Re: [gentoo-dev] [pre-GLEP] Optional runtime dependencies via runtime-switchable USE flags

[Michał Górny]

On Tue, 25 Sep 2012 17:00:07 +0100
Ciaran McCreesh <ciaran.mccreesh@××××××××××.com> wrote:

> On Tue, 25 Sep 2012 12:43:00 -0300
> Alexis Ballier <aballier@g.o> wrote:
> > Could you please elaborate on what kind of problems may arise ? The
> > proposal seems pretty simple and sane to me: PM only has to switch the
> > useflags that are IUSE_RUNTIME in his installed packages db after
> > installing the deps and without triggering a rebuild of said package.
>
> a) How do we provide a good user interface for it? It took an awful lot
> of experimenting to get the exheres-0 suggestions user interface to be
> good, and it requires quite a bit more information from the package
> side than this proposal is providing. We want to avoid a REQUIRED_USE
> here...

Who is we? I believe REQUIRED_USE is one of the features which will be
available thanks to staying compatible with USE flags instead of
reinventing the wheel.

> b) How is consistency checking to be done? Related, what happens when a
> runtime switch introduces a dependency that then requires a non-runtime
> rebuild of the original package?

Then the package is rebuilt. Where's the problem? Handling of
REQUIRED_USE is not perfectly user friendly but it works.

> c) How do we deal with flag? ( cat/dep[foo] ) or flag? ( >=cat/dep-2.1 )
> cases where cat/dep[-foo] or =cat/dep-2.0 is installed and flag is off?
> From experience, quite a few places where you'd want to use suggestions
> will break if their suggested package is installed but doesn't meet
> version or use requirements.

Er, you mean how to deal with an optional dependency which is not
enabled at all?

-- 
Best regards,
Michał Górny