Deleting recursion

[mvdwaeter]

When I delete a node that has children in the django-admin, I get a ForeignKey constrain IntegrityError, resulting in not deleting anything (using Postgres).

I think this is a flaw in the deleting sequence. What I think happens is this.
Take the Tree structure:

- Edition
-- Chapter
--- ContentPage
---- Module

• delete a Chapter
• this node has content-pages, hence remove these first
• when trying to remove the content-page, it can't because there are modules refering to it

I (temp) fixed it with a pre_save signal like so:

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

@receiver(pre_delete)
def pre_delete(sender, instance, using, **kwargs):

    if isinstance(instance, BaseTreeNode) and instance.can_have_children:
        for child in instance.children.all():
            child.delete()

This is my BaseTreeNode Model:

class BaseTreeNode(PolymorphicMPTTModel):
    parent = PolymorphicTreeForeignKey('self', blank=True, null=True, related_name='children', verbose_name=_('parent'))

This is an example child:

class Edition(BaseTreeNode):
    pass

Is there a more elegant way?

[vfigueiro]

Had exact same issue. Thanks for the workaround @mvdwaeter