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 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))

                        c.update_msg = _('The following additional changes are available on %s:') % c.cs_branch_name

                    else:

                        show = set()

                        avail_revs = set() # drop revs[0]

                        c.update_msg = _('No additional changesets found for iterating on this pull request.')

                    # 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):

            c.limited_diff = True

        c.files = []

        c.changes = {}

        c.lines_added = 0

        c.lines_deleted = 0

        for f in _parsed:

            st = f['stats']

            c.lines_added += st['added']

            c.lines_deleted += st['deleted']

            fid = h.FID('', f['filename'])

            c.files.append([fid, f['operation'], f['filename'], f['stats']])

            htmldiff = diff_processor.as_html(enable_comments=True,

                                              parsed_lines=[f])

            c.changes[fid] = [f['operation'], f['filename'], htmldiff]

        # inline comments

        c.inline_cnt = 0

        c.inline_comments = cc_model.get_inline_comments(

                                c.db_repo.repo_id,

                                pull_request=pull_request_id)

        # count inline comments

        for __, lines in c.inline_comments:

            for comments in lines.values():

                c.inline_cnt += len(comments)

        # comments

        c.comments = cc_model.get_comments(c.db_repo.repo_id,

                                           pull_request=pull_request_id)

        # (badly named) pull-request status calculation based on reviewer votes

        (c.pull_request_reviewers,

         c.pull_request_pending_reviewers,

         c.current_voting_result,

         ) = cs_model.calculate_pull_request_result(c.pull_request)

        c.changeset_statuses = ChangesetStatus.STATUSES

        c.as_form = False

        c.ancestor = None # there is one - but right here we don't know which

        return render('/pullrequests/pullrequest_show.html')

    @LoginRequired()

    @NotAnonymous()

    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',

                                   'repository.admin')

    @jsonify

    def comment(self, repo_name, pull_request_id):

        pull_request = PullRequest.get_or_404(pull_request_id)

        status = request.POST.get('changeset_status')

        close_pr = request.POST.get('save_close')

        delete = request.POST.get('save_delete')

        f_path = request.POST.get('f_path')

        line_no = request.POST.get('line')

        if (status or close_pr or delete) and (f_path or line_no):

            # status votes and closing is only possible in general comments

            raise HTTPBadRequest()

        allowed_to_change_status = self._get_is_allowed_change_status(pull_request)

        if not allowed_to_change_status:

            if status or close_pr:

                h.flash(_('No permission to change pull request status'), 'error')

                raise HTTPForbidden()

        if delete == "delete":

            if (pull_request.owner.user_id == c.authuser.user_id or

                h.HasPermissionAny('hg.admin')() or

                h.HasRepoPermissionAny('repository.admin')(pull_request.org_repo.repo_name) or

                h.HasRepoPermissionAny('repository.admin')(pull_request.other_repo.repo_name)

                ) and not pull_request.is_closed():

                PullRequestModel().delete(pull_request)

                Session().commit()

                h.flash(_('Successfully deleted pull request %s') % pull_request_id,

                        category='success')

                return {

                   'location': url('my_pullrequests'), # or repo pr list?

                }

                raise HTTPFound(location=url('my_pullrequests')) # or repo pr list?

            raise HTTPForbidden()

        text = request.POST.get('text', '').strip()

        comment = create_comment(

            text,

            status,

            pull_request_id=pull_request_id,

            f_path=f_path,

            line_no=line_no,

            closing_pr=close_pr,

        )

        action_logger(self.authuser,

                      'user_commented_pull_request:%s' % pull_request_id,

                      c.db_repo, self.ip_addr, self.sa)

        if status:

            ChangesetStatusModel().set_status(

                c.db_repo.repo_id,

                status,

                c.authuser.user_id,

                comment,

                pull_request=pull_request_id

            )

        if close_pr:

            PullRequestModel().close_pull_request(pull_request_id)

            action_logger(self.authuser,

                          'user_closed_pull_request:%s' % pull_request_id,

                          c.db_repo, self.ip_addr, self.sa)

        Session().commit()

        if not request.environ.get('HTTP_X_PARTIAL_XHR'):

            raise HTTPFound(location=pull_request.url())

        data = {

           'target_id': h.safeid(h.safe_unicode(request.POST.get('f_path'))),

        }

        if comment is not None:

            c.comment = comment

            data.update(comment.get_dict())

            data.update({'rendered_text':

                         render('changeset/changeset_comment_block.html')})

        return data

    @LoginRequired()

    @NotAnonymous()

    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',

                                   'repository.admin')

    @jsonify

    def delete_comment(self, repo_name, comment_id):

        co = ChangesetComment.get(comment_id)

        if co.pull_request.is_closed():

            #don't allow deleting comments on closed pull request

            raise HTTPForbidden()

        owner = co.author.user_id == c.authuser.user_id

        repo_admin = h.HasRepoPermissionAny('repository.admin')(c.repo_name)

        if h.HasPermissionAny('hg.admin')() or repo_admin or owner:

            ChangesetCommentsModel().delete(comment=co)

            Session().commit()

            return True

        else:

            raise HTTPForbidden()