Conservative adjustment of assignments_list.py

assignments_list-conservative.py

    def assignments_list(self, persistent=None):
        '''List assignments for devices which are (or may be) attached to the
           vm.

        Devices may be attached persistently (so they are included in
        :file:`qubes.xml`) or not. Device can also be in :file:`qubes.xml`,
        but be temporarily detached.

        :param bool persistent: only include devices which are or are not
        attached persistently.
        '''

        try:
            devices = self._vm.fire_event('device-list-attached:' + self._bus,
                persistent=persistent)
        except Exception:  # pylint: disable=broad-except
            self._vm.log.exception('Failed to list {} devices'.format(
                self._bus))
            if persistent is True:
                # don't break app.save()
                return list(self._set)
            raise
        result = []
        for dev, options in devices:
            if dev in self._set and not persistent:
                continue  # skipped
            if dev in self._set: # and persistent
                # add and potentially update later
                # could be skipped, as it would be added later
                # result.append(self._set.get(dev))
                continue
            elif dev not in self._set and persistent:
                continue  # skipped
            else: # dev not in self._set and not persistent:
                # add final
                result.append(
                    DeviceAssignment(
                        backend_domain=dev.backend_domain,
                        ident=dev.ident, options=options,
                        bus=self._bus))
        if persistent is not False:
            result.extend(self._set)
        return result