[packagekit] exclude some upgrades

[David Zeuthen]

On Mon, 2007-11-12 at 15:17 -0500, Robin Norwood wrote:
> >>  - User tries to update system
> >>  - Transaction can't happen
> >>  - Some magic in the PacakgeKit yum backend to figure out the biggest
> >>    possible set that actually will make the transaction happen (hint:
> >>    look at a yum plugin that actually does this)
> >
> > Sure. Either we do this in the yum plugin or we handle this in the
> > yumBackend.py file.
> 
> Is this something that never happens in other distros/packaging systems?

Dependency hell is not exclusive to Fedora or RPM based distros.

> If so, then I can see why we might want to put the logic in the
> yum-specific parts.  Otherwise, if it's something than can be handled in
> an abstract way, why not put it in the engine so all backends can
> benefit?

I'd modify the interface of GetUpdates() [1] so instead of returning a
list of packages to be updated it returns two lists

 - list packages that can be updated:
   [
    git, 
    gnome-session, 
    rhythmbox
   ]

 - list of packages that are blocked and what packages are blocking 
   [
    [kernel, [kmod-nvidia, kmod-ntfs]],
    [hal-info, [hal]]
   ]

Here the update viewer would grey out the kernel and hal-info packages.

[1] : Sorry, I haven't studied the interfaces in detail so I'm making
this up. It may be just be noise.

     David