old_revisions = set(old_pull_request.revisions)

        revisions = [cs.raw_id for cs in cs_ranges]

        new_revisions = [r for r in revisions if r not in old_revisions]

        lost = old_revisions.difference(revisions)

        infos = ['','', 'This is an update of %s "%s".' %

                 (h.canonical_url('pullrequest_show', repo_name=old_pull_request.other_repo.repo_name,

                      pull_request_id=pull_request_id),

                  old_pull_request.title)]

        if lost:

            infos.append(_('Missing changesets since the previous version:'))

            for r in old_pull_request.revisions:

                if r in lost:

                    desc = org_repo.get_changeset(r).message.split('\n')[0]

                    infos.append('  %s "%s"' % (h.short_id(r), desc))

        if new_revisions:

            infos.append(_('New changesets on %s %s since the previous version:') % (org_ref_type, org_ref_name))

            for r in reversed(revisions):

                if r in new_revisions:

                    desc = org_repo.get_changeset(r).message.split('\n')[0]

                    infos.append('  %s %s' % (h.short_id(r), h.shorter(desc, 80)))

            if ancestor_rev == other_rev:

                infos.append(_("Ancestor didn't change - show diff since previous version:"))

                infos.append(h.canonical_url('compare_url',

                                 repo_name=org_repo.repo_name, # other_repo is always same as repo_name

                                 org_ref_type='rev', org_ref_name=h.short_id(org_rev), # use old org_rev as base

                                 other_ref_type='rev', other_ref_name=h.short_id(new_org_rev),

                                 )) # note: linear diff, merge or not doesn't matter

            else:

                infos.append(_('This pull request is based on another %s revision and there is no simple diff.') % other_ref_name)

        else:

           infos.append(_('No changes found on %s %s since previous version.') % (org_ref_type, org_ref_name))

           # TODO: fail?

        # hack: ancestor_rev is not an other_ref but we want to show the

        # requested destination and have the exact ancestor

        new_other_ref = '%s:%s:%s' % (other_ref_type, other_ref_name, ancestor_rev)

        new_org_ref = '%s:%s:%s' % (org_ref_type, org_ref_name, new_org_rev)

        reviewers = [r.user_id for r in old_pull_request.reviewers]

        try:

            old_title, old_v = re.match(r'(.*)\(v(\d+)\)\s*$', old_pull_request.title).groups()

            v = int(old_v) + 1

        except (AttributeError, ValueError):

            old_title = old_pull_request.title

            v = 2

        title = '%s (v%s)' % (old_title.strip(), v)

        description = (old_pull_request.description.rstrip() +

                       '\n'.join(infos))

        try:

            pull_request = PullRequestModel().create(

                self.authuser.user_id,

                old_pull_request.org_repo.repo_name, new_org_ref,

                old_pull_request.other_repo.repo_name, new_other_ref,

                revisions, reviewers, title, description

            )

        except Exception:

            h.flash(_('Error occurred while creating pull request'),

                    category='error')

            log.error(traceback.format_exc())

            return redirect(old_pull_request.url())

        ChangesetCommentsModel().create(

            text=_('Closed, replaced by %s .') % h.canonical_url('pullrequest_show',

                                                   repo_name=old_pull_request.other_repo.repo_name,

                                                   pull_request_id=pull_request.pull_request_id),

            repo=old_pull_request.other_repo.repo_id,

            user=c.authuser.user_id,

            pull_request=pull_request_id,

            closing_pr=True)

        PullRequestModel().close_pull_request(pull_request_id)

        Session().commit()

        h.flash(_('Pull request update created'),

                category='success')

        return redirect(pull_request.url())

    # pullrequest_post for PR editing

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    def post(self, repo_name, pull_request_id):

        repo = RepoModel()._get_repo(repo_name)

        pull_request = PullRequest.get_or_404(pull_request_id)

        old_description = pull_request.description

        _form = PullRequestPostForm()().to_python(request.POST)

        pull_request.title = _form['pullrequest_title']

        pull_request.description = _form['pullrequest_desc'].strip() or _('No description')

        PullRequestModel().mention_from_description(pull_request, old_description)

        Session().commit()

        h.flash(_('Pull request updated'), category='success')

        return redirect(pull_request.url())

    # pullrequest_update for updating reviewer list

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    @jsonify

    def update(self, repo_name, pull_request_id):

        pull_request = PullRequest.get_or_404(pull_request_id)

        if pull_request.is_closed():

            raise HTTPForbidden()

        #only owner or admin can update it

        owner = pull_request.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:

            reviewers_ids = map(int, filter(lambda v: v not in [None, ''],

                request.POST.get('reviewers_ids', '').split(',')))

            PullRequestModel().update_reviewers(pull_request_id, reviewers_ids)

            Session().commit()

            return True

        raise HTTPForbidden()

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    @jsonify

    def delete(self, repo_name, pull_request_id):

        pull_request = PullRequest.get_or_404(pull_request_id)

        #only owner can delete it !

        if pull_request.author.user_id == c.authuser.user_id:

            PullRequestModel().delete(pull_request)

            Session().commit()

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

                    category='success')

            return redirect(url('my_pullrequests'))

        raise HTTPForbidden()

    @LoginRequired()

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

                                   'repository.admin')

    def show(self, repo_name, pull_request_id, extra=None):

        repo_model = RepoModel()

        c.users_array = repo_model.get_users_js()

        c.user_groups_array = repo_model.get_user_groups_js()

        c.pull_request = PullRequest.get_or_404(pull_request_id)

        c.allowed_to_change_status = self._get_is_allowed_change_status(c.pull_request)

        cc_model = ChangesetCommentsModel()

        cs_model = ChangesetStatusModel()

        # pull_requests repo_name we opened it against

        # ie. other_repo must match

        if repo_name != c.pull_request.other_repo.repo_name:

            raise HTTPNotFound

        # load compare data into template context

        c.cs_repo = c.pull_request.org_repo

        (c.cs_ref_type,

         c.cs_ref_name,

         c.cs_rev) = c.pull_request.org_ref.split(':')

        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

        c.cs_ranges = [org_scm_instance.get_changeset(x) for x in c.pull_request.revisions]

        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.available = []

        c.cs_branch_name = c.cs_ref_name

        other_scm_instance = c.a_repo.scm_instance

        c.update_msg = ""

        c.update_msg_other = ""

        if 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 descendent of target ref name

            if 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

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

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

                                                    revs[0], c.cs_branch_name, revs[0])

                if arevs:

                    if c.pull_request.is_closed():

                        c.update_msg = _('This pull request has been closed and can not be updated with descendent changes on %s:') % c.cs_branch_name

                    else:

                        c.update_msg = _('This pull request can be updated with descendent changes on %s:') % c.cs_branch_name

                    c.available = [org_scm_instance.get_changeset(x) for x in arevs]

                else:

                    c.update_msg = _('No changesets found for updating this pull request.')

        elif org_scm_instance.alias == 'git':

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

        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 = 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))

        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)

        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 = 0

        close_pr = False

        allowed_to_change_status = self._get_is_allowed_change_status(pull_request)

        if allowed_to_change_status:

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

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

        text = request.POST.get('text', '').strip() or _('No comments.')

        if close_pr:

            text = _('Closing.') + '\n' + text

        comm = ChangesetCommentsModel().create(

            text=text,

            repo=c.db_repo.repo_id,

            user=c.authuser.user_id,

            pull_request=pull_request_id,

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

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

            status_change=(ChangesetStatus.get_status_lbl(status)

                           if status and allowed_to_change_status else None),

            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 allowed_to_change_status:

            # get status if set !

            if status:

                ChangesetStatusModel().set_status(

                    c.db_repo.repo_id,

                    status,

                    c.authuser.user_id,

                    comm,

                    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'):

            return redirect(pull_request.url())

        data = {

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

        }

        if comm:

            c.co = comm

            data.update(comm.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()