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

        if not (h.HasPermissionAny('hg.admin')() or repo_admin or owner):

            raise HTTPForbidden()

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

        reviewers_ids = [int(s) for s in _form['review_members']]

        if _form['updaterev']:

            return self.create_new_iteration(pull_request,

                                      _form['updaterev'],

                                      _form['pullrequest_title'],

                                      _form['pullrequest_desc'],

                                      reviewers_ids)

        old_description = pull_request.description

        pull_request.title = _form['pullrequest_title']

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

        pull_request.owner = User.get_by_username(_form['owner'])

        user = User.get(c.authuser.user_id)

        try:

            PullRequestModel().mention_from_description(user, pull_request, old_description)

            PullRequestModel().update_reviewers(user, pull_request_id, reviewers_ids)

        except UserInvalidException as u:

            h.flash(_('Invalid reviewer "%s" specified') % u, category='error')

            raise HTTPBadRequest()

        Session().commit()

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

        raise HTTPFound(location=pull_request.url())

    @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.owner.user_id == c.authuser.user_id:

            PullRequestModel().delete(pull_request)

            Session().commit()

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

                    category='success')

            raise HTTPFound(location=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

        try:

            c.cs_ranges = [org_scm_instance.get_changeset(x)

                           for x in c.pull_request.revisions]

        except ChangesetDoesNotExistError:

            c.cs_ranges = []

        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.is_range = False

        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

        avail_revs = set()

        avail_show = []

        c.cs_branch_name = c.cs_ref_name

        other_scm_instance = c.a_repo.scm_instance

        c.update_msg = ""

        c.update_msg_other = ""

        try:

            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 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 changes are available on %s:') % c.cs_branch_name

                    else:

                        show = set()

                        avail_revs = set() # drop revs[0]

                        c.update_msg = _('No 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: revision %s was not found. Please create a new pull request!') % 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