Re: installing python 2 and python 3 in the same profile

[Konrad Hinsen <konrad.hinsen@fastmail.net>]

Ricardo Wurmus <rekado@elephly.net> writes:

> It is an unnecessary restriction to *prevent* users from installing
> Python 2 and 3 interpreters into the same profile.  Any errors we see

I agree. But the current question is not if we should allow people to
shoot themselves into the foot, but how much effort we should invest to
make this possible.


Pjotr Prins <pjotr.public12@thebird.nl> writes:

>> It is an unnecessary restriction to *prevent* users from installing
>> Python 2 and 3 interpreters into the same profile.  Any errors we see
>> with mixing 2 and 3 is due to a bug in Guix which is due to our use of
>> PYTHONPATH.
>
> Alright, if you choose to use them as two different tools/languages.

Which is what they are - the biggest mistake in the Python 2->3
transition was, in my opinion, to pretend they are the same language.
It is possible to write programs that are valid in both languages but
produce different results; this even happens regularly by mistake
due to the change of division semantics. So by my definition, they are
two similar but distinct languages.

> Sure. Note that Python2 is quickly becoming obsolete. It is escalating
> because packages are now dropping support. After 10 years of joy
> mixing versions...

I expect Python 2 to remain widely used for another 10 years after
official support ends. Applications that have no security concerns can
simply continue to build on the last official release of Python 2 and
its library ecosystem. For applications with a high migration cost, it's
still not worth the effort to port to Python 3.

Konrad.