sopel: drop support for Python < 3.6

[Exirel]

Description

Fix #1801 and hopefully nothing else so @dgw can have a good time removing deprecated stuffs himself. 😁

Checklist

• I have read CONTRIBUTING.md
• I can and do license this contribution under the EFLv2
• No issues are reported by make qa (runs make quality and make test)
• I have tested the functionality of the things this change touches

[dgw]

This will have to drop CI for the older Pythons too. Not going to worry about it until 7.1 is done.

LGTM's new alerts are interesting. Annoying, but interesting. I thought we were importing division from the future to avoid such things.

[Exirel]

This will have to drop CI for the older Pythons too. Not going to worry about it until 7.1 is done.

There are many other things to do, yes. In this PR, I focused only on removing/adapting the code, but I tried not to touch anything that would be used by the CI or the githook stuff.

I thought we were importing division from the future to avoid such things.

Which is not necessary with Python 3 as the true division is now by default. I'm pretty sure it's because LGTM is configured with Py2.7.

Also, It's funny to see that the CI fails on Py2.7 to 3.5, and is fine for 3.6+—just as planned!

[dgw]

I tried not to touch anything that would be used by the CI or the githook stuff.

Also, It's funny to see that the CI fails on Py2.7 to 3.5, and is fine for 3.6+—just as planned!

Leaving the CI stuff, at least, means this PR can never pass checks. Passing CI is required to merge. Dropping support for a Python version should include removing tests for that version, because we shouldn't waste resources testing something unsupported.

And speaking of unsupported things, the githooks are contrib stuff, so it's fine not to worry about those. Doesn't look like @HumorBaby included anything Python-version-specific in those, though.

I'm pretty sure it's because LGTM is configured with Py2.7.

It's probably because we still have Python 2.7 in CI and/or requirements files. LGTM assumes Python 3 if it doesn't see any versions specified; see https://lgtm.com/help/lgtm/python-extraction#python_setup-step

[Exirel]

Yup yup, I agree with that. Which makes me realized that I should have opened that as a DRAFT and not a ready PR, my mistake!

My reasoning about CI stuff was to give you the code first, and see what needed to be done exactly for the CI—something I know too little about at the moment—and to do that with you. So yeah, absolutely, the CI need to be modified.

My guess is that you're probably too busy to look at that now, and I'm sure it's better to wait after 7.1 is released than right now.

[dgw]

Dropped back to draft status. You're correct, I'd rather spend my time on 7.1 stuff now, and tackle this after it's released. 😸

[dgw]

Surprisingly few line notes, considering the scope of this PR. Given that it's mostly deleting dead code and swapping imports, though, it's actually not that surprising after all.

Hopefully LGTM will figure out that we don't care about py2 any more now that CI and everything has been reworked to target only 3.6+, and stop giving irrelevant warnings.

[lgtm-com]

This pull request introduces 2 alerts and fixes 1 when merging cfba6d7 into 56d84d1 - view on LGTM.com

new alerts:

• 1 for 'input' function used in Python 2
• 1 for Result of integer division may be truncated

fixed alerts:

• 1 for Module is imported with 'import' and 'import from'

[dgw]

I'm baffled after studying LGTM's docs about Python version selection. It should default to Python 3, but isn't. Let's ignore the new alerts on this PR and look into it separately if they still appear on master after merging.

[half-duplex]

Depending on the scope of this PR...

• requirements.txt and dev-requirements.txt should have the python_version == '2.7' etc lines removed. This also "fixes" CVE-2021-33503 (DoS), which sopel 7 will remain vulnerable to.
• docs/source/configuration.rst has a comment about py2.7
• README.rst says "Sopel requires Python 2.7.x or Python 3.3+ to run", etc
• The shebang of sopel/cli/run.py specifically uses 2.7 (dear god, why? does this even need a shebang?)

To be done in future PR:

• sopel/formatting.py TODO
• conftest.py 2x "Python 3.3" comments
• sopel/plugins/rules.py has a 2.7 TODO
• sopel/irc/backends.py SSLAsynchatBackend.handle_connect

[Exirel]

Depending on the scope of this PR...

Indeed, more work to do! I've done what I could or think is important right now.

I left aside the TODOs in sopel.plugins (there are many!), as they will be dealt with in a future PR to rework/replace what was kept for older versions of Python.

[dgw]

Some more stuff, mostly about requirements. Very close!

[Exirel]

Here we go. I haven't rebased/squashed yet. Other than that, it's ready for final review: everything new should go in new PRs, I think.

[dgw]

Squash the fixups and let's ship it. "Don't sweat the little stuff," etc., there's plenty of time to catch the stragglers and handle the various TODOs.