except UserInvalidException as u:

            h.flash(_('Invalid reviewer "%s" specified') % u, category='error')

            raise HTTPBadRequest()

        except Exception:

            h.flash(_('Error occurred while creating pull request'),

                    category='error')

            log.error(traceback.format_exc())

            raise HTTPFound(location=url('pullrequest_home', repo_name=repo_name))

        raise HTTPFound(location=pull_request.url())

    def create_new_iteration(self, old_pull_request, new_rev, title, description, reviewer_ids):

        org_ref_type, org_ref_name, org_rev = old_pull_request.org_ref.split(':')

        new_org_rev = self._get_ref_rev(org_repo, 'rev', new_rev)

        other_ref_type, other_ref_name, other_rev = old_pull_request.other_ref.split(':') # other_rev is ancestor

        #assert other_ref_type == 'branch', other_ref_type # TODO: what if not?

        new_other_rev = self._get_ref_rev(other_repo, other_ref_type, other_ref_name)

        cs_ranges, _cs_ranges_not, ancestor_revs = CompareController._get_changesets(org_repo.scm_instance.alias,

            other_repo.scm_instance, new_other_rev, # org and other "swapped"

            org_repo.scm_instance, new_org_rev)

        ancestor_rev = msg = None

        if not cs_ranges:

            msg = _('Cannot create empty pull request update') # cannot happen!

        elif not ancestor_revs:

            msg = _('Cannot create pull request update - no common ancestor found') # cannot happen