ansible-lint 4.0.0 does not support py35 or py34

[ssbarnea]

Issue Type

• Bug report

Ansible and Ansible Lint details

ansible --version
ansible-lint --version

• ansible installation method: one of source, pip, OS package
• ansible-lint installation method: one of source, pip, OS package

Desired Behaviour

ansible-lint should run with any Python version that is currently used on production systems, especially on the Red Hat distributions.

Today I had a big surprise to see that installation failed because current python was py35. CentOS 7 has an optional python34 and python35, python34 being the default python3 interpreter! (installable via epel repository).

Actual Behaviour (Bug report only)

ansible-lint requires Python '>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*' but the running Python is 3.5.2

Example: http://logs.openstack.org/45/627545/1/check/openstack-tox-linters/e290e9d/job-output.txt.gz

So as long CentOS 7 and RHEL 7 are under normal or extended support, ansible-lint should keep compatibility with them, which should not be a big deal.

[SimonHeimberg]

Support for 3.4 and 3.5 was removed in 03e3f19#diff-380c6a8ebbbce17d55d50ef17d3cf906R64
Maybe this was planned, but I see nothing about this in the release notes.

[awcrosby]

The supported versions of ansible allow python35 so ansible-lint should allow that. We don’t test ansible-lint with python34 since ansible doesn’t support it, but we could still allow ansible-lint to be installed. PR #452 allows ansible-lint installation with python35 and python34. It also adds tox testing for python35. @webknjaz any issues with adding this back in? We can do a bug fix release by the end of the week.

[webknjaz]

It's a linting tool. I think there's no reason to make it compatible with all kinds of weird setups, it's supposed to run in CIs after all, which are usually more flexible in terms of what envs one can bring there.

I've set this spec based on envs declared in various configs as tested. Other envs were never supported.
See:

ansible-lint/tox.ini

Line 3 in f92cc06

envlist = py27-ansible{19,20,21},py{27,36}-ansible{22,23,24,25,devel},py{27,36}-flake8

&

ansible-lint/.travis.yml

Lines 49 to 71 in f92cc06

	- language: python
	python: "3.6"
	env: TOXENV=py36-ansible22
	- language: python
	python: "3.6"
	env: TOXENV=py36-ansible23
	- language: python
	python: "3.6"
	env: TOXENV=py36-ansible24
	- language: python
	python: "3.6"
	env: TOXENV=py36-ansible25
	- language: python
	python: "3.6"
	env: TOXENV=py36-ansibledevel
	- language: python
	python: "3.6"
	env: TOXENV=py36-flake8

Also, we do not run any testing against py34/py35. I think it would be misleading and wrong to mark something we don't test as supported.

Anyway, modern RHELs have Python 3.6+ available via Red Hat Software Collections: https://developers.redhat.com/blog/2018/08/13/install-python3-rhel/#how-to-use.

As for adding support, I think there shouldn't be anything blocking wrt syntax/features of python interpreters.

[awcrosby]

All good points. I will add py35 in our tox testing and allow it in the python_requires. I will hold off adding py34 since we cannot test with the supported ansible versions.