pull-requests: increase stability of concurrent pull requests creation by flushing prematurly the statuses of commits.

This is required to increase the versions on each concurrent call. Otherwise we could get into an integrity errors of commitsha+version+repo

rhodecode/model/changeset_status.py

@@ -1,393 +1,394 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2010-2018 RhodeCode GmbH
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License, version 3
 # (only), as published by the Free Software Foundation.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 # This program is dual-licensed. If you wish to learn more about the
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 
 import itertools
 import logging
 import collections
 
 from rhodecode.model import BaseModel
 from rhodecode.model.db import (
     ChangesetStatus, ChangesetComment, PullRequest, Session)
 from rhodecode.lib.exceptions import StatusChangeOnClosedPullRequestError
 from rhodecode.lib.markup_renderer import (
     DEFAULT_COMMENTS_RENDERER, RstTemplateRenderer)
 
 log = logging.getLogger(__name__)
 
 
 class ChangesetStatusModel(BaseModel):
 
     cls = ChangesetStatus
 
     def __get_changeset_status(self, changeset_status):
         return self._get_instance(ChangesetStatus, changeset_status)
 
     def __get_pull_request(self, pull_request):
         return self._get_instance(PullRequest, pull_request)
 
     def _get_status_query(self, repo, revision, pull_request,
                           with_revisions=False):
         repo = self._get_repo(repo)
 
         q = ChangesetStatus.query()\
             .filter(ChangesetStatus.repo == repo)
         if not with_revisions:
             q = q.filter(ChangesetStatus.version == 0)
 
         if revision:
             q = q.filter(ChangesetStatus.revision == revision)
         elif pull_request:
             pull_request = self.__get_pull_request(pull_request)
             # TODO: johbo: Think about the impact of this join, there must
             # be a reason why ChangesetStatus and ChanagesetComment is linked
             # to the pull request. Might be that we want to do the same for
             # the pull_request_version_id.
             q = q.join(ChangesetComment).filter(
                 ChangesetStatus.pull_request == pull_request,
                 ChangesetComment.pull_request_version_id == None)
         else:
             raise Exception('Please specify revision or pull_request')
         q = q.order_by(ChangesetStatus.version.asc())
         return q
 
     def calculate_group_vote(self, group_id, group_statuses_by_reviewers,
                              trim_votes=True):
         """
         Calculate status based on given group members, and voting rule
 
 
         group1 - 4 members, 3 required for approval
             user1 - approved
             user2 - reject
             user3 - approved
             user4 - rejected
 
         final_state: rejected, reasons not at least 3 votes
 
 
         group1 - 4 members, 2 required for approval
             user1 - approved
             user2 - reject
             user3 - approved
             user4 - rejected
 
         final_state: approved, reasons got at least 2 approvals
 
         group1 - 4 members, ALL required for approval
             user1 - approved
             user2 - reject
             user3 - approved
             user4 - rejected
 
         final_state: rejected, reasons not all approvals
 
 
         group1 - 4 members, ALL required for approval
             user1 - approved
             user2 - approved
             user3 - approved
             user4 - approved
 
         final_state: approved, reason all approvals received
 
         group1 - 4 members, 5 required for approval
             (approval should be shorted to number of actual members)
 
             user1 - approved
             user2 - approved
             user3 - approved
             user4 - approved
 
         final_state: approved, reason all approvals received
 
         """
         group_vote_data = {}
         got_rule = False
         members = collections.OrderedDict()
         for review_obj, user, reasons, mandatory, statuses \
                 in group_statuses_by_reviewers:
 
             if not got_rule:
                 group_vote_data = review_obj.rule_user_group_data()
                 got_rule = bool(group_vote_data)
 
             members[user.user_id] = statuses
 
         if not group_vote_data:
             return []
 
         required_votes = group_vote_data['vote_rule']
         if required_votes == -1:
             # -1 means all required, so we replace it with how many people
             # are in the members
             required_votes = len(members)
 
         if trim_votes and required_votes > len(members):
             # we require more votes than we have members in the group
             # in this case we trim the required votes to the number of members
             required_votes = len(members)
 
         approvals = sum([
             1 for statuses in members.values()
             if statuses and
                statuses[0][1].status == ChangesetStatus.STATUS_APPROVED])
 
         calculated_votes = []
         # we have all votes from users, now check if we have enough votes
         # to fill other
         fill_in = ChangesetStatus.STATUS_UNDER_REVIEW
         if approvals >= required_votes:
             fill_in = ChangesetStatus.STATUS_APPROVED
 
         for member, statuses in members.items():
             if statuses:
                 ver, latest = statuses[0]
                 if fill_in == ChangesetStatus.STATUS_APPROVED:
                     calculated_votes.append(fill_in)
                 else:
                     calculated_votes.append(latest.status)
             else:
                 calculated_votes.append(fill_in)
 
         return calculated_votes
 
     def calculate_status(self, statuses_by_reviewers):
         """
         Given the approval statuses from reviewers, calculates final approval
         status. There can only be 3 results, all approved, all rejected. If
         there is no consensus the PR is under review.
 
         :param statuses_by_reviewers:
         """
 
         def group_rule(element):
             review_obj = element[0]
             rule_data = review_obj.rule_user_group_data()
             if rule_data and rule_data['id']:
                 return rule_data['id']
 
         voting_groups = itertools.groupby(
             sorted(statuses_by_reviewers, key=group_rule), group_rule)
 
         voting_by_groups = [(x, list(y)) for x, y in voting_groups]
 
         reviewers_number = len(statuses_by_reviewers)
         votes = collections.defaultdict(int)
         for group, group_statuses_by_reviewers in voting_by_groups:
             if group:
                 # calculate how the "group" voted
                 for vote_status in self.calculate_group_vote(
                         group, group_statuses_by_reviewers):
                     votes[vote_status] += 1
             else:
 
                 for review_obj, user, reasons, mandatory, statuses \
                         in group_statuses_by_reviewers:
                     # individual vote
                     if statuses:
                         ver, latest = statuses[0]
                         votes[latest.status] += 1
 
         approved_votes_count = votes[ChangesetStatus.STATUS_APPROVED]
         rejected_votes_count = votes[ChangesetStatus.STATUS_REJECTED]
 
         # TODO(marcink): with group voting, how does rejected work,
         # do we ever get rejected state ?
 
         if approved_votes_count == reviewers_number:
             return ChangesetStatus.STATUS_APPROVED
 
         if rejected_votes_count == reviewers_number:
             return ChangesetStatus.STATUS_REJECTED
 
         return ChangesetStatus.STATUS_UNDER_REVIEW
 
     def get_statuses(self, repo, revision=None, pull_request=None,
                      with_revisions=False):
         q = self._get_status_query(repo, revision, pull_request,
                                    with_revisions)
         return q.all()
 
     def get_status(self, repo, revision=None, pull_request=None, as_str=True):
         """
         Returns latest status of changeset for given revision or for given
         pull request. Statuses are versioned inside a table itself and
         version == 0 is always the current one
 
         :param repo:
         :param revision: 40char hash or None
         :param pull_request: pull_request reference
         :param as_str: return status as string not object
         """
         q = self._get_status_query(repo, revision, pull_request)
 
         # need to use first here since there can be multiple statuses
         # returned from pull_request
         status = q.first()
         if as_str:
             status = status.status if status else status
             st = status or ChangesetStatus.DEFAULT
             return str(st)
         return status
 
     def _render_auto_status_message(
             self, status, commit_id=None, pull_request=None):
         """
         render the message using DEFAULT_COMMENTS_RENDERER (RST renderer),
         so it's always looking the same disregarding on which default
         renderer system is using.
 
         :param status: status text to change into
         :param commit_id: the commit_id we change the status for
         :param pull_request: the pull request we change the status for
         """
 
         new_status = ChangesetStatus.get_status_lbl(status)
 
         params = {
             'new_status_label': new_status,
             'pull_request': pull_request,
             'commit_id': commit_id,
         }
         renderer = RstTemplateRenderer()
         return renderer.render('auto_status_change.mako', **params)
 
     def set_status(self, repo, status, user, comment=None, revision=None,
                    pull_request=None, dont_allow_on_closed_pull_request=False):
         """
         Creates new status for changeset or updates the old ones bumping their
         version, leaving the current status at
 
         :param repo:
         :param revision:
         :param status:
         :param user:
         :param comment:
         :param dont_allow_on_closed_pull_request: don't allow a status change
             if last status was for pull request and it's closed. We shouldn't
             mess around this manually
         """
         repo = self._get_repo(repo)
 
         q = ChangesetStatus.query()
 
         if revision:
             q = q.filter(ChangesetStatus.repo == repo)
             q = q.filter(ChangesetStatus.revision == revision)
         elif pull_request:
             pull_request = self.__get_pull_request(pull_request)
             q = q.filter(ChangesetStatus.repo == pull_request.source_repo)
             q = q.filter(ChangesetStatus.revision.in_(pull_request.revisions))
         cur_statuses = q.all()
 
         # if statuses exists and last is associated with a closed pull request
         # we need to check if we can allow this status change
         if (dont_allow_on_closed_pull_request and cur_statuses
             and getattr(cur_statuses[0].pull_request, 'status', '')
                 == PullRequest.STATUS_CLOSED):
             raise StatusChangeOnClosedPullRequestError(
                 'Changing status on closed pull request is not allowed'
             )
 
         # update all current statuses with older version
         if cur_statuses:
             for st in cur_statuses:
                 st.version += 1
                 Session().add(st)
+            Session().flush()
 
         def _create_status(user, repo, status, comment, revision, pull_request):
             new_status = ChangesetStatus()
             new_status.author = self._get_user(user)
             new_status.repo = self._get_repo(repo)
             new_status.status = status
             new_status.comment = comment
             new_status.revision = revision
             new_status.pull_request = pull_request
             return new_status
 
         if not comment:
             from rhodecode.model.comment import CommentsModel
             comment = CommentsModel().create(
                 text=self._render_auto_status_message(
                     status, commit_id=revision, pull_request=pull_request),
                 repo=repo,
                 user=user,
                 pull_request=pull_request,
                 send_email=False, renderer=DEFAULT_COMMENTS_RENDERER
             )
 
         if revision:
             new_status = _create_status(
                 user=user, repo=repo, status=status, comment=comment,
                 revision=revision, pull_request=pull_request)
             Session().add(new_status)
             return new_status
         elif pull_request:
             # pull request can have more than one revision associated to it
             # we need to create new version for each one
             new_statuses = []
             repo = pull_request.source_repo
             for rev in pull_request.revisions:
                 new_status = _create_status(
                     user=user, repo=repo, status=status, comment=comment,
                     revision=rev, pull_request=pull_request)
                 new_statuses.append(new_status)
                 Session().add(new_status)
             return new_statuses
 
     def reviewers_statuses(self, pull_request):
         _commit_statuses = self.get_statuses(
             pull_request.source_repo,
             pull_request=pull_request,
             with_revisions=True)
 
         commit_statuses = collections.defaultdict(list)
         for st in _commit_statuses:
             commit_statuses[st.author.username] += [st]
 
         pull_request_reviewers = []
 
         def version(commit_status):
             return commit_status.version
 
         for obj in pull_request.reviewers:
             if not obj.user:
                 continue
             statuses = commit_statuses.get(obj.user.username, None)
             if statuses:
                 status_groups = itertools.groupby(
                     sorted(statuses, key=version), version)
                 statuses = [(x, list(y)[0]) for x, y in status_groups]
 
             pull_request_reviewers.append(
                 (obj, obj.user, obj.reasons, obj.mandatory, statuses))
 
         return pull_request_reviewers
 
     def calculated_review_status(self, pull_request, reviewers_statuses=None):
         """
         calculate pull request status based on reviewers, it should be a list
         of two element lists.
 
         :param reviewers_statuses:
         """
         reviewers = reviewers_statuses or self.reviewers_statuses(pull_request)
         return self.calculate_status(reviewers)

rhodecode/model/pull_request.py

@@ -1,1739 +1,1739 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2012-2018 RhodeCode GmbH
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License, version 3
 # (only), as published by the Free Software Foundation.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 # This program is dual-licensed. If you wish to learn more about the
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 
 """
 pull request model for RhodeCode
 """
 
 
 import json
 import logging
 import datetime
 import urllib
 import collections
 
 from pyramid.threadlocal import get_current_request
 
 from rhodecode import events
 from rhodecode.translation import lazy_ugettext#, _
 from rhodecode.lib import helpers as h, hooks_utils, diffs
 from rhodecode.lib import audit_logger
 from rhodecode.lib.compat import OrderedDict
 from rhodecode.lib.hooks_daemon import prepare_callback_daemon
 from rhodecode.lib.markup_renderer import (
     DEFAULT_COMMENTS_RENDERER, RstTemplateRenderer)
 from rhodecode.lib.utils2 import safe_unicode, safe_str, md5_safe
 from rhodecode.lib.vcs.backends.base import (
     Reference, MergeResponse, MergeFailureReason, UpdateFailureReason)
 from rhodecode.lib.vcs.conf import settings as vcs_settings
 from rhodecode.lib.vcs.exceptions import (
     CommitDoesNotExistError, EmptyRepositoryError)
 from rhodecode.model import BaseModel
 from rhodecode.model.changeset_status import ChangesetStatusModel
 from rhodecode.model.comment import CommentsModel
 from rhodecode.model.db import (
     or_, PullRequest, PullRequestReviewers, ChangesetStatus,
     PullRequestVersion, ChangesetComment, Repository, RepoReviewRule)
 from rhodecode.model.meta import Session
 from rhodecode.model.notification import NotificationModel, \
     EmailNotificationModel
 from rhodecode.model.scm import ScmModel
 from rhodecode.model.settings import VcsSettingsModel
 
 
 log = logging.getLogger(__name__)
 
 
 # Data structure to hold the response data when updating commits during a pull
 # request update.
 UpdateResponse = collections.namedtuple('UpdateResponse', [
     'executed', 'reason', 'new', 'old', 'changes',
     'source_changed', 'target_changed'])
 
 
 class PullRequestModel(BaseModel):
 
     cls = PullRequest
 
     DIFF_CONTEXT = diffs.DEFAULT_CONTEXT
 
     MERGE_STATUS_MESSAGES = {
         MergeFailureReason.NONE: lazy_ugettext(
             'This pull request can be automatically merged.'),
         MergeFailureReason.UNKNOWN: lazy_ugettext(
             'This pull request cannot be merged because of an unhandled'
             ' exception.'),
         MergeFailureReason.MERGE_FAILED: lazy_ugettext(
             'This pull request cannot be merged because of merge conflicts.'),
         MergeFailureReason.PUSH_FAILED: lazy_ugettext(
             'This pull request could not be merged because push to target'
             ' failed.'),
         MergeFailureReason.TARGET_IS_NOT_HEAD: lazy_ugettext(
             'This pull request cannot be merged because the target is not a'
             ' head.'),
         MergeFailureReason.HG_SOURCE_HAS_MORE_BRANCHES: lazy_ugettext(
             'This pull request cannot be merged because the source contains'
             ' more branches than the target.'),
         MergeFailureReason.HG_TARGET_HAS_MULTIPLE_HEADS: lazy_ugettext(
             'This pull request cannot be merged because the target has'
             ' multiple heads.'),
         MergeFailureReason.TARGET_IS_LOCKED: lazy_ugettext(
             'This pull request cannot be merged because the target repository'
             ' is locked.'),
         MergeFailureReason._DEPRECATED_MISSING_COMMIT: lazy_ugettext(
             'This pull request cannot be merged because the target or the '
             'source reference is missing.'),
         MergeFailureReason.MISSING_TARGET_REF: lazy_ugettext(
             'This pull request cannot be merged because the target '
             'reference is missing.'),
         MergeFailureReason.MISSING_SOURCE_REF: lazy_ugettext(
             'This pull request cannot be merged because the source '
             'reference is missing.'),
         MergeFailureReason.SUBREPO_MERGE_FAILED: lazy_ugettext(
             'This pull request cannot be merged because of conflicts related '
             'to sub repositories.'),
     }
 
     UPDATE_STATUS_MESSAGES = {
         UpdateFailureReason.NONE: lazy_ugettext(
             'Pull request update successful.'),
         UpdateFailureReason.UNKNOWN: lazy_ugettext(
             'Pull request update failed because of an unknown error.'),
         UpdateFailureReason.NO_CHANGE: lazy_ugettext(
             'No update needed because the source and target have not changed.'),
         UpdateFailureReason.WRONG_REF_TYPE: lazy_ugettext(
             'Pull request cannot be updated because the reference type is '
             'not supported for an update. Only Branch, Tag or Bookmark is allowed.'),
         UpdateFailureReason.MISSING_TARGET_REF: lazy_ugettext(
             'This pull request cannot be updated because the target '
             'reference is missing.'),
         UpdateFailureReason.MISSING_SOURCE_REF: lazy_ugettext(
             'This pull request cannot be updated because the source '
             'reference is missing.'),
     }
     REF_TYPES = ['bookmark', 'book', 'tag', 'branch']
     UPDATABLE_REF_TYPES = ['bookmark', 'book', 'branch']
 
     def __get_pull_request(self, pull_request):
         return self._get_instance((
             PullRequest, PullRequestVersion), pull_request)
 
     def _check_perms(self, perms, pull_request, user, api=False):
         if not api:
             return h.HasRepoPermissionAny(*perms)(
                 user=user, repo_name=pull_request.target_repo.repo_name)
         else:
             return h.HasRepoPermissionAnyApi(*perms)(
                 user=user, repo_name=pull_request.target_repo.repo_name)
 
     def check_user_read(self, pull_request, user, api=False):
         _perms = ('repository.admin', 'repository.write', 'repository.read',)
         return self._check_perms(_perms, pull_request, user, api)
 
     def check_user_merge(self, pull_request, user, api=False):
         _perms = ('repository.admin', 'repository.write', 'hg.admin',)
         return self._check_perms(_perms, pull_request, user, api)
 
     def check_user_update(self, pull_request, user, api=False):
         owner = user.user_id == pull_request.user_id
         return self.check_user_merge(pull_request, user, api) or owner
 
     def check_user_delete(self, pull_request, user):
         owner = user.user_id == pull_request.user_id
         _perms = ('repository.admin',)
         return self._check_perms(_perms, pull_request, user) or owner
 
     def check_user_change_status(self, pull_request, user, api=False):
         reviewer = user.user_id in [x.user_id for x in
                                     pull_request.reviewers]
         return self.check_user_update(pull_request, user, api) or reviewer
 
     def check_user_comment(self, pull_request, user):
         owner = user.user_id == pull_request.user_id
         return self.check_user_read(pull_request, user) or owner
 
     def get(self, pull_request):
         return self.__get_pull_request(pull_request)
 
     def _prepare_get_all_query(self, repo_name, source=False, statuses=None,
                                opened_by=None, order_by=None,
                                order_dir='desc'):
         repo = None
         if repo_name:
             repo = self._get_repo(repo_name)
 
         q = PullRequest.query()
 
         # source or target
         if repo and source:
             q = q.filter(PullRequest.source_repo == repo)
         elif repo:
             q = q.filter(PullRequest.target_repo == repo)
 
         # closed,opened
         if statuses:
             q = q.filter(PullRequest.status.in_(statuses))
 
         # opened by filter
         if opened_by:
             q = q.filter(PullRequest.user_id.in_(opened_by))
 
         if order_by:
             order_map = {
                 'name_raw': PullRequest.pull_request_id,
                 'title': PullRequest.title,
                 'updated_on_raw': PullRequest.updated_on,
                 'target_repo': PullRequest.target_repo_id
             }
             if order_dir == 'asc':
                 q = q.order_by(order_map[order_by].asc())
             else:
                 q = q.order_by(order_map[order_by].desc())
 
         return q
 
     def count_all(self, repo_name, source=False, statuses=None,
                   opened_by=None):
         """
         Count the number of pull requests for a specific repository.
 
         :param repo_name: target or source repo
         :param source: boolean flag to specify if repo_name refers to source
         :param statuses: list of pull request statuses
         :param opened_by: author user of the pull request
         :returns: int number of pull requests
         """
         q = self._prepare_get_all_query(
             repo_name, source=source, statuses=statuses, opened_by=opened_by)
 
         return q.count()
 
     def get_all(self, repo_name, source=False, statuses=None, opened_by=None,
                 offset=0, length=None, order_by=None, order_dir='desc'):
         """
         Get all pull requests for a specific repository.
 
         :param repo_name: target or source repo
         :param source: boolean flag to specify if repo_name refers to source
         :param statuses: list of pull request statuses
         :param opened_by: author user of the pull request
         :param offset: pagination offset
         :param length: length of returned list
         :param order_by: order of the returned list
         :param order_dir: 'asc' or 'desc' ordering direction
         :returns: list of pull requests
         """
         q = self._prepare_get_all_query(
             repo_name, source=source, statuses=statuses, opened_by=opened_by,
             order_by=order_by, order_dir=order_dir)
 
         if length:
             pull_requests = q.limit(length).offset(offset).all()
         else:
             pull_requests = q.all()
 
         return pull_requests
 
     def count_awaiting_review(self, repo_name, source=False, statuses=None,
                               opened_by=None):
         """
         Count the number of pull requests for a specific repository that are
         awaiting review.
 
         :param repo_name: target or source repo
         :param source: boolean flag to specify if repo_name refers to source
         :param statuses: list of pull request statuses
         :param opened_by: author user of the pull request
         :returns: int number of pull requests
         """
         pull_requests = self.get_awaiting_review(
             repo_name, source=source, statuses=statuses, opened_by=opened_by)
 
         return len(pull_requests)
 
     def get_awaiting_review(self, repo_name, source=False, statuses=None,
                             opened_by=None, offset=0, length=None,
                             order_by=None, order_dir='desc'):
         """
         Get all pull requests for a specific repository that are awaiting
         review.
 
         :param repo_name: target or source repo
         :param source: boolean flag to specify if repo_name refers to source
         :param statuses: list of pull request statuses
         :param opened_by: author user of the pull request
         :param offset: pagination offset
         :param length: length of returned list
         :param order_by: order of the returned list
         :param order_dir: 'asc' or 'desc' ordering direction
         :returns: list of pull requests
         """
         pull_requests = self.get_all(
             repo_name, source=source, statuses=statuses, opened_by=opened_by,
             order_by=order_by, order_dir=order_dir)
 
         _filtered_pull_requests = []
         for pr in pull_requests:
             status = pr.calculated_review_status()
             if status in [ChangesetStatus.STATUS_NOT_REVIEWED,
                           ChangesetStatus.STATUS_UNDER_REVIEW]:
                 _filtered_pull_requests.append(pr)
         if length:
             return _filtered_pull_requests[offset:offset+length]
         else:
             return _filtered_pull_requests
 
     def count_awaiting_my_review(self, repo_name, source=False, statuses=None,
                                  opened_by=None, user_id=None):
         """
         Count the number of pull requests for a specific repository that are
         awaiting review from a specific user.
 
         :param repo_name: target or source repo
         :param source: boolean flag to specify if repo_name refers to source
         :param statuses: list of pull request statuses
         :param opened_by: author user of the pull request
         :param user_id: reviewer user of the pull request
         :returns: int number of pull requests
         """
         pull_requests = self.get_awaiting_my_review(
             repo_name, source=source, statuses=statuses, opened_by=opened_by,
             user_id=user_id)
 
         return len(pull_requests)
 
     def get_awaiting_my_review(self, repo_name, source=False, statuses=None,
                                opened_by=None, user_id=None, offset=0,
                                length=None, order_by=None, order_dir='desc'):
         """
         Get all pull requests for a specific repository that are awaiting
         review from a specific user.
 
         :param repo_name: target or source repo
         :param source: boolean flag to specify if repo_name refers to source
         :param statuses: list of pull request statuses
         :param opened_by: author user of the pull request
         :param user_id: reviewer user of the pull request
         :param offset: pagination offset
         :param length: length of returned list
         :param order_by: order of the returned list
         :param order_dir: 'asc' or 'desc' ordering direction
         :returns: list of pull requests
         """
         pull_requests = self.get_all(
             repo_name, source=source, statuses=statuses, opened_by=opened_by,
             order_by=order_by, order_dir=order_dir)
 
         _my = PullRequestModel().get_not_reviewed(user_id)
         my_participation = []
         for pr in pull_requests:
             if pr in _my:
                 my_participation.append(pr)
         _filtered_pull_requests = my_participation
         if length:
             return _filtered_pull_requests[offset:offset+length]
         else:
             return _filtered_pull_requests
 
     def get_not_reviewed(self, user_id):
         return [
             x.pull_request for x in PullRequestReviewers.query().filter(
                 PullRequestReviewers.user_id == user_id).all()
         ]
 
     def _prepare_participating_query(self, user_id=None, statuses=None,
                                      order_by=None, order_dir='desc'):
         q = PullRequest.query()
         if user_id:
             reviewers_subquery = Session().query(
                 PullRequestReviewers.pull_request_id).filter(
                 PullRequestReviewers.user_id == user_id).subquery()
             user_filter = or_(
                 PullRequest.user_id == user_id,
                 PullRequest.pull_request_id.in_(reviewers_subquery)
             )
             q = PullRequest.query().filter(user_filter)
 
         # closed,opened
         if statuses:
             q = q.filter(PullRequest.status.in_(statuses))
 
         if order_by:
             order_map = {
                 'name_raw': PullRequest.pull_request_id,
                 'title': PullRequest.title,
                 'updated_on_raw': PullRequest.updated_on,
                 'target_repo': PullRequest.target_repo_id
             }
             if order_dir == 'asc':
                 q = q.order_by(order_map[order_by].asc())
             else:
                 q = q.order_by(order_map[order_by].desc())
 
         return q
 
     def count_im_participating_in(self, user_id=None, statuses=None):
         q = self._prepare_participating_query(user_id, statuses=statuses)
         return q.count()
 
     def get_im_participating_in(
             self, user_id=None, statuses=None, offset=0,
             length=None, order_by=None, order_dir='desc'):
         """
         Get all Pull requests that i'm participating in, or i have opened
         """
 
         q = self._prepare_participating_query(
             user_id, statuses=statuses, order_by=order_by,
             order_dir=order_dir)
 
         if length:
             pull_requests = q.limit(length).offset(offset).all()
         else:
             pull_requests = q.all()
 
         return pull_requests
 
     def get_versions(self, pull_request):
         """
         returns version of pull request sorted by ID descending
         """
         return PullRequestVersion.query()\
             .filter(PullRequestVersion.pull_request == pull_request)\
             .order_by(PullRequestVersion.pull_request_version_id.asc())\
             .all()
 
     def get_pr_version(self, pull_request_id, version=None):
         at_version = None
 
         if version and version == 'latest':
             pull_request_ver = PullRequest.get(pull_request_id)
             pull_request_obj = pull_request_ver
             _org_pull_request_obj = pull_request_obj
             at_version = 'latest'
         elif version:
             pull_request_ver = PullRequestVersion.get_or_404(version)
             pull_request_obj = pull_request_ver
             _org_pull_request_obj = pull_request_ver.pull_request
             at_version = pull_request_ver.pull_request_version_id
         else:
             _org_pull_request_obj = pull_request_obj = PullRequest.get_or_404(
                 pull_request_id)
 
         pull_request_display_obj = PullRequest.get_pr_display_object(
             pull_request_obj, _org_pull_request_obj)
 
         return _org_pull_request_obj, pull_request_obj, \
                pull_request_display_obj, at_version
 
     def create(self, created_by, source_repo, source_ref, target_repo,
                target_ref, revisions, reviewers, title, description=None,
                description_renderer=None,
                reviewer_data=None, translator=None, auth_user=None):
         translator = translator or get_current_request().translate
 
         created_by_user = self._get_user(created_by)
         auth_user = auth_user or created_by_user.AuthUser()
         source_repo = self._get_repo(source_repo)
         target_repo = self._get_repo(target_repo)
 
         pull_request = PullRequest()
         pull_request.source_repo = source_repo
         pull_request.source_ref = source_ref
         pull_request.target_repo = target_repo
         pull_request.target_ref = target_ref
         pull_request.revisions = revisions
         pull_request.title = title
         pull_request.description = description
         pull_request.description_renderer = description_renderer
         pull_request.author = created_by_user
         pull_request.reviewer_data = reviewer_data
 
         Session().add(pull_request)
         Session().flush()
 
         reviewer_ids = set()
         # members / reviewers
         for reviewer_object in reviewers:
             user_id, reasons, mandatory, rules = reviewer_object
             user = self._get_user(user_id)
 
             # skip duplicates
             if user.user_id in reviewer_ids:
                 continue
 
             reviewer_ids.add(user.user_id)
 
             reviewer = PullRequestReviewers()
             reviewer.user = user
             reviewer.pull_request = pull_request
             reviewer.reasons = reasons
             reviewer.mandatory = mandatory
 
             # NOTE(marcink): pick only first rule for now
             rule_id = list(rules)[0] if rules else None
             rule = RepoReviewRule.get(rule_id) if rule_id else None
             if rule:
                 review_group = rule.user_group_vote_rule(user_id)
                 # we check if this particular reviewer is member of a voting group
                 if review_group:
                     # NOTE(marcink):
                     # can be that user is member of more but we pick the first same,
                     # same as default reviewers algo
                     review_group = review_group[0]
 
                     rule_data = {
                         'rule_name':
                             rule.review_rule_name,
                         'rule_user_group_entry_id':
                             review_group.repo_review_rule_users_group_id,
                         'rule_user_group_name':
                             review_group.users_group.users_group_name,
                         'rule_user_group_members':
                             [x.user.username for x in review_group.users_group.members],
                         'rule_user_group_members_id':
                             [x.user.user_id for x in review_group.users_group.members],
                     }
                     # e.g {'vote_rule': -1, 'mandatory': True}
                     rule_data.update(review_group.rule_data())
 
                     reviewer.rule_data = rule_data
 
             Session().add(reviewer)
             Session().flush()
 
         # Set approval status to "Under Review" for all commits which are
         # part of this pull request.
         ChangesetStatusModel().set_status(
             repo=target_repo,
             status=ChangesetStatus.STATUS_UNDER_REVIEW,
             user=created_by_user,
             pull_request=pull_request
         )
         # we commit early at this point. This has to do with a fact
         # that before queries do some row-locking. And because of that
-        # we need to commit and finish transation before below validate call
+        # we need to commit and finish transaction before below validate call
         # that for large repos could be long resulting in long row locks
         Session().commit()
 
         # prepare workspace, and run initial merge simulation
         MergeCheck.validate(
             pull_request, auth_user=auth_user, translator=translator)
 
         self.notify_reviewers(pull_request, reviewer_ids)
         self._trigger_pull_request_hook(
             pull_request, created_by_user, 'create')
 
         creation_data = pull_request.get_api_data(with_merge_state=False)
         self._log_audit_action(
             'repo.pull_request.create', {'data': creation_data},
             auth_user, pull_request)
 
         return pull_request
 
     def _trigger_pull_request_hook(self, pull_request, user, action):
         pull_request = self.__get_pull_request(pull_request)
         target_scm = pull_request.target_repo.scm_instance()
         if action == 'create':
             trigger_hook = hooks_utils.trigger_log_create_pull_request_hook
         elif action == 'merge':
             trigger_hook = hooks_utils.trigger_log_merge_pull_request_hook
         elif action == 'close':
             trigger_hook = hooks_utils.trigger_log_close_pull_request_hook
         elif action == 'review_status_change':
             trigger_hook = hooks_utils.trigger_log_review_pull_request_hook
         elif action == 'update':
             trigger_hook = hooks_utils.trigger_log_update_pull_request_hook
         else:
             return
 
         trigger_hook(
             username=user.username,
             repo_name=pull_request.target_repo.repo_name,
             repo_alias=target_scm.alias,
             pull_request=pull_request)
 
     def _get_commit_ids(self, pull_request):
         """
         Return the commit ids of the merged pull request.
 
         This method is not dealing correctly yet with the lack of autoupdates
         nor with the implicit target updates.
         For example: if a commit in the source repo is already in the target it
         will be reported anyways.
         """
         merge_rev = pull_request.merge_rev
         if merge_rev is None:
             raise ValueError('This pull request was not merged yet')
 
         commit_ids = list(pull_request.revisions)
         if merge_rev not in commit_ids:
             commit_ids.append(merge_rev)
 
         return commit_ids
 
     def merge_repo(self, pull_request, user, extras):
         log.debug("Merging pull request %s", pull_request.pull_request_id)
         extras['user_agent'] = 'internal-merge'
         merge_state = self._merge_pull_request(pull_request, user, extras)
         if merge_state.executed:
             log.debug(
                 "Merge was successful, updating the pull request comments.")
             self._comment_and_close_pr(pull_request, user, merge_state)
 
             self._log_audit_action(
                 'repo.pull_request.merge',
                 {'merge_state': merge_state.__dict__},
                 user, pull_request)
 
         else:
             log.warn("Merge failed, not updating the pull request.")
         return merge_state
 
     def _merge_pull_request(self, pull_request, user, extras, merge_msg=None):
         target_vcs = pull_request.target_repo.scm_instance()
         source_vcs = pull_request.source_repo.scm_instance()
 
         message = safe_unicode(merge_msg or vcs_settings.MERGE_MESSAGE_TMPL).format(
             pr_id=pull_request.pull_request_id,
             pr_title=pull_request.title,
             source_repo=source_vcs.name,
             source_ref_name=pull_request.source_ref_parts.name,
             target_repo=target_vcs.name,
             target_ref_name=pull_request.target_ref_parts.name,
         )
 
         workspace_id = self._workspace_id(pull_request)
         repo_id = pull_request.target_repo.repo_id
         use_rebase = self._use_rebase_for_merging(pull_request)
         close_branch = self._close_branch_before_merging(pull_request)
 
         target_ref = self._refresh_reference(
             pull_request.target_ref_parts, target_vcs)
 
         callback_daemon, extras = prepare_callback_daemon(
             extras, protocol=vcs_settings.HOOKS_PROTOCOL,
             host=vcs_settings.HOOKS_HOST,
             use_direct_calls=vcs_settings.HOOKS_DIRECT_CALLS)
 
         with callback_daemon:
             # TODO: johbo: Implement a clean way to run a config_override
             # for a single call.
             target_vcs.config.set(
                 'rhodecode', 'RC_SCM_DATA', json.dumps(extras))
 
             user_name = user.short_contact
             merge_state = target_vcs.merge(
                 repo_id, workspace_id, target_ref, source_vcs,
                 pull_request.source_ref_parts,
                 user_name=user_name, user_email=user.email,
                 message=message, use_rebase=use_rebase,
                 close_branch=close_branch)
         return merge_state
 
     def _comment_and_close_pr(self, pull_request, user, merge_state, close_msg=None):
         pull_request.merge_rev = merge_state.merge_ref.commit_id
         pull_request.updated_on = datetime.datetime.now()
         close_msg = close_msg or 'Pull request merged and closed'
 
         CommentsModel().create(
             text=safe_unicode(close_msg),
             repo=pull_request.target_repo.repo_id,
             user=user.user_id,
             pull_request=pull_request.pull_request_id,
             f_path=None,
             line_no=None,
             closing_pr=True
         )
 
         Session().add(pull_request)
         Session().flush()
         # TODO: paris: replace invalidation with less radical solution
         ScmModel().mark_for_invalidation(
             pull_request.target_repo.repo_name)
         self._trigger_pull_request_hook(pull_request, user, 'merge')
 
     def has_valid_update_type(self, pull_request):
         source_ref_type = pull_request.source_ref_parts.type
         return source_ref_type in self.REF_TYPES
 
     def update_commits(self, pull_request):
         """
         Get the updated list of commits for the pull request
         and return the new pull request version and the list
         of commits processed by this update action
         """
         pull_request = self.__get_pull_request(pull_request)
         source_ref_type = pull_request.source_ref_parts.type
         source_ref_name = pull_request.source_ref_parts.name
         source_ref_id = pull_request.source_ref_parts.commit_id
 
         target_ref_type = pull_request.target_ref_parts.type
         target_ref_name = pull_request.target_ref_parts.name
         target_ref_id = pull_request.target_ref_parts.commit_id
 
         if not self.has_valid_update_type(pull_request):
             log.debug(
                 "Skipping update of pull request %s due to ref type: %s",
                 pull_request, source_ref_type)
             return UpdateResponse(
                 executed=False,
                 reason=UpdateFailureReason.WRONG_REF_TYPE,
                 old=pull_request, new=None, changes=None,
                 source_changed=False, target_changed=False)
 
         # source repo
         source_repo = pull_request.source_repo.scm_instance()
         try:
             source_commit = source_repo.get_commit(commit_id=source_ref_name)
         except CommitDoesNotExistError:
             return UpdateResponse(
                 executed=False,
                 reason=UpdateFailureReason.MISSING_SOURCE_REF,
                 old=pull_request, new=None, changes=None,
                 source_changed=False, target_changed=False)
 
         source_changed = source_ref_id != source_commit.raw_id
 
         # target repo
         target_repo = pull_request.target_repo.scm_instance()
         try:
             target_commit = target_repo.get_commit(commit_id=target_ref_name)
         except CommitDoesNotExistError:
             return UpdateResponse(
                 executed=False,
                 reason=UpdateFailureReason.MISSING_TARGET_REF,
                 old=pull_request, new=None, changes=None,
                 source_changed=False, target_changed=False)
         target_changed = target_ref_id != target_commit.raw_id
 
         if not (source_changed or target_changed):
             log.debug("Nothing changed in pull request %s", pull_request)
             return UpdateResponse(
                 executed=False,
                 reason=UpdateFailureReason.NO_CHANGE,
                 old=pull_request, new=None, changes=None,
                 source_changed=target_changed, target_changed=source_changed)
 
         change_in_found = 'target repo' if target_changed else 'source repo'
         log.debug('Updating pull request because of change in %s detected',
                   change_in_found)
 
         # Finally there is a need for an update, in case of source change
         # we create a new version, else just an update
         if source_changed:
             pull_request_version = self._create_version_from_snapshot(pull_request)
             self._link_comments_to_version(pull_request_version)
         else:
             try:
                 ver = pull_request.versions[-1]
             except IndexError:
                 ver = None
 
             pull_request.pull_request_version_id = \
                 ver.pull_request_version_id if ver else None
             pull_request_version = pull_request
 
         try:
             if target_ref_type in self.REF_TYPES:
                 target_commit = target_repo.get_commit(target_ref_name)
             else:
                 target_commit = target_repo.get_commit(target_ref_id)
         except CommitDoesNotExistError:
             return UpdateResponse(
                 executed=False,
                 reason=UpdateFailureReason.MISSING_TARGET_REF,
                 old=pull_request, new=None, changes=None,
                 source_changed=source_changed, target_changed=target_changed)
 
         # re-compute commit ids
         old_commit_ids = pull_request.revisions
         pre_load = ["author", "branch", "date", "message"]
         commit_ranges = target_repo.compare(
             target_commit.raw_id, source_commit.raw_id, source_repo, merge=True,
             pre_load=pre_load)
 
         ancestor = target_repo.get_common_ancestor(
             target_commit.raw_id, source_commit.raw_id, source_repo)
 
         pull_request.source_ref = '%s:%s:%s' % (
             source_ref_type, source_ref_name, source_commit.raw_id)
         pull_request.target_ref = '%s:%s:%s' % (
             target_ref_type, target_ref_name, ancestor)
 
         pull_request.revisions = [
             commit.raw_id for commit in reversed(commit_ranges)]
         pull_request.updated_on = datetime.datetime.now()
         Session().add(pull_request)
         new_commit_ids = pull_request.revisions
 
         old_diff_data, new_diff_data = self._generate_update_diffs(
             pull_request, pull_request_version)
 
         # calculate commit and file changes
         changes = self._calculate_commit_id_changes(
             old_commit_ids, new_commit_ids)
         file_changes = self._calculate_file_changes(
             old_diff_data, new_diff_data)
 
         # set comments as outdated if DIFFS changed
         CommentsModel().outdate_comments(
             pull_request, old_diff_data=old_diff_data,
             new_diff_data=new_diff_data)
 
         commit_changes = (changes.added or changes.removed)
         file_node_changes = (
             file_changes.added or file_changes.modified or file_changes.removed)
         pr_has_changes = commit_changes or file_node_changes
 
         # Add an automatic comment to the pull request, in case
         # anything has changed
         if pr_has_changes:
             update_comment = CommentsModel().create(
                 text=self._render_update_message(changes, file_changes),
                 repo=pull_request.target_repo,
                 user=pull_request.author,
                 pull_request=pull_request,
                 send_email=False, renderer=DEFAULT_COMMENTS_RENDERER)
 
             # Update status to "Under Review" for added commits
             for commit_id in changes.added:
                 ChangesetStatusModel().set_status(
                     repo=pull_request.source_repo,
                     status=ChangesetStatus.STATUS_UNDER_REVIEW,
                     comment=update_comment,
                     user=pull_request.author,
                     pull_request=pull_request,
                     revision=commit_id)
 
         log.debug(
             'Updated pull request %s, added_ids: %s, common_ids: %s, '
             'removed_ids: %s', pull_request.pull_request_id,
             changes.added, changes.common, changes.removed)
         log.debug(
             'Updated pull request with the following file changes: %s',
             file_changes)
 
         log.info(
             "Updated pull request %s from commit %s to commit %s, "
             "stored new version %s of this pull request.",
             pull_request.pull_request_id, source_ref_id,
             pull_request.source_ref_parts.commit_id,
             pull_request_version.pull_request_version_id)
         Session().commit()
         self._trigger_pull_request_hook(
             pull_request, pull_request.author, 'update')
 
         return UpdateResponse(
             executed=True, reason=UpdateFailureReason.NONE,
             old=pull_request, new=pull_request_version, changes=changes,
             source_changed=source_changed, target_changed=target_changed)
 
     def _create_version_from_snapshot(self, pull_request):
         version = PullRequestVersion()
         version.title = pull_request.title
         version.description = pull_request.description
         version.status = pull_request.status
         version.created_on = datetime.datetime.now()
         version.updated_on = pull_request.updated_on
         version.user_id = pull_request.user_id
         version.source_repo = pull_request.source_repo
         version.source_ref = pull_request.source_ref
         version.target_repo = pull_request.target_repo
         version.target_ref = pull_request.target_ref
 
         version._last_merge_source_rev = pull_request._last_merge_source_rev
         version._last_merge_target_rev = pull_request._last_merge_target_rev
         version.last_merge_status = pull_request.last_merge_status
         version.shadow_merge_ref = pull_request.shadow_merge_ref
         version.merge_rev = pull_request.merge_rev
         version.reviewer_data = pull_request.reviewer_data
 
         version.revisions = pull_request.revisions
         version.pull_request = pull_request
         Session().add(version)
         Session().flush()
 
         return version
 
     def _generate_update_diffs(self, pull_request, pull_request_version):
 
         diff_context = (
             self.DIFF_CONTEXT +
             CommentsModel.needed_extra_diff_context())
         hide_whitespace_changes = False
         source_repo = pull_request_version.source_repo
         source_ref_id = pull_request_version.source_ref_parts.commit_id
         target_ref_id = pull_request_version.target_ref_parts.commit_id
         old_diff = self._get_diff_from_pr_or_version(
             source_repo, source_ref_id, target_ref_id,
             hide_whitespace_changes=hide_whitespace_changes, diff_context=diff_context)
 
         source_repo = pull_request.source_repo
         source_ref_id = pull_request.source_ref_parts.commit_id
         target_ref_id = pull_request.target_ref_parts.commit_id
 
         new_diff = self._get_diff_from_pr_or_version(
             source_repo, source_ref_id, target_ref_id,
             hide_whitespace_changes=hide_whitespace_changes, diff_context=diff_context)
 
         old_diff_data = diffs.DiffProcessor(old_diff)
         old_diff_data.prepare()
         new_diff_data = diffs.DiffProcessor(new_diff)
         new_diff_data.prepare()
 
         return old_diff_data, new_diff_data
 
     def _link_comments_to_version(self, pull_request_version):
         """
         Link all unlinked comments of this pull request to the given version.
 
         :param pull_request_version: The `PullRequestVersion` to which
             the comments shall be linked.
 
         """
         pull_request = pull_request_version.pull_request
         comments = ChangesetComment.query()\
             .filter(
                 # TODO: johbo: Should we query for the repo at all here?
                 # Pending decision on how comments of PRs are to be related
                 # to either the source repo, the target repo or no repo at all.
                 ChangesetComment.repo_id == pull_request.target_repo.repo_id,
                 ChangesetComment.pull_request == pull_request,
                 ChangesetComment.pull_request_version == None)\
             .order_by(ChangesetComment.comment_id.asc())
 
         # TODO: johbo: Find out why this breaks if it is done in a bulk
         # operation.
         for comment in comments:
             comment.pull_request_version_id = (
                 pull_request_version.pull_request_version_id)
             Session().add(comment)
 
     def _calculate_commit_id_changes(self, old_ids, new_ids):
         added = [x for x in new_ids if x not in old_ids]
         common = [x for x in new_ids if x in old_ids]
         removed = [x for x in old_ids if x not in new_ids]
         total = new_ids
         return ChangeTuple(added, common, removed, total)
 
     def _calculate_file_changes(self, old_diff_data, new_diff_data):
 
         old_files = OrderedDict()
         for diff_data in old_diff_data.parsed_diff:
             old_files[diff_data['filename']] = md5_safe(diff_data['raw_diff'])
 
         added_files = []
         modified_files = []
         removed_files = []
         for diff_data in new_diff_data.parsed_diff:
             new_filename = diff_data['filename']
             new_hash = md5_safe(diff_data['raw_diff'])
 
             old_hash = old_files.get(new_filename)
             if not old_hash:
                 # file is not present in old diff, means it's added
                 added_files.append(new_filename)
             else:
                 if new_hash != old_hash:
                     modified_files.append(new_filename)
                 # now remove a file from old, since we have seen it already
                 del old_files[new_filename]
 
         # removed files is when there are present in old, but not in NEW,
         # since we remove old files that are present in new diff, left-overs
         # if any should be the removed files
         removed_files.extend(old_files.keys())
 
         return FileChangeTuple(added_files, modified_files, removed_files)
 
     def _render_update_message(self, changes, file_changes):
         """
         render the message using DEFAULT_COMMENTS_RENDERER (RST renderer),
         so it's always looking the same disregarding on which default
         renderer system is using.
 
         :param changes: changes named tuple
         :param file_changes: file changes named tuple
 
         """
         new_status = ChangesetStatus.get_status_lbl(
             ChangesetStatus.STATUS_UNDER_REVIEW)
 
         changed_files = (
             file_changes.added + file_changes.modified + file_changes.removed)
 
         params = {
             'under_review_label': new_status,
             'added_commits': changes.added,
             'removed_commits': changes.removed,
             'changed_files': changed_files,
             'added_files': file_changes.added,
             'modified_files': file_changes.modified,
             'removed_files': file_changes.removed,
         }
         renderer = RstTemplateRenderer()
         return renderer.render('pull_request_update.mako', **params)
 
     def edit(self, pull_request, title, description, description_renderer, user):
         pull_request = self.__get_pull_request(pull_request)
         old_data = pull_request.get_api_data(with_merge_state=False)
         if pull_request.is_closed():
             raise ValueError('This pull request is closed')
         if title:
             pull_request.title = title
         pull_request.description = description
         pull_request.updated_on = datetime.datetime.now()
         pull_request.description_renderer = description_renderer
         Session().add(pull_request)
         self._log_audit_action(
             'repo.pull_request.edit', {'old_data': old_data},
             user, pull_request)
 
     def update_reviewers(self, pull_request, reviewer_data, user):
         """
         Update the reviewers in the pull request
 
         :param pull_request: the pr to update
         :param reviewer_data: list of tuples
             [(user, ['reason1', 'reason2'], mandatory_flag, [rules])]
         """
         pull_request = self.__get_pull_request(pull_request)
         if pull_request.is_closed():
             raise ValueError('This pull request is closed')
 
         reviewers = {}
         for user_id, reasons, mandatory, rules in reviewer_data:
             if isinstance(user_id, (int, basestring)):
                 user_id = self._get_user(user_id).user_id
             reviewers[user_id] = {
                 'reasons': reasons, 'mandatory': mandatory}
 
         reviewers_ids = set(reviewers.keys())
         current_reviewers = PullRequestReviewers.query()\
             .filter(PullRequestReviewers.pull_request ==
                     pull_request).all()
         current_reviewers_ids = set([x.user.user_id for x in current_reviewers])
 
         ids_to_add = reviewers_ids.difference(current_reviewers_ids)
         ids_to_remove = current_reviewers_ids.difference(reviewers_ids)
 
         log.debug("Adding %s reviewers", ids_to_add)
         log.debug("Removing %s reviewers", ids_to_remove)
         changed = False
         for uid in ids_to_add:
             changed = True
             _usr = self._get_user(uid)
             reviewer = PullRequestReviewers()
             reviewer.user = _usr
             reviewer.pull_request = pull_request
             reviewer.reasons = reviewers[uid]['reasons']
             # NOTE(marcink): mandatory shouldn't be changed now
             # reviewer.mandatory = reviewers[uid]['reasons']
             Session().add(reviewer)
             self._log_audit_action(
                 'repo.pull_request.reviewer.add', {'data': reviewer.get_dict()},
                 user, pull_request)
 
         for uid in ids_to_remove:
             changed = True
             reviewers = PullRequestReviewers.query()\
                 .filter(PullRequestReviewers.user_id == uid,
                         PullRequestReviewers.pull_request == pull_request)\
                 .all()
             # use .all() in case we accidentally added the same person twice
             # this CAN happen due to the lack of DB checks
             for obj in reviewers:
                 old_data = obj.get_dict()
                 Session().delete(obj)
                 self._log_audit_action(
                     'repo.pull_request.reviewer.delete',
                     {'old_data': old_data}, user, pull_request)
 
         if changed:
             pull_request.updated_on = datetime.datetime.now()
             Session().add(pull_request)
 
         self.notify_reviewers(pull_request, ids_to_add)
         return ids_to_add, ids_to_remove
 
     def get_url(self, pull_request, request=None, permalink=False):
         if not request:
             request = get_current_request()
 
         if permalink:
             return request.route_url(
                 'pull_requests_global',
                 pull_request_id=pull_request.pull_request_id,)
         else:
             return request.route_url('pullrequest_show',
                 repo_name=safe_str(pull_request.target_repo.repo_name),
                 pull_request_id=pull_request.pull_request_id,)
 
     def get_shadow_clone_url(self, pull_request, request=None):
         """
         Returns qualified url pointing to the shadow repository. If this pull
         request is closed there is no shadow repository and ``None`` will be
         returned.
         """
         if pull_request.is_closed():
             return None
         else:
             pr_url = urllib.unquote(self.get_url(pull_request, request=request))
             return safe_unicode('{pr_url}/repository'.format(pr_url=pr_url))
 
     def notify_reviewers(self, pull_request, reviewers_ids):
         # notification to reviewers
         if not reviewers_ids:
             return
 
         pull_request_obj = pull_request
         # get the current participants of this pull request
         recipients = reviewers_ids
         notification_type = EmailNotificationModel.TYPE_PULL_REQUEST
 
         pr_source_repo = pull_request_obj.source_repo
         pr_target_repo = pull_request_obj.target_repo
 
         pr_url = h.route_url('pullrequest_show',
             repo_name=pr_target_repo.repo_name,
             pull_request_id=pull_request_obj.pull_request_id,)
 
         # set some variables for email notification
         pr_target_repo_url = h.route_url(
             'repo_summary', repo_name=pr_target_repo.repo_name)
 
         pr_source_repo_url = h.route_url(
             'repo_summary', repo_name=pr_source_repo.repo_name)
 
         # pull request specifics
         pull_request_commits = [
             (x.raw_id, x.message)
             for x in map(pr_source_repo.get_commit, pull_request.revisions)]
 
         kwargs = {
             'user': pull_request.author,
             'pull_request': pull_request_obj,
             'pull_request_commits': pull_request_commits,
 
             'pull_request_target_repo': pr_target_repo,
             'pull_request_target_repo_url': pr_target_repo_url,
 
             'pull_request_source_repo': pr_source_repo,
             'pull_request_source_repo_url': pr_source_repo_url,
 
             'pull_request_url': pr_url,
         }
 
         # pre-generate the subject for notification itself
         (subject,
          _h, _e,  # we don't care about those
          body_plaintext) = EmailNotificationModel().render_email(
             notification_type, **kwargs)
 
         # create notification objects, and emails
         NotificationModel().create(
             created_by=pull_request.author,
             notification_subject=subject,
             notification_body=body_plaintext,
             notification_type=notification_type,
             recipients=recipients,
             email_kwargs=kwargs,
         )
 
     def delete(self, pull_request, user):
         pull_request = self.__get_pull_request(pull_request)
         old_data = pull_request.get_api_data(with_merge_state=False)
         self._cleanup_merge_workspace(pull_request)
         self._log_audit_action(
             'repo.pull_request.delete', {'old_data': old_data},
             user, pull_request)
         Session().delete(pull_request)
 
     def close_pull_request(self, pull_request, user):
         pull_request = self.__get_pull_request(pull_request)
         self._cleanup_merge_workspace(pull_request)
         pull_request.status = PullRequest.STATUS_CLOSED
         pull_request.updated_on = datetime.datetime.now()
         Session().add(pull_request)
         self._trigger_pull_request_hook(
             pull_request, pull_request.author, 'close')
 
         pr_data = pull_request.get_api_data(with_merge_state=False)
         self._log_audit_action(
             'repo.pull_request.close', {'data': pr_data}, user, pull_request)
 
     def close_pull_request_with_comment(
             self, pull_request, user, repo, message=None, auth_user=None):
 
         pull_request_review_status = pull_request.calculated_review_status()
 
         if pull_request_review_status == ChangesetStatus.STATUS_APPROVED:
             # approved only if we have voting consent
             status = ChangesetStatus.STATUS_APPROVED
         else:
             status = ChangesetStatus.STATUS_REJECTED
         status_lbl = ChangesetStatus.get_status_lbl(status)
 
         default_message = (
             'Closing with status change {transition_icon} {status}.'
         ).format(transition_icon='>', status=status_lbl)
         text = message or default_message
 
         # create a comment, and link it to new status
         comment = CommentsModel().create(
             text=text,
             repo=repo.repo_id,
             user=user.user_id,
             pull_request=pull_request.pull_request_id,
             status_change=status_lbl,
             status_change_type=status,
             closing_pr=True,
             auth_user=auth_user,
         )
 
         # calculate old status before we change it
         old_calculated_status = pull_request.calculated_review_status()
         ChangesetStatusModel().set_status(
             repo.repo_id,
             status,
             user.user_id,
             comment=comment,
             pull_request=pull_request.pull_request_id
         )
 
         Session().flush()
         events.trigger(events.PullRequestCommentEvent(pull_request, comment))
         # we now calculate the status of pull request again, and based on that
         # calculation trigger status change. This might happen in cases
         # that non-reviewer admin closes a pr, which means his vote doesn't
         # change the status, while if he's a reviewer this might change it.
         calculated_status = pull_request.calculated_review_status()
         if old_calculated_status != calculated_status:
             self._trigger_pull_request_hook(
                 pull_request, user, 'review_status_change')
 
         # finally close the PR
         PullRequestModel().close_pull_request(
             pull_request.pull_request_id, user)
 
         return comment, status
 
     def merge_status(self, pull_request, translator=None,
                      force_shadow_repo_refresh=False):
         _ = translator or get_current_request().translate
 
         if not self._is_merge_enabled(pull_request):
             return False, _('Server-side pull request merging is disabled.')
         if pull_request.is_closed():
             return False, _('This pull request is closed.')
         merge_possible, msg = self._check_repo_requirements(
             target=pull_request.target_repo, source=pull_request.source_repo,
             translator=_)
         if not merge_possible:
             return merge_possible, msg
 
         try:
             resp = self._try_merge(
                 pull_request,
                 force_shadow_repo_refresh=force_shadow_repo_refresh)
             log.debug("Merge response: %s", resp)
             status = resp.possible, self.merge_status_message(
                 resp.failure_reason)
         except NotImplementedError:
             status = False, _('Pull request merging is not supported.')
 
         return status
 
     def _check_repo_requirements(self, target, source, translator):
         """
         Check if `target` and `source` have compatible requirements.
 
         Currently this is just checking for largefiles.
         """
         _ = translator
         target_has_largefiles = self._has_largefiles(target)
         source_has_largefiles = self._has_largefiles(source)
         merge_possible = True
         message = u''
 
         if target_has_largefiles != source_has_largefiles:
             merge_possible = False
             if source_has_largefiles:
                 message = _(
                     'Target repository large files support is disabled.')
             else:
                 message = _(
                     'Source repository large files support is disabled.')
 
         return merge_possible, message
 
     def _has_largefiles(self, repo):
         largefiles_ui = VcsSettingsModel(repo=repo).get_ui_settings(
             'extensions', 'largefiles')
         return largefiles_ui and largefiles_ui[0].active
 
     def _try_merge(self, pull_request, force_shadow_repo_refresh=False):
         """
         Try to merge the pull request and return the merge status.
         """
         log.debug(
             "Trying out if the pull request %s can be merged. Force_refresh=%s",
             pull_request.pull_request_id, force_shadow_repo_refresh)
         target_vcs = pull_request.target_repo.scm_instance()
 
         # Refresh the target reference.
         try:
             target_ref = self._refresh_reference(
                 pull_request.target_ref_parts, target_vcs)
         except CommitDoesNotExistError:
             merge_state = MergeResponse(
                 False, False, None, MergeFailureReason.MISSING_TARGET_REF)
             return merge_state
 
         target_locked = pull_request.target_repo.locked
         if target_locked and target_locked[0]:
             log.debug("The target repository is locked.")
             merge_state = MergeResponse(
                 False, False, None, MergeFailureReason.TARGET_IS_LOCKED)
         elif force_shadow_repo_refresh or self._needs_merge_state_refresh(
                 pull_request, target_ref):
             log.debug("Refreshing the merge status of the repository.")
             merge_state = self._refresh_merge_state(
                 pull_request, target_vcs, target_ref)
         else:
             possible = pull_request.\
                 last_merge_status == MergeFailureReason.NONE
             merge_state = MergeResponse(
                 possible, False, None, pull_request.last_merge_status)
 
         return merge_state
 
     def _refresh_reference(self, reference, vcs_repository):
         if reference.type in self.UPDATABLE_REF_TYPES:
             name_or_id = reference.name
         else:
             name_or_id = reference.commit_id
         refreshed_commit = vcs_repository.get_commit(name_or_id)
         refreshed_reference = Reference(
             reference.type, reference.name, refreshed_commit.raw_id)
         return refreshed_reference
 
     def _needs_merge_state_refresh(self, pull_request, target_reference):
         return not(
             pull_request.revisions and
             pull_request.revisions[0] == pull_request._last_merge_source_rev and
             target_reference.commit_id == pull_request._last_merge_target_rev)
 
     def _refresh_merge_state(self, pull_request, target_vcs, target_reference):
         workspace_id = self._workspace_id(pull_request)
         source_vcs = pull_request.source_repo.scm_instance()
         repo_id = pull_request.target_repo.repo_id
         use_rebase = self._use_rebase_for_merging(pull_request)
         close_branch = self._close_branch_before_merging(pull_request)
         merge_state = target_vcs.merge(
             repo_id, workspace_id,
             target_reference, source_vcs, pull_request.source_ref_parts,
             dry_run=True, use_rebase=use_rebase,
             close_branch=close_branch)
 
         # Do not store the response if there was an unknown error.
         if merge_state.failure_reason != MergeFailureReason.UNKNOWN:
             pull_request._last_merge_source_rev = \
                 pull_request.source_ref_parts.commit_id
             pull_request._last_merge_target_rev = target_reference.commit_id
             pull_request.last_merge_status = merge_state.failure_reason
             pull_request.shadow_merge_ref = merge_state.merge_ref
             Session().add(pull_request)
             Session().commit()
 
         return merge_state
 
     def _workspace_id(self, pull_request):
         workspace_id = 'pr-%s' % pull_request.pull_request_id
         return workspace_id
 
     def merge_status_message(self, status_code):
         """
         Return a human friendly error message for the given merge status code.
         """
         return self.MERGE_STATUS_MESSAGES[status_code]
 
     def generate_repo_data(self, repo, commit_id=None, branch=None,
                            bookmark=None, translator=None):
         from rhodecode.model.repo import RepoModel
 
         all_refs, selected_ref = \
             self._get_repo_pullrequest_sources(
                 repo.scm_instance(), commit_id=commit_id,
                 branch=branch, bookmark=bookmark, translator=translator)
 
         refs_select2 = []
         for element in all_refs:
             children = [{'id': x[0], 'text': x[1]} for x in element[0]]
             refs_select2.append({'text': element[1], 'children': children})
 
         return {
             'user': {
                 'user_id': repo.user.user_id,
                 'username': repo.user.username,
                 'firstname': repo.user.first_name,
                 'lastname': repo.user.last_name,
                 'gravatar_link': h.gravatar_url(repo.user.email, 14),
             },
             'name': repo.repo_name,
             'link': RepoModel().get_url(repo),
             'description': h.chop_at_smart(repo.description_safe, '\n'),
             'refs': {
                 'all_refs': all_refs,
                 'selected_ref': selected_ref,
                 'select2_refs': refs_select2
             }
         }
 
     def generate_pullrequest_title(self, source, source_ref, target):
         return u'{source}#{at_ref} to {target}'.format(
             source=source,
             at_ref=source_ref,
             target=target,
         )
 
     def _cleanup_merge_workspace(self, pull_request):
         # Merging related cleanup
         repo_id = pull_request.target_repo.repo_id
         target_scm = pull_request.target_repo.scm_instance()
         workspace_id = self._workspace_id(pull_request)
 
         try:
             target_scm.cleanup_merge_workspace(repo_id, workspace_id)
         except NotImplementedError:
             pass
 
     def _get_repo_pullrequest_sources(
             self, repo, commit_id=None, branch=None, bookmark=None,
             translator=None):
         """
         Return a structure with repo's interesting commits, suitable for
         the selectors in pullrequest controller
 
         :param commit_id: a commit that must be in the list somehow
             and selected by default
         :param branch: a branch that must be in the list and selected
             by default - even if closed
         :param bookmark: a bookmark that must be in the list and selected
         """
         _ = translator or get_current_request().translate
 
         commit_id = safe_str(commit_id) if commit_id else None
         branch = safe_str(branch) if branch else None
         bookmark = safe_str(bookmark) if bookmark else None
 
         selected = None
 
         # order matters: first source that has commit_id in it will be selected
         sources = []
         sources.append(('book', repo.bookmarks.items(), _('Bookmarks'), bookmark))
         sources.append(('branch', repo.branches.items(), _('Branches'), branch))
 
         if commit_id:
             ref_commit = (h.short_id(commit_id), commit_id)
             sources.append(('rev', [ref_commit], _('Commit IDs'), commit_id))
 
         sources.append(
             ('branch', repo.branches_closed.items(), _('Closed Branches'), branch),
         )
 
         groups = []
         for group_key, ref_list, group_name, match in sources:
             group_refs = []
             for ref_name, ref_id in ref_list:
                 ref_key = '%s:%s:%s' % (group_key, ref_name, ref_id)
                 group_refs.append((ref_key, ref_name))
 
                 if not selected:
                     if set([commit_id, match]) & set([ref_id, ref_name]):
                         selected = ref_key
 
             if group_refs:
                 groups.append((group_refs, group_name))
 
         if not selected:
             ref = commit_id or branch or bookmark
             if ref:
                 raise CommitDoesNotExistError(
                     'No commit refs could be found matching: %s' % ref)
             elif repo.DEFAULT_BRANCH_NAME in repo.branches:
                 selected = 'branch:%s:%s' % (
                     repo.DEFAULT_BRANCH_NAME,
                     repo.branches[repo.DEFAULT_BRANCH_NAME]
                 )
             elif repo.commit_ids:
                 # make the user select in this case
                 selected = None
             else:
                 raise EmptyRepositoryError()
         return groups, selected
 
     def get_diff(self, source_repo, source_ref_id, target_ref_id,
                  hide_whitespace_changes, diff_context):
 
         return self._get_diff_from_pr_or_version(
             source_repo, source_ref_id, target_ref_id,
             hide_whitespace_changes=hide_whitespace_changes, diff_context=diff_context)
 
     def _get_diff_from_pr_or_version(
             self, source_repo, source_ref_id, target_ref_id,
             hide_whitespace_changes, diff_context):
 
         target_commit = source_repo.get_commit(
             commit_id=safe_str(target_ref_id))
         source_commit = source_repo.get_commit(
             commit_id=safe_str(source_ref_id))
         if isinstance(source_repo, Repository):
             vcs_repo = source_repo.scm_instance()
         else:
             vcs_repo = source_repo
 
         # TODO: johbo: In the context of an update, we cannot reach
         # the old commit anymore with our normal mechanisms. It needs
         # some sort of special support in the vcs layer to avoid this
         # workaround.
         if (source_commit.raw_id == vcs_repo.EMPTY_COMMIT_ID and
                 vcs_repo.alias == 'git'):
             source_commit.raw_id = safe_str(source_ref_id)
 
         log.debug('calculating diff between '
                   'source_ref:%s and target_ref:%s for repo `%s`',
                   target_ref_id, source_ref_id,
                   safe_unicode(vcs_repo.path))
 
         vcs_diff = vcs_repo.get_diff(
             commit1=target_commit, commit2=source_commit,
             ignore_whitespace=hide_whitespace_changes, context=diff_context)
         return vcs_diff
 
     def _is_merge_enabled(self, pull_request):
         return self._get_general_setting(
             pull_request, 'rhodecode_pr_merge_enabled')
 
     def _use_rebase_for_merging(self, pull_request):
         repo_type = pull_request.target_repo.repo_type
         if repo_type == 'hg':
             return self._get_general_setting(
                 pull_request, 'rhodecode_hg_use_rebase_for_merging')
         elif repo_type == 'git':
             return self._get_general_setting(
                 pull_request, 'rhodecode_git_use_rebase_for_merging')
 
         return False
 
     def _close_branch_before_merging(self, pull_request):
         repo_type = pull_request.target_repo.repo_type
         if repo_type == 'hg':
             return self._get_general_setting(
                 pull_request, 'rhodecode_hg_close_branch_before_merging')
         elif repo_type == 'git':
             return self._get_general_setting(
                 pull_request, 'rhodecode_git_close_branch_before_merging')
 
         return False
 
     def _get_general_setting(self, pull_request, settings_key, default=False):
         settings_model = VcsSettingsModel(repo=pull_request.target_repo)
         settings = settings_model.get_general_settings()
         return settings.get(settings_key, default)
 
     def _log_audit_action(self, action, action_data, user, pull_request):
         audit_logger.store(
             action=action,
             action_data=action_data,
             user=user,
             repo=pull_request.target_repo)
 
     def get_reviewer_functions(self):
         """
         Fetches functions for validation and fetching default reviewers.
         If available we use the EE package, else we fallback to CE
         package functions
         """
         try:
             from rc_reviewers.utils import get_default_reviewers_data
             from rc_reviewers.utils import validate_default_reviewers
         except ImportError:
             from rhodecode.apps.repository.utils import get_default_reviewers_data
             from rhodecode.apps.repository.utils import validate_default_reviewers
 
         return get_default_reviewers_data, validate_default_reviewers
 
 
 class MergeCheck(object):
     """
     Perform Merge Checks and returns a check object which stores information
     about merge errors, and merge conditions
     """
     TODO_CHECK = 'todo'
     PERM_CHECK = 'perm'
     REVIEW_CHECK = 'review'
     MERGE_CHECK = 'merge'
 
     def __init__(self):
         self.review_status = None
         self.merge_possible = None
         self.merge_msg = ''
         self.failed = None
         self.errors = []
         self.error_details = OrderedDict()
 
     def push_error(self, error_type, message, error_key, details):
         self.failed = True
         self.errors.append([error_type, message])
         self.error_details[error_key] = dict(
             details=details,
             error_type=error_type,
             message=message
         )
 
     @classmethod
     def validate(cls, pull_request, auth_user, translator, fail_early=False,
                  force_shadow_repo_refresh=False):
         _ = translator
         merge_check = cls()
 
         # permissions to merge
         user_allowed_to_merge = PullRequestModel().check_user_merge(
             pull_request, auth_user)
         if not user_allowed_to_merge:
             log.debug("MergeCheck: cannot merge, approval is pending.")
 
             msg = _('User `{}` not allowed to perform merge.').format(auth_user.username)
             merge_check.push_error('error', msg, cls.PERM_CHECK, auth_user.username)
             if fail_early:
                 return merge_check
 
         # permission to merge into the target branch
         target_commit_id = pull_request.target_ref_parts.commit_id
         if pull_request.target_ref_parts.type == 'branch':
             branch_name = pull_request.target_ref_parts.name
         else:
             # for mercurial we can always figure out the branch from the commit
             # in case of bookmark
             target_commit = pull_request.target_repo.get_commit(target_commit_id)
             branch_name = target_commit.branch
 
         rule, branch_perm = auth_user.get_rule_and_branch_permission(
             pull_request.target_repo.repo_name, branch_name)
         if branch_perm and branch_perm == 'branch.none':
             msg = _('Target branch `{}` changes rejected by rule {}.').format(
                 branch_name, rule)
             merge_check.push_error('error', msg, cls.PERM_CHECK, auth_user.username)
             if fail_early:
                 return merge_check
 
         # review status, must be always present
         review_status = pull_request.calculated_review_status()
         merge_check.review_status = review_status
 
         status_approved = review_status == ChangesetStatus.STATUS_APPROVED
         if not status_approved:
             log.debug("MergeCheck: cannot merge, approval is pending.")
 
             msg = _('Pull request reviewer approval is pending.')
 
             merge_check.push_error(
                 'warning', msg, cls.REVIEW_CHECK, review_status)
 
             if fail_early:
                 return merge_check
 
         # left over TODOs
         todos = CommentsModel().get_unresolved_todos(pull_request)
         if todos:
             log.debug("MergeCheck: cannot merge, {} "
                       "unresolved todos left.".format(len(todos)))
 
             if len(todos) == 1:
                 msg = _('Cannot merge, {} TODO still not resolved.').format(
                     len(todos))
             else:
                 msg = _('Cannot merge, {} TODOs still not resolved.').format(
                     len(todos))
 
             merge_check.push_error('warning', msg, cls.TODO_CHECK, todos)
 
             if fail_early:
                 return merge_check
 
         # merge possible, here is the filesystem simulation + shadow repo
         merge_status, msg = PullRequestModel().merge_status(
             pull_request, translator=translator,
             force_shadow_repo_refresh=force_shadow_repo_refresh)
         merge_check.merge_possible = merge_status
         merge_check.merge_msg = msg
         if not merge_status:
             log.debug(
                 "MergeCheck: cannot merge, pull request merge not possible.")
             merge_check.push_error('warning', msg, cls.MERGE_CHECK, None)
 
             if fail_early:
                 return merge_check
 
         log.debug('MergeCheck: is failed: %s', merge_check.failed)
         return merge_check
 
     @classmethod
     def get_merge_conditions(cls, pull_request, translator):
         _ = translator
         merge_details = {}
 
         model = PullRequestModel()
         use_rebase = model._use_rebase_for_merging(pull_request)
 
         if use_rebase:
             merge_details['merge_strategy'] = dict(
                 details={},
                 message=_('Merge strategy: rebase')
             )
         else:
             merge_details['merge_strategy'] = dict(
                 details={},
                 message=_('Merge strategy: explicit merge commit')
             )
 
         close_branch = model._close_branch_before_merging(pull_request)
         if close_branch:
             repo_type = pull_request.target_repo.repo_type
             if repo_type == 'hg':
                 close_msg = _('Source branch will be closed after merge.')
             elif repo_type == 'git':
                 close_msg = _('Source branch will be deleted after merge.')
 
             merge_details['close_branch'] = dict(
                 details={},
                 message=close_msg
             )
 
         return merge_details
 
 ChangeTuple = collections.namedtuple(
     'ChangeTuple', ['added', 'common', 'removed', 'total'])
 
 FileChangeTuple = collections.namedtuple(
     'FileChangeTuple', ['added', 'modified', 'removed'])