Re: Bad objects error since upgrading GitHub servers to 1.6.1

From: Shawn O. Pearce <spearce@spearce.org>
Date: Jan 28, 2009, 03:30 UTC
Message-ID: <20090128033020.GF1321@spearce.org>
In-Reply-To: <7v3af4yvmu.fsf@gitster.siamese.dyndns.org>

Junio C Hamano <gitster@pobox.com> wrote:

Show 18 quoted lines

> "Shawn O. Pearce" <spearce@spearce.org> writes:
> 
> > PJ Hyett <pjhyett@gmail.com> wrote:
> >> 
> >> Is there any possibility to have the server code in an upcoming
> >> release account for clients running 1.6.1?
> >
> > I can't think off-hand of a way for the server to know what version
> > the client is.  There's nothing really different in the protocol
> > between a 1.6.1 client and a v1.5.5-rc0~44^2 (introduction of
> > include-tag) or later client.
> 
> Hmm, I am puzzled.
> 
> I do not know how 41fa7d2 (Teach git-fetch to exploit server side
> automatic tag following, 2008-03-03), which is about the conversation
> between fetch-pack and upload-pack, is relevant to the issue at hand,
> which is about the conversation between send-pack and receive-pack.

Oh, right, its not.  I was pointing out that the last time the
protocol changed in a way the server can infer something about the
client, which IIRC was 41fa7d2, we still don't have a way to tell
what the client is.

> In send-pack receive-pack protocol, the server talks first before
> listening to the client, and the .have data is in this first part of the
> conversation.

But as you rightly point out, that's the real problem. Since the server talks first, there's no way for the server to avoid giving out the newer ".have" lines to a buggy client, as it knows nothing at all about the client. Not even its capabilities.

PJ - the short story here is, to forever work around these buggy 1.6.1 clients, you'd have to either run an old server forever, or forever run a patched server that disables the newer ".have" extension in the advertised data written by git-upload-pack. There just isn't a way to hide this from the client.

Really though, I'd recommend getting your users to upgrade to a non-buggy client. Pasky has the same problem on repo.or.cz; if he doesn't have it already he will soon when he upgrades...

-- 
Shawn.