Re: [PATCH v3 1/1] protocol: advertise multiple supported versions
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Nov 14, 2018, 02:38 UTC
- Message-ID
- <xmqq1s7os7rz.fsf@gitster-ct.c.googlers.com>
- In-Reply-To
- <20181113225320.GG126896@google.com>
Josh Steadmon <steadmon@google.com> writes:
Show 16 quoted lines
> On 2018.11.13 13:01, Junio C Hamano wrote: >> steadmon@google.com writes: >> >> > Currently the client advertises that it supports the wire protocol >> > version set in the protocol.version config. However, not all services >> > support the same set of protocol versions. When connecting to >> > git-receive-pack, the client automatically downgrades to v0 if >> > config.protocol is set to v2, but this check is not performed for other >> > services. >> >> "downgrades to v0 even if ... is set to v2" you mean? Otherwise it >> is unclear why asking for v2 leads to using v0. > > The downgrade on push happens only when the the configured version is > v2. If v1 is requested, no downgrade is triggered. I'll clarify the > commit message in the next version.
OK, then it will still be confusing unless "we downgrade v2 to v0 because ..."gives the reason.
> In any case, the ordering of the server's allowed versions won't matter; > we'll pick the the first version in the client's list which is also > allowed on the server.
That sounds like a very sensible semantics.
Show 10 quoted lines
> >> I am wondering if the code added by this patch outside this >> function, with if (strcmp(client_ad.buf, "version=0") sprinkled all >> over the place, works sensibly when the other side says "I prefer >> version=0 but I do not mind talking version=1". > > Depends on what you mean by "sensibly" :). In the current case, if the > client prefers v0, it will always end up using v0. After the fixes > described above, it will always use v0 unless the server no longer > supports v0. Is that what you would expect?
Yes, that sounds like a sensible behaviour.
What I was alludding to was a lot simpler, though. An advert string "version=0:version=1" from a client that prefers version 0 won't be !strcmp("version=0", advert) but seeing many strcmp() in the patch made me wonder.