Re: diff machinery cleanup

From: Jeff King <peff@peff.net>
Date: Aug 10, 2006, 10:38 UTC
Message-ID: <20060810103836.GA1317@coredump.intra.peff.net>
In-Reply-To: <7vejvpvsni.fsf@assigned-by-dhcp.cox.net>

On Thu, Aug 10, 2006 at 02:36:49AM -0700, Junio C Hamano wrote:

> In general, run_diff_X are _not_ designed to run twice.

OK, makes sense. As you probably guessed, the reason is for the run-status in C.

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> If you are working in "next" branch where Johannes's merge-recur
> work introduced discard_cache(), you could fake this somehow
> stashing away a copy of the original index, and once you are
> done with run_diff_index(), clean the slate by calling
> discard_cache() once you are done, and swap the original index
> in before running run_diff_files().

OK, doing a discard_cache() between the call to run_diff_index and run_diff_files seems to clear up the problem. But if I understand correctly, are you saying that run_diff_index has munged the index on disk, and I really need to be poking at a temporary copy? If so, why isn't that a problem when running (e.g.) "git-diff-index; git-ls-files"?

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> To solve this cleanly without doing the index munging hack, you
> would (actually, I would) need to have a new path walker that
> walks index, tree and working tree in parallel, which I was
> working on in the git-status/git-commit rewrite I started and
> discarded a few days ago.

That does sound the cleanest, and it would enable a more useful status message, as you mentioned before. What caused you to stop working on it? Infeasible, or simply more infeasible than you would like right now?

-Peff