Re: [gentoo-dev] RFC: l10n.eclass

[Alexandre Rostovtsev]

On Fri, 2012-07-20 at 18:09 +0100, Ciaran McCreesh wrote:
> On Fri, 20 Jul 2012 12:39:21 -0400
> Mike Gilbert <floppym@g.o> wrote:
> > On Fri, Jul 20, 2012 at 2:54 AM, Ciaran McCreesh
> > <ciaran.mccreesh@××××××××××.com> wrote:
> > > On Thu, 19 Jul 2012 18:34:41 -0400
> > > Mike Gilbert <floppym@g.o> wrote:
> > >> On Thu, Jul 19, 2012 at 5:13 PM, Zac Medico <zmedico@g.o>
> > >> wrote:
> > >> > On 07/19/2012 06:14 AM, Ralph Sennhauser wrote:
> > >> >> Could be that Portage re-exports a sanitized
> > >> >> LINGUAS tough, but I doubt it.
> > >> >
> > >> > Portage does sanitize it if there are any linguas_* flags in
> > >> > IUSE, otherwise it lets the variable pass through without
> > >> > sanitizing it.
> > >>
> > >> That's good; we definitely don't want to "sanitize" it if there
> > >> are no linuguas_* flags in IUSE. This would break LINUGUAS support
> > >> for many autotools/gettext based packages, where the autotools
> > >> code parses LINGUAS directly and the ebuild does nothing with it.
> > >
> > > If there aren't any linguas_* flags in IUSE, LINGUAS should be
> > > empty, and will be in future EAPIs. Without that, USE dependencies
> > > on USE_EXPAND variables don't work.
> >
> > How do you figure that?
>
> If you dep upon foo[linguas_en(+)] and linguas_en isn't in IUSE, what
> happens?

Fatal error. If a package installs its translations implicitly via
gettext's rules depending on the value of LINGUAS at configure time,
then obviously other packages must rely on that package having installed
any particular translation.

> > The current portage behavior works well enough; if linugas_* is in
> > IUSE, LINGUAS is treated as a USE_EXPAND, and use-deps should work
> > fine.
> >
> > Otherwise, it is treated just like a normal environment variable, and
> > portage doesn't touch it.
>
> It's not a normal environment variable, and it never has been.

LINGUAS has been an environment variable with a special meaning for
gettext-based build systems, which are rather popular in the free
software world, since, oh, at least the year 2002 or so, when
gettext-0.11 was released. Maybe even earlier.

> > For most gettext packages, there is absolutely no reason that the
> > ebuild maintainer should have to keep track of every translation
> > available in a given package across version bumps. If you change this
> > behavior in a future EAPI, you will break this.
>
> Don't use a USE_EXPAND variable if you don't want USE_EXPAND behaviour.

Thousands of packages rely on a particular interpretation of LINGUAS
that has been standard across all distros for a decade. If that behavior
changed in EAPI5, then EAPI5 is not suitable for adoption in Gentoo.

-Alexandre.