ansible-lint: explicitly use python2Packages

[dotlambda]

The README tells us to use pip2. I infer that this package is not python3-compatible.
Also, the build fails when using python3Packages.

Motivation for this change

#18185

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Fits CONTRIBUTING.md.

---

cc @sengaya

[GrahamcOfBorg]

Success on aarch64-linux (full log)

Attempted: ansible-lint

Partial log (click to expand)

  /nix/store/lqr50cgvd0c9h2yiskzhldkr4kwmqb8s-python2.7-ansible-2.5.2
  /nix/store/mxppgv9z6g8m6bn0dcfyr4dwll9cjbwz-python2.7-paramiko-2.1.1
  /nix/store/wasxckwzal39ph216yv3nzjkbfk1892w-python2.7-dnspython-1.15.0
copying path '/nix/store/wasxckwzal39ph216yv3nzjkbfk1892w-python2.7-dnspython-1.15.0' from 'https://cache.nixos.org'...
copying path '/nix/store/j2bicmqm82z7y53piz8m17ahp9w3mfpj-python2.7-httplib2-0.11.3' from 'https://cache.nixos.org'...
copying path '/nix/store/d2q5z72bqv482vhzrwzg6fwb0qapv41h-python2.7-netaddr-0.7.19' from 'https://cache.nixos.org'...
copying path '/nix/store/mxppgv9z6g8m6bn0dcfyr4dwll9cjbwz-python2.7-paramiko-2.1.1' from 'https://cache.nixos.org'...
copying path '/nix/store/lqr50cgvd0c9h2yiskzhldkr4kwmqb8s-python2.7-ansible-2.5.2' from 'https://cache.nixos.org'...
copying path '/nix/store/55j0mjg2x6cpsdbqcxqfijdvh6xc800s-python2.7-ansible-lint-3.4.20' from 'https://cache.nixos.org'...
/nix/store/55j0mjg2x6cpsdbqcxqfijdvh6xc800s-python2.7-ansible-lint-3.4.20

[GrahamcOfBorg]

Success on x86_64-linux (full log)

Attempted: ansible-lint

Partial log (click to expand)

copying path '/nix/store/hxrc6lpr5a4d2z59wy9zj19hk34sv0gx-python2.7-dnspython-1.15.0' from 'https://cache.nixos.org'...
copying path '/nix/store/gywk7zbn93rl7xd01nlxjyv3srbw64i7-python2.7-httplib2-0.11.3' from 'https://cache.nixos.org'...
copying path '/nix/store/vdxkp10fl4jl7p6laijxs70ab2mgkxv8-python2.7-httpretty-0.8.10' from 'https://cache.nixos.org'...
copying path '/nix/store/49h73p7lqhy3ip4bwjqv1ixh1dd36hik-python2.7-netaddr-0.7.19' from 'https://cache.nixos.org'...
copying path '/nix/store/1kiwilkhqhbhgjadzgfvb7g0h0r6p2sv-python2.7-boto-2.47.0' from 'https://cache.nixos.org'...
copying path '/nix/store/iypqw2h964lkbiz260k0dn9lrnzqzyf5-python2.7-paramiko-2.1.1' from 'https://cache.nixos.org'...
copying path '/nix/store/md24qy8rykc737fnx876k9a9886dhi79-python2.7-pycrypto-3.6.4' from 'https://cache.nixos.org'...
copying path '/nix/store/61jk05bv9jhbcglx41g80g2f47zsabgi-python2.7-ansible-2.5.2' from 'https://cache.nixos.org'...
copying path '/nix/store/nm4vp6g24r2bcxbswmlc6n31mc3nf5br-python2.7-ansible-lint-3.4.20' from 'https://cache.nixos.org'...
/nix/store/nm4vp6g24r2bcxbswmlc6n31mc3nf5br-python2.7-ansible-lint-3.4.20

[Mic92]

Travis indicates it support both: https://github.com/willthames/ansible-lint/blob/master/.travis.yml

[dotlambda]

Okay, the problem is that ansible-lint must use the same python as ansible.
That means that anyway, we should override ansible in the ansible-lint expression. However, we should probably stick to python2 because ansible deliberately uses python2: #40277 (comment).
Also, it's kind of strange that ansible is in propagatedBuildInputs but not in pythonPackages. We should probably update the ansible expression to use buildPythonApplication and use toPythonModule in ansible-lint. What does @FRidh think?

[xeji]

Arch builds both ansible and ansible-lint with python3.

[dotlambda]

Arch builds both ansible and ansible-lint with python3.

Arch ships ansible 2.6, which has not even been released according to https://docs.ansible.com/ansible/latest/reference_appendices/release_and_maintenance.html#id13 but is nevertheless available on PyPI.
As mentioned in the PR linked to above, we ship 2.4 and 2.5 with 2.4 officially not supporting Python 3.

[xeji]

Ah right, forgot about that.

[sengaya]

I wonder if we can now that ansible 2.7 is released and 2.4 is out of support move fully to python3?

[Mic92]

@sengaya sounds like a plan

[Mic92]

replaced by #49764