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())

        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')

    # 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')

    # 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_account_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)

        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'):

        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()

    _revisions = Column('revisions', UnicodeText(20500))  # 500 revisions max

    org_repo_id = Column('org_repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    org_ref = Column('org_ref', Unicode(256), nullable=False)

    other_repo_id = Column('other_repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    other_ref = Column('other_ref', Unicode(256), nullable=False)

    @hybrid_property

    def revisions(self):

        return self._revisions.split(':')

    @revisions.setter

    def revisions(self, val):

        self._revisions = ':'.join(val)

    @property

    def org_ref_parts(self):

        return self.org_ref.split(':')

    @property

    def other_ref_parts(self):

        return self.other_ref.split(':')

    author = relationship('User', lazy='joined')

    reviewers = relationship('PullRequestReviewers',

                             cascade="all, delete, delete-orphan")

    org_repo = relationship('Repository', primaryjoin='PullRequest.org_repo_id==Repository.repo_id')

    other_repo = relationship('Repository', primaryjoin='PullRequest.other_repo_id==Repository.repo_id')

    statuses = relationship('ChangesetStatus')

    comments = relationship('ChangesetComment',

                             cascade="all, delete, delete-orphan")

    def is_closed(self):

        return self.status == self.STATUS_CLOSED

    @property

    def last_review_status(self):

        return str(self.statuses[-1].status) if self.statuses else ''

    def __json__(self):

        return dict(

            revisions=self.revisions

        )

    def url(self, **kwargs):

        canonical = kwargs.pop('canonical', None)

        import kallithea.lib.helpers as h

        s = '/' + self.title

        b = self.org_ref_parts[1]

            s = '/_%s_%s' % (b, s)

        kwargs['extra'] = urlreadable(s)

        if canonical:

            return h.canonical_url('pullrequest_show', repo_name=self.other_repo.repo_name,

                                   pull_request_id=self.pull_request_id, **kwargs)

        return h.url('pullrequest_show', repo_name=self.other_repo.repo_name,

                     pull_request_id=self.pull_request_id, **kwargs)

class PullRequestReviewers(Base, BaseModel):

    __tablename__ = 'pull_request_reviewers'

    __table_args__ = (

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8', 'sqlite_autoincrement': True},

    )

    def __init__(self, user=None, pull_request=None):

        self.user = user

        self.pull_request = pull_request

    pull_requests_reviewers_id = Column('pull_requests_reviewers_id', Integer(), nullable=False, primary_key=True)

    pull_request_id = Column("pull_request_id", Integer(), ForeignKey('pull_requests.pull_request_id'), nullable=False)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=True)

    user = relationship('User')

    pull_request = relationship('PullRequest')

class Notification(Base, BaseModel):

    __tablename__ = 'notifications'

    __table_args__ = (

        Index('notification_type_idx', 'type'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8', 'sqlite_autoincrement': True},

    )

    TYPE_CHANGESET_COMMENT = u'cs_comment'

    TYPE_MESSAGE = u'message'

    TYPE_MENTION = u'mention'

    TYPE_REGISTRATION = u'registration'

    TYPE_PULL_REQUEST = u'pull_request'

    TYPE_PULL_REQUEST_COMMENT = u'pull_request_comment'

    notification_id = Column('notification_id', Integer(), nullable=False, primary_key=True)

    subject = Column('subject', Unicode(512), nullable=True)

    body = Column('body', UnicodeText(50000), nullable=True)

    created_by = Column("created_by", Integer(), ForeignKey('users.user_id'), nullable=True)

    created_on = Column('created_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    type_ = Column('type', Unicode(256))