Retaining support for python 3.5

sde1000 / python-dali

Library for controlling DALI lighting systems

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Retaining support for python 3.5 #73

Closed sde1000 closed 4 years ago

sde1000 commented 4 years ago

Leaving this question here because the issue has just come up in the pull request for command sequences:

Is anyone still using this library on python-3.5?

f-strings were introduced in python-3.6 and I'm so used to them now it seems odd to have to work around their absence!

Is it now reasonable to drop support for python-3.5?

sde1000 commented 4 years ago

I notice that f-strings are already in use in the drivers package and nobody has complained...

hasseb commented 4 years ago

It should be mentioned somewhere, which version of Python is required. Also other dependencies would be nice to have listed somewhere. In my fork I have rather extensive install instructions. When I first tried sde1000/python-dali it was not very easy to get it work. At least on that time the default Python3 version installed did not support f-strings. It is not very easy to find out whats wrong if you don't know Python and f-strings.

rnixx commented 4 years ago

Generally I am not a big fan of "cutting edge" features. I was not aware about the use of f strings in python-dali, otherwise I probably complained. My production setup still uses an older version of python-dali. As rule of thumb I'd prefer backward compatibility as long as reasonable.

dgomes commented 4 years ago

I use a simple rule of thumb:

What does Debian stable use ? That's the version I support

Debian stable is by definition old...

sde1000 commented 4 years ago

Current Debian stable is "buster" which uses Python 3.7.

Other older distributions: Ubuntu 18.04 (supported until April 2023) uses Python 3.6. Ubuntu 16.04 (supported until April 2021) uses Python 3.5.

I agree with @hasseb that the versions of Python supported should be documented (probably in the README, it's the most obvious place).

So: is anyone still actually using Python 3.5 with python-dali?

rnixx commented 4 years ago

Debian stable is by definition old

Sure, but in terms of embedded system still brandnew :)

However, I'd support 3.5+ until there's a real reason not to do any more.

sde1000 commented 4 years ago

The main reasons to drop support for 3.5 from my point of view:

the asyncio API only became stable in 3.6 (although was significantly improved in 3.7 and some of the calls required in 3.6 are now deprecated as of 3.8) — the asyncio-based driver code won't run on 3.5. I will at some point want to add a test suite for this, which the CI server is going to try to run under 3.5 and fail...
f-strings :-)
type annotation syntax was introduced in 3.6 and may be useful to add to the test suite

Even if we decide to retain support for 3.5 for now, I want to have a schedule for removing it. Significant dates coming up:

13 September 2020, the 5th anniversary of the Python 3.5 release
23 December 2020, the 4th anniversary of the Python 3.6 release
April 2021, end of support for Ubuntu 16.04

sde1000 commented 4 years ago

Nobody has come out and said that they need to use future releases of python-dali with Python 3.5, so I plan to document that it is no longer supported, and remove it from the CI configuration.