On Tue, Aug 16, 2016 at 11:28 AM, Jeff King <peff@xxxxxxxx> wrote: > On Tue, Aug 16, 2016 at 10:34:44AM -0700, Josh Triplett wrote: > >> > 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). Some more thoughts on protocol v2 (the good parts to be attributed to jrnieder@xxxxxxxxx): * In case of http we can use the http header and know information about the client, i.e. if it may support the following ideas: * Instead of introducing a new protocol we introduce a capability\ "resend-ref-advertisement" and only advertise very few refs (e.g. only the branches, not the pending changes in case of Gerrit) * The client can then ignore the refs advertisement and ask for a resend of the refs with more specification, e.g. "want refs/heads/*", so allowing more than just sha1s in the want line but complex things like branch patterns. > >> > 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 > -- > To unsubscribe from this list: send the line "unsubscribe git" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html