From: Jeff King <peff@peff.net>
Date: Thu, 12 Jan 2012 02:51:26 GMT
Subject: Re: [PATCH 1/2] get_sha1_with_context: report features used in resolution
Message-ID: <20120112025126.GA25365@sigill.intra.peff.net>
In-Reply-To: <7vmx9t4pgj.fsf@alter.siamese.dyndns.org>

On Wed, Jan 11, 2012 at 06:36:12PM -0800, Junio C Hamano wrote:

> Jeff King <peff@peff.net> writes:
> 
> > Most callers generally treat get_sha1 as a black box, giving
> > it a string from the user and expecting to get a sha1 in
> > return. The get_sha1_with_context function gives callers
> > more information about what happened while resolving the
> > object name so they can make better decisions about how to
> > use the result. We currently use this only to provide
> > information about the path entry used to find a blob.
> >
> > We don't currently provide any information about the
> > resolution rules that were used to reach the final object.
> > Some callers may want these in order to enforce a policy
> > that a particular subset of the lookup rules are used (e.g.,
> > when serving remote requests).
> >
> > This patch adds a set of bit-fields that document the use of
> > particular features during an object lookup.
> >
> > Signed-off-by: Jeff King <peff@peff.net>
> > ---
> > The diffstat looks a little scary, but it is mostly just the internal
> > get_sha1 functions learning to pass the object_context around.
> 
> Hmm, shouldn't this also cover peel_to_type()?  That would have made it
> also apply to the maintenance track.

I don't see how peel_to_type is relevant. As far as get_sha1 is
concerned, the interesting thing is actually calling peel_onion. It does
get the context passed to it in my patch, but I didn't bother marking
that the peel feature was used (because it wasn't relevant to the policy
I wanted to implement in the follow-on patch).

But we could pretty easily mark the use of the peel feature, too.

I'm not sure what you mean about the maintenance track, though. AFAICT,
we don't separately call peel_to_type, but just potentially use it as
part of get_sha1_with_context. Am I missing something?

-Peff