Re: [gentoo-dev] On flags being in IUSE (and the prefix USE-flag in particular)

[Gregory M. Turner]

On 9/7/2012 10:32 AM, Fabian Groffen wrote:

> With the introduction of IMPLICIT_IUSE (scheduled for EAPI 5), a phrase
> has been added to PMS, that finally makes a statement on what's supposed
> to be in IUSE, and what not[2].  To me, this patch means that things like
> userland_BSD, elibc_glibc, etc. do *NOT* belong in IUSE of an
> ebuild/eclass (and hence should b removed).  'prefix', on the other
> hand, should be added to IUSE of those ebuilds/eclasses that use them.

What, exactly, is the difference -- the principle behind the "should"s 
above?  USE_EXPAND?  Probably more a problem of me being lazy than 
anything being wrong with it, but [2] reads like Greek to me.

> For EAPI 5 (assuming it contains IMPLICIT_IUSE) the base profile can be
> enriched with IMPLICIT_IUSE="prefix".
>
> For all currently Council approved EAPIs this means 'prefix' has to be
> added to IUSE.

I haven't looked into IMPLICIT_IUSE too carefully, but ... shouldn't 
this be... implicit?  Sorry, I'm being super lazy and not reading 
anything here.

> In case you wonder why this is a problem now, Portage/repoman has a rule
> that USE-flags that are masked in the profiles implicitly are defined.

Probably making a total ass of myself at this point but... could you 
define "defined"?  I'm guessing I'd understand how to get flags masked 
implicitly if I read the IMPLICIT_IUSE stuff?  Or do you mean "are 
defined implicitly" (in which case, again, I don't see why we'd need to 
make them explicit).

> [2] http://git.overlays.gentoo.org/gitweb/?p=proj/pms.git;a=commitdiff;h=d9040ab3482af5f790368bac5d053bf1cd760ba8;hp=f9f7729c047300e1924ad768a49c660e12c2f906

Apologies for these questions -- in my defense, being both lazy and 
ignorant puts me at a real disadvantage here :)

-gmt