[Django]-How do I override delete() on a model and have it still work with related deletes

I’m doing the same thing and noticed a nugget in the Django docs that you should think about.

Overriding predefined model methods

Overriding Delete
Note that the delete() method for an object is not necessarily called when deleting objects in bulk using a QuerySet. To ensure customized delete logic gets executed, you can use pre_delete and/or post_delete signals.

This means your snippet will not always do what you want. Using Signals is a better option for dealing with deletions.

I went with the following:

import shutil
from django.db.models.signals import pre_delete 
from django.dispatch import receiver

@receiver(pre_delete)
def delete_repo(sender, instance, **kwargs):
    if sender == Set:
        shutil.rmtree(instance.repo)

Using clear() prior to deleting, removes all objects from the related object set.

see django-following-relationships-backward

example:

group.link_set.clear() 
group.delete() 

This seems only be sense-full if one Widget is connected to one WidgetFile exactly. In that case you should use a OneToOneField

from On-to-one examples:

# Delete the restaurant; the waiter should also be removed
>>> r = Restaurant.objects.get(pk=1)
>>> r.delete()

Just to throw in a possible way around this problem: pre-delete signal. (Not in any way implying there’s no actual solution.)

It should look like described on the django site:

class Blog(models.Model):
    name = models.CharField(max_length=100)
    tagline = models.TextField()
    def save(self, *args, **kwargs):
        do_something()
        super(Blog, self).save(*args, **kwargs) # Call the "real" save() method.
        do_something_else()

http://docs.djangoproject.com/en/dev/topics/db/models/#overriding-predefined-model-methods

you forgot to pass some arguments

Is some_widget_instance and instance of Widget or of WidgetFile ? Because if it is an instance of Widget it won’t get your custom delete() function, which is in the WidgetFile class.

I refactored this answer from the top answer above

import shutil
from django.db.models.signals import pre_delete 
from django.dispatch import receiver


"""WidgetFile is the model for the widget files.
pre_delete means delete run this function before the object is deleted from database"""
@receiver(pre_delete, sender=WidgetFile)
def delete_preo(sender, instance, **kwargs):
    shutil.rmtree(instance.repo)

Override model methods
Django signals

From Django 1.9, if You would just define on_delete=models.CASCADE for field, it will remove all related objects on delete.