Re: [PATCH 2/3] Introduce rename factorization in diffcore.

From: Yann Dirson <ydirson@altern.org>
Date: Nov 7, 2008, 20:39 UTC
Message-ID: <20081107203952.GJ5158@nan92-1-81-57-214-146.fbx.proxad.net>
In-Reply-To: <7v3ai3gugt.fsf@gitster.siamese.dyndns.org>

On Fri, Nov 07, 2008 at 12:19:14PM -0800, Junio C Hamano wrote:

> 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.

Well, other tools will still have to be taught about a new syntax, if they're going to use the new flag - just like it was for --rename.

That makes me think that it could be interesting to have a header telling which diff extensions it is using. It could even be interesting to come with a cross-vc convention, which would ease the interchange of modern patch files (I suppose some other tools already have their own extensions for file renames).

What about some hint like the following ?

|extended diff features: git:rename git:binary git:filetypes
|extended diff features: git:unixperms git:dir-rename

Maybe we could leave "filetype" and "unixperms" out, since these do not replace an information that would otherwise be present in a standard diff anyway, and would just be ignored by a tool not supporting them.

Show 15 quoted lines

> 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
> |@@ ...

So you're favoring the "patch is not textually splittable approach". Don't you think it would be good to add some sort of hint about this as a patch header ?

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

OK.