log.error(traceback.format_exc())

            h.flash(safe_str(e), category='warning')

            if not partial:

                redirect(h.url('summary_home', repo_name=repo.repo_name))

            raise HTTPBadRequest()

        """

        Returns a list of changesets that can be merged from org_repo at org_rev

        to other_repo at other_rev ... and the ancestor that would be used for merge.

        :param org_repo: repo object, that is most likely the orginal repo we forked from

        :param org_rev: the revision we want our compare to be made

        :param other_repo: repo object, mostl likely the fork of org_repo. It hass

            all changesets that we need to obtain

        :param other_rev: revision we want out compare to be made on other_repo

        """

        ancestor = None

        if org_rev == other_rev:

            changesets = []

                ancestor = org_rev

        elif alias == 'hg':

            #case two independent repos

            if org_repo != other_repo:

                hgrepo = unionrepo.unionrepository(other_repo.baseui,

                # so rev numbers from hgrepo can be used in other_repo

            #no remote compare do it on the same repository

            else:

                hgrepo = other_repo._repo

                if ancestors:

                    # pick arbitrary ancestor - but there is usually only one

                    ancestor = hgrepo[ancestors[0]].hex()

                # TODO: have both + and - changesets

            changesets = [other_repo.get_changeset(rev) for rev in revs]

        elif alias == 'git':

            if org_repo != other_repo:

                from dulwich.repo import Repo

        c.other_ref_name = other_ref_name

        c.org_ref_type = org_ref_type

        c.other_ref_type = other_ref_type

        c.cs_ranges, c.ancestor = self._get_changesets(

            org_repo.scm_instance.alias, org_repo.scm_instance, c.org_rev,

        c.statuses = c.db_repo.statuses(

            [x.raw_id for x in c.cs_ranges])

        if partial:

            return render('compare/compare_cs.html')

            # case we want a simple diff without incoming changesets,

            # previewing what will be merged.

            # Make the diff on the other repo (which is known to have other_rev)

            log.debug('Using ancestor %s as rev1 instead of %s'

                      % (c.ancestor, c.org_rev))

            rev1 = c.ancestor

            <i class="icon-resize-vertical" style="color:#DDD"></i>

        </td>

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

        </tr>

    %endfor

    </table>

    %if c.as_form:

      ${h.hidden('ancestor_rev',c.ancestor)}

      ${h.hidden('merge_rev',c.cs_ranges[-1].raw_id)}

    %endif

  %endif

</div>