[Twisted-Python] [RFC] Drop support for Python 3.5 sometime after May 2021?

[Amber Brown (hawkowl)]

I was considering proposing dropping it soon (I was thinking when we had 
3.8 support, that 3.6/3.7/3.8 is a reasonable compatibility matrix).

Why I think this is probably fine:

- Debian Stable (buster) has 3.7. oldstable (stretch) has 3.5.3, but I 
don't think we care about oldstable.
- Ubuntu 18.04 has Python 3.6. 16.04 has 3.5.1, which is a sucky, buggy 
version that people shouldn't use anyway. Plus, getting a modern Python 
on Ubuntu isn't shockingly hard (deadsnakes makes it trivial).
- CentOS and RHEL 6 and 7 have Software Collections which makes Python 
3.6+ readily available.
- Windows has 3.8 available in the Store.
- MacOS doesn't ship a Python 3, but homebrew/python.org offer 3.8 easily.
- For everyone else, there's always Docker.

So, I guess if we have 3.8 support, the next release can announce the 
dropping of 3.5, and then the release after that can be the final one 
with support.

- Amber

On 14/5/20 5:10 am, Craig Rodrigues wrote:
> I would like to propose that Twisted drop support for Python 3.5 one 
> year from now in 2021.
> 
> Reasons:
> 
> 1.  Python 3.5.9 will be the final release of Python 3.5, in November 
> 2019 ( https://www.python.org/dev/peps/pep-0478/ )
> 2.  Python 3.6.0 was released in December 2016 ( 
> https://www.python.org/dev/peps/pep-0494/ )
> 3.  PyPy 7.1.1  introduced Python 3.6 support in April 2019 ( 
> https://morepypy.blogspot.com/2019/04/pypy-711-bug-fix-release.html ).
>      PyPy 7.3.1 is the latest PyPy version ( 
> https://morepypy.blogspot.com/2020/04/pypy-731-released.html ).
> 
> 4.  Python 3.6 introduced support for variable annotations ( 
> https://www.python.org/dev/peps/pep-0526/ )
> 5.  Python 3.6 introduced new string interpolation (f-string) support ( 
> https://www.python.org/dev/peps/pep-0498/ )
> 6.  Python 3.6 introduced support for asynchronous generators ( 
> https://www.python.org/dev/peps/pep-0525/ ) and asynchronous 
> comprehensions ( https://www.python.org/dev/peps/pep-0530/ )
> 
> 
> 
> Based on item 2., Python 3.6.0 has been around for almost 4 years, which 
> is a reasonable amount of time.
> Based on item 3., PyPy supports Python 3.6.
> 
> It might be nice to take advantage of some of the language features 
> introduces in items 4-6.
> 
> I think dropping support one year from now in 2021, would give 
> sufficient notice, and be in line with
> the Twisted Compatibility Policy ( 
> https://twistedmatrix.com/documents/current/core/development/policy/compatibility-policy.html 
> ).
> 
> None of these items are critial, but I thought I would ask, to get 
> people's opinions.
> 
> --
> Craig
> 
> _______________________________________________
> Twisted-Python mailing list
> Twisted-Python at twistedmatrix.com
> https://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
>