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 not c.cs_ranges:

                c.update_msg = _('Error: changesets not found when displaying pull request from %s.') % c.cs_rev

            elif 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:

                        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):

                    c.update_msg = _('This pull request has already been merged to %s.') % c.a_branch_name

                elif c.pull_request.is_closed():

                    c.update_msg = _('This pull request has been closed and can not be updated.')

                else: # look for descendants of PR head on source branch in org repo

                    avail_revs = org_scm_instance._repo.revs('%s:: & branch(%s)',

                                                             revs[0], c.cs_branch_name)

                    if len(avail_revs) > 1: # more than just revs[0]

                        # also show changesets that not are descendants but would be merged in

                        targethead = other_scm_instance.get_changeset(c.a_branch_name).raw_id

                        if org_scm_instance.path != other_scm_instance.path:

                            # Note: org_scm_instance.path must come first so all

                            # valid revision numbers are 100% org_scm compatible

                            # - both for avail_revs and for revset results

                            hgrepo = unionrepo.unionrepository(org_scm_instance.baseui,

                                                               org_scm_instance.path,

                                                               other_scm_instance.path)

                        else:

                            hgrepo = org_scm_instance._repo

                        show = set(hgrepo.revs('::%ld & !::parents(%s) & !::%s',

                                               avail_revs, revs[0], targethead))

                    else:

                        show = set()

                        avail_revs = set() # drop revs[0]

                    # TODO: handle branch heads that not are tip-most

                    brevs = org_scm_instance._repo.revs('%s - %ld - %s', c.cs_branch_name, avail_revs, revs[0])

                    if brevs:

                        # 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.update_msg = _('Error: some changesets not found when displaying pull request from %s.') % c.cs_rev

        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

        c.context_url = _context_url

        c.fulldiff = request.GET.get('fulldiff')

        diff_limit = self.cut_off_limit if not c.fulldiff else None

        # we swap org/other ref since we run a simple diff on one repo

        log.debug('running diff between %s and %s in %s',

                  c.a_rev, c.cs_rev, org_scm_instance.path)

        try:

            txtdiff = org_scm_instance.get_diff(rev1=safe_str(c.a_rev), rev2=safe_str(c.cs_rev),

                                                ignore_whitespace=ignore_whitespace,

                                                context=line_context)

        except ChangesetDoesNotExistError:

            txtdiff =  _("The diff can't be shown - the PR revisions could not be found.")

        diff_processor = diffs.DiffProcessor(txtdiff or '', format='gitdiff',

                                             diff_limit=diff_limit)

        _parsed = diff_processor.prepare()

        c.limited_diff = False

        if isinstance(_parsed, LimitedDiffContainer):

               <div id="owner_completion_container"></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}">

                      %if c.cs_ranges and cs.revision == c.cs_ranges[-1].revision:

                        <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>

                        <td style="width: 120px"><span class="tooltip" title="${h.age(cs.date)}">${cs.date}</span></td>

                        <td>${h.link_to(h.show_id(cs),h.url('changeset_home',repo_name=c.cs_repo.repo_name,revision=cs.raw_id), class_='changeset_hash')}</td>

                        <td>

                          <div style="float: right; margin-top: -4px;">

                            %for tag in cs.tags:

                              <div class="tagtag" title="${_('Tag %s') % tag}">

                                ${h.link_to(tag,h.url('changeset_home',repo_name=c.repo_name,revision=cs.raw_id))}

                              </div>

                            %endfor

                          </div>

                          <div class="message" style="white-space:normal; height:1.1em; max-width: 500px; padding:0">${h.urlify_commit(cs.message, c.repo_name)}</div>

                        </td>

                      %endif

                    </tr>

                  %endfor

                </table>

              </div>

              %endif

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

            </div>

        </div>

      </div>

    </div>

    ## REVIEWERS

    <div style="float:left; border-left:1px dashed #eee">

        <div class="pr-details-title">${_('Pull Request Reviewers')}</div>

        <div id="reviewers" style="padding:0px 0px 5px 10px">

          ## members goes here !

          <div>

            <ul id="review_members">

            %for member,status in c.pull_request_reviewers:

              ## WARNING: the HTML below is duplicate with

              ## kallithea/public/js/base.js

              ## If you change something here it should be reflected in the template too.

              <li id="reviewer_${member.user_id}">

                <div class="reviewers_member">

                    <div class="reviewer_status tooltip" title="${h.changeset_status_lbl(status)}">

                      <i class="icon-circle changeset-status-${status}"></i>

                    </div>

                  ${h.gravatar_div(member.email, size=14, div_class="reviewer_gravatar gravatar")}

                  <div style="float:left;">

                    ${member.full_name_and_username}

                    %if c.pull_request.user_id == member.user_id:

                      (${_('Owner')})

                    %endif

                  </div>

                  <input type="hidden" value="${member.user_id}" name="review_members" />

                  %if editable:

                  <div class="reviewer_member_remove action_button" onclick="removeReviewMember(${member.user_id})" title="${_('Remove reviewer')}">

                      <i class="icon-minus-circled"></i>

                  </div>

                  %endif

                </div>

              </li>

            %endfor

            </ul>

          </div>

          %if editable:

          <div class='ac'>

            <div class="reviewer_ac">

               ${h.text('user', class_='yui-ac-input',placeholder=_('Type name of reviewer to add'))}

               <div id="reviewers_container"></div>

            </div>

          </div>

          %endif