buildbot broken by pylint upgrade

[ian-ross]

Issue description

Following this commit to upgrade pylint, buildbot no longer builds -- it uses Python 2.7, depends on pylint, and the latest pylint has disabled = pythonOlder "3.4".

Steps to reproduce

Try to install the buildbot package.

Technical details

• system: "x86_64-linux"
• host os: Linux 4.18.5-arch1-1-ARCH, Arch Linux, noversion
• multi-user?: no
• sandbox: no
• version: nix-env (Nix) 2.0.4
• channels(iross): "nixpkgs-18.09pre149415.8395f9aa85e"
• nixpkgs: /home/iross/.nix-defexpr/channels/nixpkgs

[vcunat]

/cc @dotlambda, @FRidh.

[dotlambda]

It seems like it's time to move buildbot to python3: #45789.

[ian-ross]

Wow. That was an awesomely quick response. Thanks, @dotlambda!

[lopsided98]

Pylint 1.8/1.9 is still maintained until 2020, so that is an alternative to maintain Python 2 support.

[vcunat]

Regardless, I wouldn't delay migration to python3 as the default without a good reason, even if the official un-supporting is still a bit over a year away.

[lopsided98]

Moving exclusively to Python 3 has the potential to break configurations, because they are written in Python. This might be fine, but we should be aware of it. See #45789 for more of this discussion.

[dotlambda]

I think we should provide indeed provide pylint 1.9 as python2Packages.pylint until support ends. I also think we should move buildbot to pythonPackages as @FRidh suggested.
@lopsided98 Do you want to continue my work?

[FRidh]

Please discuss ideas/plans and such on the issue (#45789), not the PR.

[lopsided98]

#45890 was merged a while ago, so this issue is resolved