rmap.connect('pullrequest_copy_update',

                 '/{repo_name:.*?}/pull-request-update/{pull_request_id}', controller='pullrequests',

                 action='copy_update', conditions=dict(function=check_repo,

                                                       method=["POST"]))

import re

         c.other_rev) = pull_request.other_ref.split(':') # other_rev is ancestor

        c.available = []

        c.org_branch_name = c.org_ref_name

        if org_scm_instance.alias == 'hg' and c.other_ref_name != 'ancestor':

            if c.org_ref_type != 'branch':

                c.org_branch_name = org_scm_instance.get_changeset(c.org_ref_name).branch # use ref_type ?

            other_branch_name = c.other_ref_name

            if c.other_ref_type != 'branch':

                other_branch_name = c.other_repo.scm_instance.get_changeset(c.other_ref_name).branch # use ref_type ?

            # 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

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

                                                revs[0], c.org_branch_name,

                                                revs[0], revs[0], other_branch_name)

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

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

    def copy_update(self, repo_name, pull_request_id):

        old_pull_request = PullRequest.get_or_404(pull_request_id)

        assert old_pull_request.other_repo.repo_name == repo_name

        org_repo = RepoModel()._get_repo(old_pull_request.org_repo.repo_name)

        org_ref_type, org_ref_name, org_rev = old_pull_request.org_ref.split(':')

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

        if updaterev:

            new_org_rev = self._get_ref_rev(org_repo, 'rev', updaterev)

        else:

            # assert org_ref_type == 'branch', org_ref_type # TODO: what if not?

            new_org_rev = self._get_ref_rev(org_repo, org_ref_type, org_ref_name)

        other_repo = RepoModel()._get_repo(old_pull_request.other_repo.repo_name)

        other_ref_type, other_ref_name, other_rev = old_pull_request.other_ref.split(':') # other_rev is ancestor

        #assert other_ref_type == 'branch', other_ref_type # TODO: what if not?

        new_other_rev = self._get_ref_rev(other_repo, other_ref_type, other_ref_name)

        cs_ranges, _cs_ranges_not, ancestor_rev = CompareController._get_changesets(org_repo.scm_instance.alias,

            other_repo.scm_instance, new_other_rev, # org and other "swapped"

            org_repo.scm_instance, new_org_rev)

        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".' %

                 (url('pullrequest_show', repo_name=old_pull_request.other_repo.repo_name,

                      pull_request_id=pull_request_id, qualified=True),

                  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), desc))

            if ancestor_rev == other_rev:

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

                             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),

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

            else:

                infos.append(_('This pull request uses another merge ancestor than the previous version and they are not directly comparable.'))

        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(url('pullrequest_show', repo_name=repo_name,

                                pull_request_id=pull_request_id))

        comm = ChangesetCommentsModel().create(

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

                                                   repo_name=old_pull_request.other_repo.repo_name,

                                                   pull_request_id=pull_request.pull_request_id,

                                                   qualified=True),

            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(url('pullrequest_show', repo_name=old_pull_request.other_repo.repo_name,

                            pull_request_id=pull_request.pull_request_id))

    # pullrequest_post for PR editing

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    # pullrequest_update for updating reviewer list

              <label>${_('Origin')}:</label>

            <div>

              ${h.link_to_ref(c.pull_request.org_repo.repo_name, c.org_ref_type, c.org_ref_name, c.org_rev)}

              %if c.org_ref_type != 'branch':

                ${_('on')} ${h.link_to_ref(c.pull_request.org_repo.repo_name, 'branch', c.org_branch_name)}

              %endif

            </div>

              <label>${_('Target')}:</label>

              ${h.link_to_ref(c.pull_request.other_repo.repo_name, c.other_ref_type, c.other_ref_name)}

              ## we don't know other rev - c.other_rev is ancestor and not necessarily on other_name_branch branch

        ${h.form(url('pullrequest_copy_update',repo_name=c.repo_name,pull_request_id=c.pull_request.pull_request_id), method='post')}

          <div class="field">

            <div class="label-summary">

              <label>${_('Update')}:</label>

            </div>

            %if c.available:

              <div class="input" style="max-height:200px; overflow-y:auto; overflow-x:hidden">

                ${_("Changesets on %s not included in this pull request:") % c.org_branch_name}

                <table class="noborder">

                  %for cnt, cs in enumerate(reversed(c.available)):

                    <tr>

                    <td>${h.radio(name='updaterev', value=cs.raw_id)}</td>

                    <td>${h.link_to(h.show_id(cs),h.url('changeset_home',repo_name=c.org_repo.repo_name,revision=cs.raw_id))}</td>

                    <td><div class="message" style="white-space:normal; height:1.1em; max-width: 500px; padding:0">${h.urlify_commit(cs.message, c.repo_name)}</div></td>

                    </tr>

                  %endfor

                </table>

              </div>

              <div class="buttons">

                ${h.submit('copy_update',_('Create pull request update'),class_="btn btn-small")}

              </div>

            %else:

              <div class="input">

                ${_("No changesets found for updating this pull request.")}

              </div>

            %endif

          </div>

        ${h.end_form()}