Re: [gentoo-dev] Re: Reverse use of Python/Ruby versions

[James Potts <arek75@gmail.com>]

As another user, I have an interesting thought:  Keep *_TARGETS and
*_COMPAT, but add useflags called "[python|php|ruby]-compat-testing",
which is at least use.stable.mask'ed (possibly straight-up
use.mask'ed), to any ebuild that uses *_COMPAT.  Setting the
appropriate useflag would allow such ebuilds to build against any
interpreter version listed in the appropriate *_TARGETS variable, even
those the ebuild doesn't explicitly support.

To help with keeping things reasonable, support for both ranges and
negation could be added to *_COMPAT.  This way, for example, an ebuild
for a Python 2.7-only program, could specify PYTHON_COMPAT="2.7
->=3.0", and the ebuild for a ruby app that's known to be broken in
2.2 but works fine in both 2.1 and 2.3 could specify
RUBY_COMPAT="-2.2". Obviously, the *-compat-testing flags should not
allow building against a known-incompatible TARGET if this is
implemented. :)

This keeps the benefits of *_COMPAT and *_TARGETS while allowing
people to test a new python/php/ruby interpreter without having to
manually edit dozens (potentially hundreds or thousands) of ebuilds.

--James