[New Rule][Django] Verify that settings is correctly imported

[bastian-wattro]

I'd like to add a rule for Django projects. I'm not quite sure about where to add it (If backwards capability was not an issue, I would add it to DJ)

What it could do

Verify that settings is correctly imported from django.conf.

An unsafe fix could exist, as some code might depend on the side effects of importing the module (even though import side-effects are considered poor practice).

Why is this bad?

The Django Docs state that one should import settings from django.conf.
It is an object (not a module) that is safe to access. Importing settings directly from the project could trigger side-effects.
Also, django.conf.settings abstracts the concepts of default settings and site-specific settings; it presents a single interface. It also decouples the code that uses settings from the location of the settings.

Example

Incorrect:

from myproject import settings

Use instead:

from django.conf import settings

---

I'm looking forward to your feedback.

[q0w]

You can already do this with banned-api (no auto fix)

[bastian-wattro]

Nice.

Add this to your pyproject.toml and replace myproject with the name of your project.
drop tool.ruff. if you're using ruff.toml

[tool.ruff]
lint.select = [
   …
   "TID251", # tidy imports
]
…
[tool.ruff.lint.flake8-tidy-imports.banned-api]
"myproject.settings".msg = "See https://docs.djangoproject.com/en/dev/topics/settings/#using-settings-in-python-code. Use 'from django.conf import settings' instead."