if org_repo.scm_instance.alias != other_repo.scm_instance.alias:

            msg = 'compare of two different kind of remote repos not available'

            log.error(msg)

            h.flash(msg, category='error')

            return redirect(url('compare_home', repo_name=c.repo_name))

        c.org_rev = self.__get_rev_or_redirect(ref=org_ref, repo=org_repo, partial=partial)

        c.other_rev = self.__get_rev_or_redirect(ref=other_ref, repo=other_repo, partial=partial)

        c.compare_home = False

        c.org_repo = org_repo

        c.other_repo = other_repo

        c.org_ref_name = org_ref_name

        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,

            other_repo.scm_instance, c.other_rev, merge)

        c.statuses = c.db_repo.statuses(

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

        if partial:

            return render('compare/compare_cs.html')

        if c.ancestor:

            assert merge

            # 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

            org_repo = other_repo

        else: # comparing tips, not necessarily linearly related

            rev1 = c.org_rev

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

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

                  % (rev1, c.other_rev, org_repo.scm_instance.path))

        txtdiff = org_repo.scm_instance.get_diff(rev1=rev1, rev2=c.other_rev)

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

                                             diff_limit=diff_limit)

        _parsed = diff_processor.prepare()

        c.limited_diff = False

        if isinstance(_parsed, LimitedDiffContainer):

            c.limited_diff = True

        c.files = []

        c.changes = {}

        c.lines_added = 0

        c.lines_deleted = 0

        for f in _parsed:

            st = f['stats']

            if not st['binary']:

                c.lines_added += st['added']