related.py 文件源码

def _check_to_fields_exist(self):
        # Skip nonexistent models.
        if isinstance(self.remote_field.model, six.string_types):
            return []

        errors = []
        for to_field in self.to_fields:
            if to_field:
                try:
                    self.remote_field.model._meta.get_field(to_field)
                except exceptions.FieldDoesNotExist:
                    errors.append(
                        checks.Error(
                            "The to_field '%s' doesn't exist on the related "
                            "model '%s'."
                            % (to_field, self.remote_field.model._meta.label),
                            obj=self,
                            id='fields.E312',
                        )
                    )
        return errors