From: Eric Sunshine <sunshine@sunshineco.com>
Date: Fri, 07 Jun 2013 00:50:27 GMT
Subject: Re: [PATCH 4/4] archive: ignore blob objects when checking reachability
Message-ID: <CAPig+cRMGBjXO3Phmv=SX7FQwZ=uCUTT9YSKiEBb6PU0ts_1uw@mail.gmail.com>
In-Reply-To: <20130605224038.GD15607@sigill.intra.peff.net>

On Wed, Jun 5, 2013 at 6:40 PM, Jeff King <peff@peff.net> wrote:
> We cannot create an archive from a blob object, so we would
> not expect anyone to provide one to us. And if they do, we
> will fail anyway just after the reachability check.  We can
> therefore optimize our reachability check to ignore blobs
> completely, and not even create a "struct blob" for them.
>
> Depending on the repository size and the exact place we find
> the reachable object in the traversal, this can save 20-25%,
> a we can avoid many lookups in the object hash.

s/a/as/

> The downside of this is that a blob provided to a remote
> archive process will fail with "no such object" rather than
> "object is not a tree" (we could organize the code to retain
> the old message, but since we no longer know whether the
> blob is reachable or not, we would potentially be leaking
> information about the existence of unreachable objects).
>
> Signed-off-by: Jeff King <peff@peff.net>