On Mon, 14 Sep 2009 20:28:26 +0200
Sebastian Pipping <webmaster@hartwork.org> wrote:
> Ciaran McCreesh wrote:
> > Because an overlay model has only a single foo-1.2. Think of it like
> > stacks of paper. You've got your main repository:
> > 
> >   ::gentoo    foo-1.1 foo-1.2 foo-1.3
> > 
> > and on top of that you put your overlay:
> > 
> >   ::extras          foo-1.2         foo-1.4
> >   ::gentoo  foo-1.1 foo-1.2 foo-1.3
> > 
> > and then looking down from the top, all an overlay model package
> > manager sees is the foo-1.2 from the overlay. There's no
> > foo-1.2::gentoo and foo-1.2::extras, there's just a single foo-1.2
> > that's made from (gentoo + extras).
> 
> I see.  So it would not work for dependencies but it should work for
> masking.  That alone wouldn't make me happy, though.

I don't think it would necessarily work for masking either the way
Portage sees it (although iirc it would have done for the way Pkgcore
did things). Masking doesn't make foo-1.2::extras invisible, it just
makes it visible but unusable. Even if you do take the "ignore masked
things entirely" approach, the behaviour's highly weird when things
like repository package.masks become involved -- I'm not sure you could
define a consistent model that does 'the right thing' purely on
overlays (although feel free to try...).

> > There's a different way of looking at it that focuses more on the
> > repository level view at [1].
> > 
> > [1]:
> > http://ciaranm.wordpress.com/2009/04/16/distributed-distribution-development-and-why-git-and-or-funtoo-is-not-it/
> 
> Interesting read.  Can you think of anything technical that would make
> moving portage to this model impossible?

Other than the usual problems with moving Portage to things? No. The
multiple repository model works fine with Gentoo, and it's possible to
set it up so that it looks to the user exactly like an overlay model
except where ::repo deps are involved.

-- 
Ciaran McCreesh