On Tuesday, September 13, 2011 06:46:33 Ciaran McCreesh wrote:
> On Tue, 13 Sep 2011 12:50:30 +0200 Michał Górny wrote:
> > > Are you sure this is defined behaviour? IUSE is a fancy merged
> > > variable for eclasses, and I don't think we guarantee that the value
> > > visible to the ebuild at any particular point is the generated value
> > > used by the package mangler.
> > 
> > True. I guess there's no way to tell whether a particular IUSE is
> > defined in the ebuild then? Hrm, I guess we'll need to break API
> > compat (and a number of ebuilds then) to get rid of this.
> 
> You don't do it by checking IUSE. You do it by having the ebuild define
> a variable like WANT_MONKEY_SUPPORT.

it's a crap shoot.  as long as Michał's proposed func doesnt attempt to make 
guarantees that don't exist now, i think it's fine.  we have ebuilds/eclasses 
that are already using it, so unifying it purely for the [+-] cleanup makes 
sense to me.
-mike