fields.py 文件源码

def _check_generic_foreign_key_existence(self):
        target = self.remote_field.model
        if isinstance(target, ModelBase):
            fields = target._meta.private_fields
            if any(self._is_matching_generic_foreign_key(field) for field in fields):
                return []
            else:
                return [
                    checks.Error(
                        "The GenericRelation defines a relation with the model "
                        "'%s.%s', but that model does not have a GenericForeignKey." % (
                            target._meta.app_label, target._meta.object_name
                        ),
                        obj=self,
                        id='contenttypes.E004',
                    )
                ]
        else:
            return []