GenericRelation always deletes the related objects when a model object is deleted

[Brandon]

Is there a reason why when using GenericRelation a behaviour like on_delete=models.CASCADE is forced?
I've looked at the code for GenericRelation and ​on_delete is forced to models.CASCADE but ​GenricRel forces it to DO_NOTHING anyway.

Either way on_delete seems to be totally ignored because the related objects are part of ​_meta.private_fields and are deleted anyway.

The only way I've found to avoid this is to create a custom queryset like this

class MyQuerySet(models.QuerySet):
    def delete():
        pass
    def _raw_delete():
        return 0

class MyModel(models.Model):
    content_type = models.ForeignKey(ContentType, on_delete=models.SET_NULL, null=True)
    object_id = models.PositiveIntegerField(null=True)
    content_object = GenericForeignKey('content_type', 'object_id')

    objects = models.Manager.from_queryset(MyQuerySet)()

    class Meta:
       base_manager_name = "objects"

[Sarah Boyce]

This is a bug and duplicate of #26722