I'm having trouble getting flake8 v3's --enable-extensions feature to work the way I want it. It's possible that I'm misunderstanding how it's supposed to work.

I have a checker plugin that starts out like:

class ImportOrder: name = 'flufl-import-order' version = '0.2' off_by_default = True

def __init__(self, tree, filename): # ...

def run(self): # ...

and it registers itself via an entry point like so:

setup( # ... entry_points={ 'flake8.extensions': ['U4 = flufl.testhelpers.imports:ImportOrder'], }, # ... )

All of the plugin's errors are U40X and U41X codes.

What I'd like to be able to do is to tell users to add this to say their tox.ini file:

[flake8] enable-extensions = U4

and that would enable my extension. This doesn't seem to work though.

I know that the extension runs just fine if I don't include the off_by_default=True class attribute, but as soon as I add that, there doesn't seem to be a way to re-enable it. I don't want to have to tell users that the plugin always runs and that they have to suppress the U4 errors if they don't want it.

What am I doing wrong? Or can I not do what I think I want to do? ;)

Cheers, -Barry