Re: [gentoo-dev] [RFC] Forced/automatic USE flag constraints (codename: ENFORCED_USE)

[Michał Górny]

On śro, 2017-06-14 at 16:09 +0200, Alexis Ballier wrote:
> On Wed, 14 Jun 2017 15:57:38 +0200
> Michał Górny <mgorny@g.o> wrote:
> [...]
> > > [...]
> > > > > > > > [1]:https://wiki.gentoo.org/wiki/User:MGorny/GLEP:ReqUse
> > > > > > >
> > > > > > > I really don't like the reordering thing. Even the
> > > > > > > restricted syntax does not fix the issue with '^^ ( a b )
> > > > > > > b? ( a )' already mentioned here. It'd be much better and
> > > > > > > simpler for the spec just to assign a fixed value and use
> > > > > > > the solving rules with those.
> > > > > >
> > > > > > You're not going to convince me by providing examples that are
> > > > > > utterly broken by design and meaningless ;-).
> > > > >
> > > > > Well... if it's so obvious that the example is broken by design
> > > > > that you don't even bother to explain why, I assume you have an
> > > > > algorithm for that. Where is the code ? What are the numbers ?
> > > > > How many ebuilds might fail after reordering ? How can this be
> > > > > improved ?
> > > >
> > > > Are you arguing for the sake of arguing here? I just presumed that
> > > > this example is so obviously broken there is no point wasting any
> > > > more time on it. The code of nsolve clearly detects that, so I
> > > > don't really understand what you're trying to prove here.
> > >
> > > Those are real questions. You should take breath, think a bit about
> > > it, and try to run the 2 possible orderings of the ^^ through
> > > nsolve or even solve.py. They both are very happy (and are right to
> > > be) with the above ordering. You might want to think a bit more
> > > about what is the relation between this broken 10 chars example and
> > > the 10 lines python targets one below.
> > >
> > > You should also realize that all the above questions have already
> > > been answered in length if you do as I suggest.
> >
> > No. I have already spent too much time on this. We're already long
> > past all useful use cases, and now I feel like you're going to argue
> > to death just to find a perfect algorithm that supports every absurd
> > construct anyone can even write, if only to figure out the construct
> > is completely useless.
>
> I'm not going to argue to death. It's already proven reordering is
> broken.
>
> > If you want to play with it more, then please by all means do so.
>
> There is nothing to do for reordering. It's broken by design.
>
> > However, do not expect me to waste any more of my time on it. I've
> > done my part, the code works for all reasonable use cases and solves
> > all the problems I needed solving. If you want more, then it's your
> > job to do it and solve the resulting issues.
>
> Like... writing code handling all the cases and describing how it
> works ? We're past that. The only thing we're not past is that you fail
> to understand it and attempt to block it.
>

Then please provide a single valid example that:

a. is completely 'correct' (that is, provides a valid, predictable
and acceptable solution) with the default ordering O_a,

b. is not 'correct' with at least one reordering O_b (assuming only ||,
^^, ?? is subject to reordering),

c. nsolve reports O_a as all good, and O_b as not good.

The best way to convince me is through valid examples.

-- 
Best regards,
Michał Górny