On Saturday 10 of October 2009 22:50:37 Zac Medico wrote:
> Maybe a syntax extension for IUSE would be a little nicer. For example:
> 
>   IUSE="unstable? ( foo bar )"

No no no, the biggest reason for this is to not touch ebuild at all - it needs 
to be fully ebuild independent.

It's like with recent KDE4 stabilization. Having ability to exclude certain 
optional dependencies from stabilization *without* modifying ebuilds (remove 
USE flag and its support from IUSE) is the motivation here.
For now - we just mask them in package.use.mask with appropriate version 
specification (let's say <=kde-base/kdeutils-meta-4.3.10 cups) - but it's not 
ideal as you may think.

It's no surprise, we don't manage ebuilds in *purely* individual manner - 
instead we try to keep all ebuilds across all releases the same if possible 
(eclass handles it properly) - it's over 250 of them after all and we maintain 
now 4.3.1, 4.3.2, 4.3.9999 (stable branch - what makes next 4.3.x releases), 
9999 (pure trunk) and trunk snapshots like 4.3.69.

-- 
regards
MM