From: Junio C Hamano <gitster@pobox.com>
Date: Fri, 07 Nov 2008 20:19:14 GMT
Subject: Re: [PATCH 2/3] Introduce rename factorization in diffcore.
Message-ID: <7v3ai3gugt.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <20081107193957.GI5158@nan92-1-81-57-214-146.fbx.proxad.net>

Yann Dirson <ydirson@altern.org> writes:

> The direct transposition of the raw output of a dir rename with a
> change would yield something like:
>
> |diff --git a/ppc/ b/foo
> |similarity index 100%
> |rename from ppc/
> |rename to foo/
> |diff --git a/ppc/sha1.h b/foo/sha1.h
> |--- ppc/sha1.h
> |+++ foo/sha1.h
> |...
>
> This would have the usefulness I'm looking for, in that the content
> modifications would not be "hidden" among a whole lot af individual
> file rename hunks.

I am afraid that this is totally unacceptable, as you yourself mentioned,
the end result is unapplicable with any existing tool and would confuse
viewers like gitk and gitweb.

I think it would be a much better approach to emit a hint that talks about
directory rename in a format that does not fool usual "patch" application
tools.  E.g.

|directory moved with similarity index 82%
|rename from ppc
|rename from foo
|diff --git a/ppc/sha1.h b/foo/sha1.h
|similarity index 85%
|rename from ppc/sha1.h
|rename to foo/sha1.h
|index  9b34f76..8fce4b7 100644
|--- ppc/sha1.h
|+++ foo/sha1.h
|@@ ...

IOW, do not add anything that begins with "diff --git" if it is not a
patch.