如何在我的 Django 模型中强制执行 inheritance？

Question

In my Django app, I have an abstract model called MyModel that has eg created_at and updated_at fields. I want all the models in my project to subclass MyModel rather than using django.db.models.Model directly.

We have several developers on our app, so I want to use some sort of linter or CI check to enforce that this happens. How can I do this?

Answer 1

As mentioned by Willem Van Onsem in their comment you can write your own checks using the System check framework .

Assuming we have the following models in an app named "checktest" with Parent being the model that all models should inherit from:

from django.db import models


class Parent(models.Model):
    class Meta:
        abstract = True


# This should raise an error
class Foo(models.Model):
    pass


# This should be fine
class Bar(Parent):
    pass

We'll write a check as follows in a file checktest/custom_checks.py , note that the list APPS_TO_TEST contains the names of the apps whose models should inherit from the parent class:

from django.apps import apps
from django.core.checks import Error, register, Tags
from .models import Parent

# List of apps that should inherit from Parent
APPS_TO_TEST = ["checktest"]


@register(Tags.models)
def model_must_inherit(app_configs, **kwargs):
    errors = []
    for app in APPS_TO_TEST:
        models = apps.get_app_config(app).get_models()
        for model in models:
            if not issubclass(model, Parent):
                errors.append(Error(
                    f"Model {model.__name__} does not inherit from Parent",
                    hint="Models must inherit from the Parent class",
                    obj=model,
                    id="checktest.E001"
                ))
    return errors

In the app configs ready method we'll import the above file so that the check will get run:

from django.apps import AppConfig


class ChecktestConfig(AppConfig):
    default_auto_field = 'django.db.models.BigAutoField'
    name = 'checktest'

    def ready(self) -> None:
        from . import custom_checks

Now whenever we run commands like runserver or migrate the checks will get implicitly run. In a CI environment you can explicitly run the checks using the check command.