From: Heiko Voigt <hvoigt@hvoigt.net>
Date: Mon, 14 May 2012 17:51:26 GMT
Subject: Re: git-diff-tree does not use alternate objects for submodules
Message-ID: <20120514175125.GD58058@book.hvoigt.net>
In-Reply-To: <7v7gweiu7b.fsf@alter.siamese.dyndns.org>

Hi,

On Mon, May 14, 2012 at 09:49:28AM -0700, Junio C Hamano wrote:
> Heiko Voigt <hvoigt@hvoigt.net> writes:
> 
> > Here is the simplest approach I could think of (not sure if its maybe
> > too simple). On first sight it seems to work (even if I exchange the
> > absolute path in alternates with a relative one.
> 
> Conceptually looks very sound and trivially correct as long as the
> objets_directory.buf is always absolute path (I didn't check, and I do not
> offhand know if read_info_alternates() was designed to work when called
> with a relative path in relative_base).

It looks quite so:

In read_info_alternates() the alternates file underneath the passed
relative_base is opened. It then passes it on to link_alt_odb_entries()
which itself passes it unmodified to link_alt_odb_entry().

link_alt_odb_entry() uses realpath to combine relative entries with
relative_base before recursively passing the entry to
read_info_alternates().

For entries with absolute path relative_base does not seem to be
relevant.

Cheers Heiko