From: Nicolas Pitre <nico@cam.org>
Date: Mon, 14 Jul 2008 23:39:08 GMT
Subject: Re: [BUG] commit walk machinery is dangerous !
Message-ID: <alpine.LFD.1.10.0807141937180.12484@xanadu.home>
In-Reply-To: <7vod50dote.fsf@gitster.siamese.dyndns.org>

On Mon, 14 Jul 2008, Junio C Hamano wrote:

> Nicolas Pitre <nico@cam.org> writes:
> 
> > It is those with semantic meaning (e.g. object doesn't exist) which 
> > should be audited, especially if used in the context of repository 
> > modification, which pretty much limits it to the test case I produced.
> 
> I've been wondering if we should make the change 8eca0b4 (implement some
> resilience against pack corruptions, 2008-06-23) less aggressive.
> 
> It makes loose objects and data from other packs to be used as fallback
> where we used to just punt, which is a genuine improvement for "salvaging"
> mode of operation, but at the same time, it now forbids the callers to
> expect that the objects they learned to exist from has_sha1_file() or
> nth_packed_object_sha1() should never result NULL return value from
> read_sha1_file().
> 
> It may make it safe again to fail if you cannot salvage using fallback
> method after all.  Something like the attached.

Well, I have a different solution which should restore the original 
"behavior" in the presence of existing but non-readable objects.  Patch 
will follow later.


Nicolas