From: Jeff King <peff@peff.net>
Date: Wed, 20 Jan 2016 01:34:36 GMT
Subject: Re: [PATCH] filter-branch: resolve $commit^{tree} in no-index case
Message-ID: <20160120013436.GA24541@sigill.intra.peff.net>
In-Reply-To: <20160120012253.GD16090@google.com>

On Tue, Jan 19, 2016 at 05:22:53PM -0800, Jonathan Nieder wrote:

> > I'm actually a little iffy on it because it switches to "diff-tree" from
> > a raw-sha1 comparison. For a well-formed repo, that shouldn't matter.
> > But what if you had a commit that was replacing a malformed tree object,
> > but not otherwise changing the diff?  We might drop it as "empty", even
> > though you'd prefer to keep it.
> 
> Mph.  We could get the best of both worlds by introducing a "git
> rev-parse --compare <a> <b>" that compares object ids.  Actually...
> 
> How about something like this?

Thanks. I had in my head that we could do something like that, but
hadn't quite worked it out. I think what you wrote works.

If you want to wrap it up into a patch, I'd be OK with it, but note that
it still falls afoul of changing $tree in a user-visible way (so you
should note that in the commit message).

-Peff