[code-quality] Searching multiple setup.cfg files for flake8 section?

[Willy Wu]

Hey Ian, answers inline:

On Tue, Jul 7, 2015 at 4:36 PM, Ian Cordasco <graffatcolmingov at gmail.com>
wrote:

> Hey Willy,
>
> Responses in-line:
>
> On Tue, Jul 7, 2015 at 4:05 AM, Willy Wu via code-quality
> <code-quality at python.org> wrote:
> > Hey all,
> >
> > We use flake8 at Dropbox and are pretty happy with it.  But one small
> issue
> > is the way that flake8 configuration gets discovered.  We use the
> > per-project configuration via setup.cfg files which are checked into
> source
> > control, but flake8 only considers the first setup.cfg in the directory
> path
> > (regardless of whether it contains a flake8 section or not).  This
> forces us
> > to duplicate our [flake8] configuration across all of our various
> > setup.cfgs.
> >
> > Said in crude ascii form, this is a simplified version of our project
> > layout:
> > - repo root
> >   |- setup.cfg (default values)
> >   \- subservice #1
> >     \- setup.cfg (which has non-flake8 overrides for subservice #1)
> >   \- subservice #2
> >     \- setup.cfg (which similarly contains non-flake8 overrides for
> > subservice #2)
>
> So... to be clear... you're putting all of your Flake8 configuration
> in "repo root/setup.cfg" but you have other setup.cfg files in
> sub-directories. How are you running Flake8 (or perhaps, where are you
> running Flake8) such that it picks up the setup.cfg files in the
> sub-directories? Am I correct in assuming that you are running it in
> that sub-directory? If not, can you give me the command-invocation
> that triggers this?


Flake8 actually gets run automatically by our lint tools during code diffs,
but ultimately the command that runs is:
$ flake8 /Users/name/{repo_root}/{path_to_file}

But the current working directory during the command that kicks off flake8
is {repo_root}, so I was hoping that flake8 would search anywhere between
the file's directory and the current working directory when trying to
discover various setup.cfgs to consider.

I think the source of our confusion is that we use py.test as our unit test
runner, and they only consider setup.cfg a match if it contains a [pytest]
section, so there's kind of a tension between how you guys and pytest are
resolving configs.

Let me know what else you need?


>
> > But before I go off trying to patch flake8 code, is there relevant
> > background on why you guys don't try to discover the first setup.cfg
> with a
> > flake8 section, but instead just consider the first encountered
> setup.cfg?
> > We've seen teams accidentally break flake8 checking whenever they add
> > setup.cfg files for non-flake8 projects, and the "fix" is to copy/paste
> the
> > flake8 section into those new files.
>
> The easiest answer is simplicity. Flake8 piggy-backs off of pep8 when
> it comes to finding config files and consuming them.
>
> I think there were a couple of people who had requested that we search
> through all parent directories until we could find no parent directory
> to search for configuration files, but I hope you can understand why
> that is not feasible in the slightest. I believe the two places we
> search by default are:
>
> - Current working directory
> - User's home directory
>
> Traversing sub-directories is a little bit less offensive, but still
> not optimal. There is the option to specify the config file
> explicitly, but that doesn't help our users that much unless they have
> some (honestly bizarre) setup where they're using something like
> autoenv + shell aliases for flake8, e.g., autoenv could pick up the
> right config file path when changing into a directory and `flake8` is
> aliased to `/path/to/flake8 --config=$ENVVARWITHPATH`
>
> That's definitely a bit over-the-top and not exactly user-friendly.
>
> > Or alternatively, should we be doing something different with our project
> > layout as a workaround?  It's entirely possible that we should be
> > configuring things differently overall...?
>
> That's tough to say honestly. I don't really feel like it's my place
> (or anyone else's place) to tell you how to structure your project
> layouts. That decision should be 100% in your court.
>
> I'd still like to know a bit more about exactly how you're invoking
> flake8 in this case. I don't have a clear enough understanding of the
> problem to really be very helpful.
>
> Cheers,
> Ian
>
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