Re: upload-pack/ls-remote: showing non-HEAD symbolic refs?

From: Jeff King <peff@peff.net>
Date: Aug 16, 2016, 18:28 UTC
Message-ID: <20160816182852.inyqzplee5m3wzt6@sigill.intra.peff.net>
In-Reply-To: <20160816173444.rpqlpsz2ognvlufy@x>

On Tue, Aug 16, 2016 at 10:34:44AM -0700, Josh Triplett wrote:

Show 16 quoted lines

> > Sadly you cannot use a capability to fix that, because all of this
> > happens before the client agrees to any capabilities (you can find
> > discussion of a "v2" protocol on the list which solves this, but it's
> > sort of languishing in the design phase).
> 
> As a potential 1.1 version, which could work in a backward-compatible
> way with existing servers and no additional round-trip: what if, in the
> smart HTTP protocol, the client advertised client capabilities with an
> additional HTTP header (e.g.  "Git-Client-Caps: symrefs othershiny
> featurenames"?  git-http-backend could then pass those capabilities to
> git-upload-pack (--client-caps='...'), which could take them into
> account in the initial response?
> 
> That wouldn't work as a single-pass approach for SSH, since the client
> can't know if the server's upload-pack supports --client-caps, but it
> would work for the smart HTTP protocol.

You can dig up the discussion on the list under the name "protocol v2", but basically yes, that approach has been considered. It's a little gross just because it leaves other protocols behind http (and it is not necessarily a good idea to push people into http, because it has some fundamental drawbacks over the other protocols because of its half-duplex nature).

Show 5 quoted lines

> > That should Just Work over the existing http protocol without requiring
> > an extra request.
> 
> It'd require one extra request for git ls-remote, which normally doesn't
> need the second round-trip, but that still seems reasonable.

Good point. I don't think there's an easy way around that short of v2 or v1.1 that you mention above. I agree it's probably reasonable, though.

-Peff