[code-quality] PyLint and Travis

[Kay Hayen]

Hello Florian,

thanks for your reply.

> > How to approach that. Is there a way I could have enforced using 1.9.2
> > on the "master" branch for Travis (and probably "develop" too), and
> > use the latest greatest PyLint for "factory" only. Anyone know if that
> > is possible, somehow, anybody doing something like that? Or maybe
> > install a given version, but make it an error if that version is not
> > the most recent on only the factory branch, what are people doing in
> > this regard?
>
> You'd usually use requirements.txt files with exact version pinning -
> ideally not only for pylint, but for all your dependencies and tools, to
> ensure deterministic, reproducable results.
>
> Then you can use https://requires.io/ or https://pyup.io/ to get
> notifications (or pull requests) to periodically update the pinned
> versions.

That sounds very nice. But you wouldn't normally put pylint into
the standard requirements, would you, so you would have a dedicated,
separate requirement file for it, to use with these services?

Right now, I am using on inline copies of scons which are used on
platforms where apt-get install scons won't work. And I the same with
appdirs. So I have no need yet for such files.

I just added one with PyLint now, before I was doing this in the install
second of Travis: python -c 'import sys;exit(sys.version_info[:2] not
in ((2,6), (3,3), (3,6)))' || pip install pylint

I blacklisted 3.6 for an error message that was not reproducible
outside of Travis. Obviously that was with
no 2.x version of PyLint. With pip syntax this might be more easily
expressed and commented too. This is
what I am trying right now:

# PyLint wouldn't be installable on 2.6 and not work with 3.3
pylint == 1.9.2 ; python_version < '2.7'
pylint == 2.0.0 ; python_version >= '3.4'

That approach of externally having these checked, makes sense to me
however. And I will
use a "requirements.txt" for for optional requirements too now. Nuitka
will just happen to work
without them installed too. Getting those notifications and even PRs
seems fine by me.

Yours,
Kay