Re: [python-committers] Python 4.0 or Python 3.10?

On Tue, Sep 25, 2018 at 6:33 PM Victor Stinner <vstinner@redhat.com> wrote:

Hi,

I would prefer to never ever break the backward compatibility in Python. To make it clear I suggest to use 4.0 for the release following Python 3.7.

I think Serhiy made a strong argument that the code like below would break if we release Python 4.0:

 PY3 = sys.version_info[0] == 3
 if not PY3:
     ... # implies Python 2

I think we all have seen code like that; it's a common pattern. So by just bumping the version to 4.0 you would break the compatibility for some libraries and frameworks. And maybe breaking it is fine if there's a very strong technical reason, but doing that just to make a statement isn't worth it, IMHO.

Yury