Dynamic model, reverse foreign key not working

Hello,

My problem is very rare so I'll try ad add as much useful detail as possible.

I am using python 3.5 and 3.6, Django 1.11.4

I am creating complex security related application and need to generate additional models based on other applications' models. In general, everything works fine, models are created, migrated without a problem. But there is single problem I totally failed to solve.

Let's say there is preexisting model Alpha of some other application and I dynamically create model Beta which references Alpha with ForeignKey. The problem is that Beta does not get reverse relation, so I can query for beta.alpha, but not for alpha.betas. I receive "django.core.exceptions.FieldError: Cannot resolve keyword 'betas' into field. Choices are: x, y, z"

Here is my code

    def _create_dynamic_model(self, model_label, fields, attributes=None, options=None):
        from django.db import models

        class Meta:
            pass

        setattr(Meta, 'app_label', '_talos')

        if options is not None:
            for key, value in options.items():
                setattr(Meta, key, value)

        attrs = {'__module__': '_talos', '_talos_dynamic': True, 'Meta': Meta}

        if attributes:
            attrs.update(attributes)

        if fields:
            attrs.update(fields)

        model = type(model_label, (models.Model,), attrs)

        return model

I call it like this (where self.model is referenced model class)

    def _create_object_permission_model(self):
        from django.db import models

        return self._create_dynamic_model(
            'o_{0}_{1}'.format(self.model._meta.app_config.label, self.model.__name__),
            fields={
                'role': models.ForeignKey(
                    'talos.Role',
                    related_name='+',
                    on_delete=models.CASCADE),
                'permission': models.ForeignKey(
                    'talos.ObjectPermission',
                    related_name='+',
                    on_delete=models.CASCADE),
                'target': models.ForeignKey(
                    self.model,
                    related_name='talos_permissions', # self.model does not receive reverse relation!
                    on_delete=models.CASCADE)
            },
            options={
                'unique_together': [('role', 'permission', 'target')],
                'index_together': [
                    ('target', 'permission', 'role'),
                    ('target', 'role', 'permission'),
                    ('role', 'target', 'permission')]
            })


I tried calling contribute_to_class and contribute_to_related_class methods manually, tried to call this code at different moments (My application ready method, class_prepared signal handler), with absolutely no luck.

I tried to read Django sources, and got that contribute_to_related_class is called from contribute_to_class with delay, but it did not help me realize what exactly I am doing wrong.

I am trying to use reverse relation from custom view and admin, so everything should be pretty much initialized already.

Roman

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