From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 16 Sep 2009 22:52:37 GMT
Subject: Re: [RFC/PATCH 0/2] Speed up fetch with large number of tags
Message-ID: <7vtyz2wlhm.fsf@alter.siamese.dyndns.org>
In-Reply-To: <20090916224253.GB14660@spearce.org>

"Shawn O. Pearce" <spearce@spearce.org> writes:

> JGit depends on the fact that the refs list is sorted by the remote
> peer, and that foo^{} immediately follows foo.  I don't think this
> has ever been documented, but all sane implementations[1] follow
> this convention and it may be something we could simply codify as
> part of the protocol standard.
>
> [1] Sane implementations are defined to be what I consider to be
>     the two stable implementations in deployed use, git.git and JGit.

There is no strong reason for ordering of refs between themselves
(i.e. refs/heads/master comes before refs/heads/next) other than the fact
that we sort and then walk due to packed-refs reasons.

But emitting tag X and then its peeled representation X^{} immediately
after it is quite fundamental in the way how anybody sane would implement
ls-remote.  There is no reason to violate the established order other than
"I could do so", and in order not to show X and X^{} next to each other,
you would need _more_ processing.

So I would say it is very safe to assume this.

Also, you might not have noticed, but my illustration patch was merely
using it as a hint to optimize, and if the last ref we saw was not X when
it is turn to handle X^{}, it simply falled back to the original logic,
iow, the patch never compromised the correctness.