Re: [PATCH 5/6 (v2)] upload-pack: send the HEAD information

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 1, 2008, 19:54 UTC
Message-ID: <7voczvr7qz.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <20081201162011.GI23984@spearce.org>

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

Show 17 quoted lines

> Maybe we put on the first capability line a flag that lets the
> client know we have symref data in the advertised list, and then
> instead of sticking only HEAD into that first ref we put the names
> of the symrefs after the ref they point to.
>
> So we might see something like:
>
>   xxxx......................... refs/heads/boo\0with-symref\0
>   xxxx......................... refs/heads/master\0HEAD\0
>   xxxx......................... refs/remotes/origin/HEAD\0refs/remotes/origin/master\0
>
> etc.  Its probably harder to produce the output for, but it permits
> advertising all of the symrefs on the remote side, which may be good
> for --mirror, among other uses.  It also should make it easier to put
> multiple symrefs down pointing at the same real ref, they could just
> be a space delimited list stored after the ref name, and if its the
> first ref in the stream, after the other capability advertisement.

It certainly is possible, and I think the arrangement v2 code makes already keeps that option to talk about symrefs other than HEAD open. If you want to send all the symref information, you would show something like:

    xxxx... HEAD\0<caps>\0refs/heads/master\n
    xxxx... refs/heads/master\n
    xxxx... refs/remotes/origin/HEAD\0<caps>\0refs/remotes/origin/master\n
    xxxx... refs/remotes/origin/master\n

But in this round I am not interested in giving any "random symref" information but "HEAD", so I omitted it from the code.

Notice that you need to repeat the capabilities list on each and every line that describes a symbolic ref for that to work (and you do not need "with-symref"), though. See what ll. 80-84 in connect.c does.

	if (len != name_len + 41) {
		free(server_capabilities);
		server_capabilities = xstrdup(name + name_len + 1);
	}

Historical accident mandates that the first hidden piece of information on each and all of these lines _must_ be the capabilities list.