[gentoo-dev] Always specify SLOT we know a package is compatible with (even if only one SLOT exists at the moment ebuild is added)

[Pacho Ramos]

Hello

With we trying to move to finally disable dymamic-deps and stop relying
on them completely, an old problem will be a bit more noticeable now:

- Tons of package RDEPEND on A
- Long time after that, A starts to have a new SLOT
- As most reverse deps need to be ported, we need to fix it
retroactively to request the old slot that is known to work.

Currently, we can see how most of us try to go as quick as possible to
fix the dependencies retroactively setting the proper slot but this
relies on dynamic-deps, if this feature gets disabled, we will need to
make revbumps for all of them and people will need to rebuild all the
reverse deps. This can be really problematic as some of this libs are
used by a ton of packages... I can think on recent examples like
gstreamer, gtk+, glib... for example a few days ago we needed to adapt
reverse deps to the inclusion of a new gtk-sharp slot.

On the other hand, if we start always setting the available slots that
we know to work, we can avoid this issue, and this is also completely
future proof becase I don't think we can assume that package B will
always work with the latest available SLOT package A can have in the
future. Then, applying the same policy of we trying to set the versions
in dependencies to the versions we know are compatible, we should do
the same with the slot.

Thanks a lot