Re: [gentoo-dev] useflag policies

[Andrew Savchenko]

On Sun, 2 Aug 2015 20:35:27 +0200 Michał Górny wrote:
> Dnia 2015-08-02, o godz. 21:21:03
> Andrew Savchenko <bircoph@g.o> napisał(a):
>
> > On Sun, 2 Aug 2015 19:27:02 +0200 Michał Górny wrote:
> > > Long story short, this is USE=gtk once again. GNOME team had a
> > > policy that handled the case cleanly and QA outvoted it in favor of
> > > Qt-like policy. Then Qt team figured out their policy was unfriendly,
> > > and 'fixed' it with this ugly hack...
> > >
> > > As I see it, this is a major failure of using toolkit-version oriented
> > > flags rather than feature-oriented flags. Possibilities compared:
> > >
> > > USE='qt4 qt5' without ^^ is easy to set since it is free of REQUIRED_USE
> > > issues. However, it's ugly: USE='qt4 qt5' may now mean either both
> > > toolkits or one of them. In the latter case, we have two flag
> > > combinations (= two different binary packages) that mean the same.
> > > Additionally, USE='-qt4 -qt5' may mean both none of them or one of
> > > them. If the latter, yet another case of redundant binary package.
> > >
> > > USE='qt4 qt5' with ^^/?? is cleaner from user perspective and better
> > > for binary packages. However, it may mean that user will have to
> > > randomly adjust flags per-package. Which may end up sucking even more
> > > with new Qt versions being introduced and package.use being full of
> > > random '-qt4' and stuff.
> > >
> > > What would be really clean is USE='qt qt5' (or 'qt qt4'), alike GNOME
> > > team policy. USE=qt would mean 'any version of Qt, if optional', and
> > > qt4/qt5 would be used to switch between Qt4/Qt5. If Qt would be
> > > obligatory, no USE=qt would apply. If only one Qt version would be
> > > supported, no USE=qt4/qt5 would apply. Clean, sane and limited
> > > package.use cruft.
> >
> > This is a clean solution for developers and maintainers, but not
> > for ordinary users — they will confused by "qt qt4 qt5": "what is
> > 'qt', how is it different from 'qt4' and 'qt5'.
>
> This can be easily fixed via USE flag descriptions. And unlike with
> your solution, the descriptions can be globally consistent.
>
> > What you are really
> > doing is implementing second-level USE flags, while they were
> > supposed to be linear.
>
> Please support such claims with references.

A reference from your previous e-mail:
> > On Sun, 2 Aug 2015 19:27:02 +0200 Michał Górny wrote:
[...]
> > > What would be really clean is USE='qt qt5' (or 'qt qt4'), alike GNOME
> > > team policy. USE=qt would mean 'any version of Qt, if optional', and
> > > qt4/qt5 would be used to switch between Qt4/Qt5. If Qt would be
> > > obligatory, no USE=qt would apply. If only one Qt version would be
> > > supported, no USE=qt4/qt5 would apply. Clean, sane and limited
> > > package.use cruft.

You're proposing "qt" as a top level USE flag, while "qt4/qt5" will
be in your opinion optional clarifying USE flags. This way we have
second-level hierarchy.

Best regards,
Andrew Savchenko