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.

More and more data confirm me frequently that we already reached the critical mass to declare that the migration to Python 3 is done.

There was no Python 2.8, I suggest to skip 3.8. Ten years is enough between two major versions...

To be clear, I only propose to change the version number. Not break anything. Not remove anything. Any pending removal scheduled for 4.0 must be postponed, maybe to 4.1, maybe 4.2, maybe never.

Linux switched from 3.x to 4.x and didn't break anything. We can do the same.


Ok, some people like me want to break the backward compatibility. You have to fight against that and make sure that incompatible changes are limited and very small per release.

Please don't use the C API as any promise of anything. This project is highly experimental and don't iffer anaything except pain at this point ;-)


Le mardi 25 septembre 2018, Yury Selivanov <yselivanov.ml@gmail.com> a écrit :
> What's the current plan for what version of Python we release after 3.9?
> The reason I'm asking this is because I frequently need to refer to
> *that version* of Python in the documentation, especially when I'm
> deprecating APIs or behavior.  Right now I'm saying "Python 4.0"
> implying that 4.0 will be released right after 3.9.
> I've heard multiple opinions on this subject. One of them is that we
> should release 4.0 when we have a major new change, like removal of
> the GIL or introduction of a JIT compiler.  On the other hand, we have
> no estimate when we have such a change. We also don't want Python 4.0
> to be backwards incompatible with Python 3.0 (at least not at the
> scale of 2 vs 3).  So to me, it seems logical that we simply release
> Python 4.0 after Python 3.9.  After all, after 3.9 Python will be
> drastically different from 3.0 and from 2.7.  It sounds better. :)
> Finally, I'm not sure we need a new governance in place to make this
> decision or maybe we can make it now. That's why I'm posting this to
> python-committers to see if core devs already have a consensus on
> this.
> Yury
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