related.py 文件源码

def _check_ignored_options(self, **kwargs):
        warnings = []

        if self.has_null_arg:
            warnings.append(
                checks.Warning(
                    'null has no effect on ManyToManyField.',
                    obj=self,
                    id='fields.W340',
                )
            )

        if len(self._validators) > 0:
            warnings.append(
                checks.Warning(
                    'ManyToManyField does not support validators.',
                    obj=self,
                    id='fields.W341',
                )
            )
        if (self.remote_field.limit_choices_to and self.remote_field.through and
                not self.remote_field.through._meta.auto_created):
            warnings.append(
                checks.Warning(
                    'limit_choices_to has no effect on ManyToManyField '
                    'with a through model.',
                    obj=self,
                    id='fields.W343',
                )
            )

        return warnings