Re: [PATCH/RFC 4/6] transport: add refspec list parameters to functions

[Junio C Hamano <gitster@pobox.com>]

Jeff King <peff@peff.net> writes:

>> What the code tries to do I am more than halfway happy.  It is
>> unfortunate that we cannot do this natively without upgrading the
>> protocol in a fundamental way, but this is a nice way to work it
>> around only for Git-over-HTTP transport without having to break the
>> protocol.
>
> I dunno, I am a bit negative on bringing new features to Git-over-HTTP
> (which is already less efficient than the other protocols!) without any
> plan for supporting them in the other protocols.
>
> I thought Stefan's v2 protocol work looked quite good, but it seems to
> have stalled. The hardest part of that topic is figuring out the upgrade
> path. But for git-over-http, we can solve that in the same way that
> David is passing in the extra refspecs.

Yeah, I had the same feeling.

> So I'd rather see something like:
>
>   1. Support for v2 "capabilities only" initial negotiation, followed
>      by ref advertisement.
>
>   2. Support for refspec-limiting capability.
>
>   3. HTTP-only option from client to trigger v2 on the server.

I like that; reducing the initial scope of v2 so that we can do this
new feature as its first use case would be a good way to move things
forward.

> That's still HTTP-specific, but it has a clear path for converging with
> the ssh and git protocols eventually, rather than having to support
> magic out-of-band capabilities forever.
>
> It does require an extra round of HTTP request/response, though.

Yes.  And as we discussed before, we can do "upload-pack" that
advertises "by the way, upload-pack-v2 is available next to me" and
a separate "upload-pack-v2" that talks v2 (i.e. its initial message
is limited to capabilities and nothing else) would probably be a
sufficient migration path for native protocol.