Re: [gentoo-portage-dev] Re: Dynamic USE dependencies

[Rich Freeman <rich0@gentoo.org>]

On Wed, Apr 8, 2015 at 3:45 AM, Martin Vaeth <martin@mvath.de> wrote:
> Rich Freeman <rich0@gentoo.org> wrote:
>>
>> Keep in mind that keeping track of past decisions made by portage does
>> not require user-editable config files in /etc.
>
> Yes, but you might not always agree with portage's decisions,
> and the resolution might be non-unique.

How is this different with USE flags vs package installs?  The
satisfaction of virtuals could have many possible solutions.  We make
it deterministic by defaulting to the first option listed for the
first package that happens to get installed.  If you install a series
of packages in various orders from a fresh install, you could get
different packages installed to satisfy virtuals.

The solution we provide for package installs is that the user can just
emerge a dependency manually if they have a preference, and then
portage will stick with it unless there is a conflict.

For dynamic USE flags I've already proposed two mechanisms to give the
user control:
1.  They can STILL populate /etc/portage/package.use and make explicit
choices, which portage will follow.
2.  They could manually install a package with one-time specified USE
flags, and portage would stick with these as long as they don't create
a conflict.

Why do we need another mechanism to control what flags a package gets
installed with other than these two, such as making more detailed
cache data user-editable?

-- 
Rich