[gentoo-dev] Re: [RFC] PROPERTIES=set for meta-packages that should behave like package sets

[Steve Long <slong@rathaus.eclipse.co.uk>]

Ryan Hill wrote:

> Zac Medico <zmedico@gentoo.org> wrote:
>> Ryan Hill wrote:
>> > Though I'm still not sure what happens when a package is in two
>> > unrelated sets..
>> > 
>> > @gnome:
>> >    RDEPEND=">=gnome-extra/gnome-screensaver-2.22.2"
>> > 
>> > @xfce4:
>> >    RDEPEND="gnome-extra/gnome-screensaver"
>> > 
>> > package.use:
>> > @gnome             opengl
>> > @xfce              -opengl
>> 
>> I suppose we could use the order that they are listed in package.use
>> to apply the incremental stacking, so opengl would be disabled since
>> @xfce comes after @gnome.
> 
> I guess I'll need to stop sorting my package.use then. :p
> 
> But yeah, I have no better idea.  If someone really needs to lock down
> a USE flag on a pkg they can put the pkg atom itself into p.use.
> 
Indeed, although a more natural approach might be to take whichever
dependency is more specific (in the case where the user hasn't otherwise
expressed a preference, and there is a conflict.) The more specific dep
implies a closer relationship (although a warning would be useful ofc.)

Another way to express preference or association might be useful too,
although a category heuristic would also aid automated decision-making (the
set is being considered, so I'm guessing we know, which packages are listed
in it; can easily query if not.) The fallback would be the simple position
in the list.

While this might sound like yet more special-casing it's the kind of thing
that delights users ime, since it means less for them to worry about, and
only runs in the case where the decision is not clear from the
configuration and the tree. IOW something to specify as a 'may' rather
than 'undefined.'

(I still feel the same about losing 'world' ofc *sniff* ;)