From: Jeff King <peff@peff.net>
Date: Wed, 05 Jun 2013 22:35:51 GMT
Subject: [RFC/PATCH 0/4] real reachability checks for upload-archive
Message-ID: <20130605223551.GF8664@sigill.intra.peff.net>
In-Reply-To: <20130605163823.GE8664@sigill.intra.peff.net>

On Wed, Jun 05, 2013 at 12:38:23PM -0400, Jeff King wrote:

>   2. Actually do a reachability check. Doing a full object check to
>      allow fetching an arbitrary tree by sha1 is probably prohibitively
>      expensive[2], but we could allow the form "<commit>[:<path>]", check
>      that "<commit>" is reachable, and then allow arbitrary paths within
>      it.

Thinking on this more, the full reachability check is no worse than what
a clone has to do to fetch the full repository. Here's a series that
does the full check. I'm not entirely happy with the performance,
though; details are in patch 3.

I think I'd be tempted to just go the more limiting "commit is
reachable" route, instead, which would solve your case (and most sane
cases).

  [1/4]: clear parsed flag when we free tree buffers
  [2/4]: upload-archive: restrict remote objects with reachability check
  [3/4]: list-objects: optimize "revs->blob_objects = 0" case
  [4/4]: archive: ignore blob objects when checking reachability

-Peff