Re: [gentoo-dev] Packages pulling in python-3*, also they dont require it

[Ciaran McCreesh]

On Thu, 18 Mar 2010 23:00:56 +0200
Petteri Räty <betelgeuse@g.o> wrote:
> >> Here's how we could change Portage behavior for pulling new slots
> >> that are not strictly required:
> >>
> >> - for packages in the world file install as soon as available
> >>
> >> - for dependencies install the new slot if everything works with
> >> the new slot
> >>
> >> This would mean that Portage would stay with 2.6 as long as you
> >> have something that doesn't work with 3.x installed.
> >
> > How do you detect this?
>
> By looking at the dependency graph?

But you can't tell whether everything will work with the new slot until
you've generated a full set of decisions, and you can't generate a full
set of decisions until you decide whether you want to install the newer
slot.

The problem with expecting the resolver to be clever is that the same
kind of clever in different places leads to horrible screwups... Every
time the resolver has to make some kind of decision that isn't utterly
explicit it's going to do the wrong thing in an annoying minority of
cases. Much better to just have ebuilds say exactly what they mean.

-- 
Ciaran McCreesh