c.jsdata = json.dumps(graph_data(org_scm_instance, revs))

        c.is_range = False

        if c.a_ref_type == 'rev': # this looks like a free range where target is ancestor

            cs_a = org_scm_instance.get_changeset(c.a_rev)

            root_parents = c.cs_ranges[0].parents

            c.is_range = cs_a in root_parents

            #c.merge_root = len(root_parents) > 1 # a range starting with a merge might deserve a warning

        avail_revs = set()

        avail_show = []

        c.cs_branch_name = c.cs_ref_name

        other_scm_instance = c.a_repo.scm_instance

        c.update_msg = ""

        c.update_msg_other = ""

        try:

            if org_scm_instance.alias == 'hg' and c.a_ref_name != 'ancestor':

                if c.cs_ref_type != 'branch':

                    c.cs_branch_name = org_scm_instance.get_changeset(c.cs_ref_name).branch # use ref_type ?

                c.a_branch_name = c.a_ref_name

                if c.a_ref_type != 'branch':

                    try:

                        c.a_branch_name = other_scm_instance.get_changeset(c.a_ref_name).branch # use ref_type ?

                    except EmptyRepositoryError: