c.a_repo = c.pull_request.other_repo

        (c.a_ref_type,

         c.a_ref_name,

         c.a_rev) = c.pull_request.other_ref.split(':') # other_rev is ancestor

        org_scm_instance = c.cs_repo.scm_instance # property with expensive cache invalidation check!!!

        c.cs_repo = c.cs_repo

        try:

            c.cs_ranges = [org_scm_instance.get_changeset(x)

                           for x in c.pull_request.revisions]

        except ChangesetDoesNotExistError:

            c.cs_ranges = []

        c.cs_ranges_org = None # not stored and not important and moving target - could be calculated ...

        revs = [ctx.revision for ctx in reversed(c.cs_ranges)]

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

        c.is_range = False

        try:

            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

        except ChangesetDoesNotExistError: # probably because c.a_rev not found

            pass

        except IndexError: # probably because c.cs_ranges is empty, probably because revisions are missing

            pass

        avail_revs = set()

        avail_show = []

        c.cs_branch_name = c.cs_ref_name

        c.a_branch_name = None

        other_scm_instance = c.a_repo.scm_instance

        c.update_msg = ""

        c.update_msg_other = ""

        try:

                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:

                        c.a_branch_name = 'null' # not a branch name ... but close enough

                # candidates: descendants of old head that are on the right branch

                #             and not are the old head itself ...

                #             and nothing at all if old head is a descendant of target ref name

                if not c.is_range and other_scm_instance._repo.revs('present(%s)::&%s', c.cs_ranges[-1].raw_id, c.a_branch_name):

                        # also show changesets that are on branch but neither ancestors nor descendants

                        show.update(org_scm_instance._repo.revs('::%ld - ::%ld - ::%s', brevs, avail_revs, c.a_branch_name))

                        show.add(revs[0]) # make sure graph shows this so we can see how they relate

                        c.update_msg_other = _('Note: Branch %s has another head: %s.') % (c.cs_branch_name,

                            h.short_id(org_scm_instance.get_changeset((max(brevs))).raw_id))

                    avail_show = sorted(show, reverse=True)

            elif org_scm_instance.alias == 'git':

                c.cs_repo.scm_instance.get_changeset(c.cs_rev) # check it exists - raise ChangesetDoesNotExistError if not

                c.update_msg = _("Git pull requests don't support iterating yet.")

        except ChangesetDoesNotExistError:

        c.avail_revs = avail_revs

        c.avail_cs = [org_scm_instance.get_changeset(r) for r in avail_show]

        c.avail_jsdata = json.dumps(graph_data(org_scm_instance, avail_show))

        raw_ids = [x.raw_id for x in c.cs_ranges]

        c.cs_comments = c.cs_repo.get_comments(raw_ids)

        c.statuses = c.cs_repo.statuses(raw_ids)

        ignore_whitespace = request.GET.get('ignorews') == '1'

        line_context = safe_int(request.GET.get('context'), 3)

        c.ignorews_url = _ignorews_url

              ${_("This is just a range of changesets and doesn't have a target or a real merge ancestor.")}

            %else:

              ${h.link_to_ref(c.pull_request.other_repo.repo_name, c.a_ref_type, c.a_ref_name)}

              ## we don't know other rev - c.a_rev is ancestor and not necessarily on other_name_branch branch

            %endif

          </div>

        </div>

        <div class="field">

          <div class="label-summary">

              <label>${_('Pull changes')}:</label>

          </div>

          <div class="input">

              <div>

               ## TODO: use cs_ranges[-1] or org_ref_parts[1] in both cases?

               %if h.is_hg(c.pull_request.org_repo):

                 <span style="font-family: monospace">hg pull ${c.pull_request.org_repo.clone_url()} -r ${h.short_id(c.cs_ranges[-1].raw_id)}</span>

               %elif h.is_git(c.pull_request.org_repo):

                 <span style="font-family: monospace">git pull ${c.pull_request.org_repo.clone_url()} ${c.pull_request.org_ref_parts[1]}</span>

               %endif

              </div>

          </div>

        </div>

        <div class="field">

          <div class="label-summary">

              <label>${_('Created on')}:</label>

          </div>

          <div class="input">

              <div>${h.fmt_date(c.pull_request.created_on)}</div>

          </div>

        </div>

        <div class="field">

          <div class="label-summary">

              <label>${_('Next iteration')}:</label>

            </div>

            <div class="input">

              <div class="msg-div">${c.update_msg}</div>

              %if c.avail_revs:

              <div id="updaterevs" style="max-height:200px; overflow-y:auto; overflow-x:hidden; margin-bottom: 10px; padding: 1px 0">

                <div style="height:0">

                  <canvas id="avail_graph_canvas" style="width:0"></canvas>

                </div>

                <table id="updaterevs-table" class="noborder" style="padding-left:50px">

                  %for cnt, cs in enumerate(c.avail_cs):

                    <tr id="chg_available_${cnt+1}">

                        <td>

                          %if editable:

                            ${h.radio(name='updaterev', value='', checked=True)}

                          %endif

                        </td>

                        <td colspan="4">${_("Current revision - no change")}</td>

                      %else:

                        <td>

                          %if editable and cs.revision in c.avail_revs:

                            ${h.radio(name='updaterev', value=cs.raw_id)}

                          %endif

                        </td>