Hello, all.

PyPy is currently slotted in a way similar to other versions of Python.
However, versioning of PyPy doesn't really fit the way CPython is
versioned and the almost-per-version slotting seems unnecessary.

My idea is to switch to a single slot of PyPy starting with the next
version to enter gx86. That is, we would no longer have:

  PYTHON_COMPAT=( pypy{1_8,1_9,2_0} ... )

but instead:

  PYTHON_COMPAT=( pypy pypy3 )

Similarly, we'd either have dev-python/pypy with slots 2 and 3, or even
separate dev-python/pypy3 with slot 0.

We would also add := subslot deps to enforce package rebuilds on pypy
upgrade.

The existing slots could be kept alive as long as pypy2.0 is supported.


Rationale:

Multiple slots of PyPy are using the standard library from the same
slot of CPython. Considering that slotting mostly helps prevent
breakages on upgrade, I don't think we actually need to make more
guarantees about PyPy than about CPython.

Therefore, new versions of PyPy often cause less trouble than new
versions of CPython. Testing all packages and updating PYTHON_COMPAT
on each new release of PyPy seems like a overkill to me.

Then, with pypy3 around, the version number appending ends up really
nasty. Having just 'pypy' and 'pypy3' will simply be cleaner :).


What do you think?

-- 
Best regards,
Michał Górny