns "304 Not Modified" with ETag "A".
>
> Why?
> 
> What you describe sounds like a bug.

I was thinking about what you said and I noticed this sentence in 2.6:

   If no stored response matches, the cache MAY forward the presented
   request to the origin server in a conditional request, and SHOULD
   include all ETags stored with potentially suitable responses in an
   If-None-Match request header.  

What is a "potentially suitable response"? Doesn't that just mean any or all
stored responses for that request-URI? If no stored response matches, the
cache MUST forward the presented request to the origin server (what else
could it do?), and that request SHOULD be conditional (see 2.4), right?. If
"potentially suitable responses" doesn't have any real meaning then what is
the point of this statement?

- Brian