On Tue, Oct 27, 2009 at 11:37:38PM +0530, Nirbheek Chauhan wrote:
> On Tue, Oct 27, 2009 at 11:29 PM, William Hubbs <williamh@g.o> wrote:
> > I just tested this, and make.conf overrides iuse defaults. ??To verify
> > this for yourself, pick a package with an iuse default turning on a
> > flag, then turn off the flag in make.conf and check what would happen if
> > you emerged the package.
> >
> > package.use overrides for a single package, but make.conf overrides for
> > all of your system.
> >
> 
> This behaviour is controlled by the variable USE_ORDER. make.globals
> sets this to:
> 
> USE_ORDER="env:pkg:conf:defaults:pkginternal:env.d"
 
That is correct, and the documentation (man make.conf) gives a very
strong warning about changing this setting:

"Do not modify this value unless you are a developer and you know what you
are doing.  If you change this and something breaks, we will not help
you fix it."

I can't find the bug right now, but at one point I asked in a bug about
the possibility of switching the order of defaults and pkginternal on
the grounds that if a maintainer wants to disable a use flag for a
package that is enabled in the profile they can't because the profile
overrides the iuse defaults.  It was closed as wontfix because it has
been agreed that the profile's use flag settings should have a higher
priority than the ebuild's.  I'm cool with that, but that is also why I
think the use flags the profiles enable should be the bare essentials
for using that profile.

-- 
William Hubbs
gentoo accessibility team lead
williamh@g.o