pull-requests: change the update commits logic to handle target changes better.

- references  #5266
- don't create comments if NO changes in PR were detected, but target changed
- Show the origin of changes target/source repos
- Allows updating the diffs without invalidating voting and creating new versions.

rhodecode/controllers/pullrequests.py

@@ -1,1071 +1,1083 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2012-2017 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 requests controller for rhodecode for initializing pull requests
 """
 import types
 
 import peppercorn
 import formencode
 import logging
 import collections
 
 from webob.exc import HTTPNotFound, HTTPForbidden, HTTPBadRequest
 from pylons import request, tmpl_context as c, url
 from pylons.controllers.util import redirect
 from pylons.i18n.translation import _
 from pyramid.threadlocal import get_current_registry
 from sqlalchemy.sql import func
 from sqlalchemy.sql.expression import or_
 
 from rhodecode import events
 from rhodecode.lib import auth, diffs, helpers as h, codeblocks
 from rhodecode.lib.ext_json import json
 from rhodecode.lib.base import (
     BaseRepoController, render, vcs_operation_context)
 from rhodecode.lib.auth import (
     LoginRequired, HasRepoPermissionAnyDecorator, NotAnonymous,
     HasAcceptedRepoType, XHRRequired)
 from rhodecode.lib.channelstream import channelstream_request
 from rhodecode.lib.utils import jsonify
 from rhodecode.lib.utils2 import (
     safe_int, safe_str, str2bool, safe_unicode)
 from rhodecode.lib.vcs.backends.base import (
     EmptyCommit, UpdateFailureReason, EmptyRepository)
 from rhodecode.lib.vcs.exceptions import (
     EmptyRepositoryError, CommitDoesNotExistError, RepositoryRequirementError,
     NodeDoesNotExistError)
 
 from rhodecode.model.changeset_status import ChangesetStatusModel
 from rhodecode.model.comment import CommentsModel
 from rhodecode.model.db import (PullRequest, ChangesetStatus, ChangesetComment,
     Repository, PullRequestVersion)
 from rhodecode.model.forms import PullRequestForm
 from rhodecode.model.meta import Session
 from rhodecode.model.pull_request import PullRequestModel, MergeCheck
 
 log = logging.getLogger(__name__)
 
 
 class PullrequestsController(BaseRepoController):
 
     def __before__(self):
         super(PullrequestsController, self).__before__()
         c.REVIEW_STATUS_APPROVED = ChangesetStatus.STATUS_APPROVED
         c.REVIEW_STATUS_REJECTED = ChangesetStatus.STATUS_REJECTED
 
     def _extract_ordering(self, request):
         column_index = safe_int(request.GET.get('order[0][column]'))
         order_dir = request.GET.get('order[0][dir]', 'desc')
         order_by = request.GET.get(
             'columns[%s][data][sort]' % column_index, 'name_raw')
         return order_by, order_dir
 
     @LoginRequired()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     @HasAcceptedRepoType('git', 'hg')
     def show_all(self, repo_name):
         # filter types
         c.active = 'open'
         c.source = str2bool(request.GET.get('source'))
         c.closed = str2bool(request.GET.get('closed'))
         c.my = str2bool(request.GET.get('my'))
         c.awaiting_review = str2bool(request.GET.get('awaiting_review'))
         c.awaiting_my_review = str2bool(request.GET.get('awaiting_my_review'))
         c.repo_name = repo_name
 
         opened_by = None
         if c.my:
             c.active = 'my'
             opened_by = [c.rhodecode_user.user_id]
 
         statuses = [PullRequest.STATUS_NEW, PullRequest.STATUS_OPEN]
         if c.closed:
             c.active = 'closed'
             statuses = [PullRequest.STATUS_CLOSED]
 
         if c.awaiting_review and not c.source:
             c.active = 'awaiting'
         if c.source and not c.awaiting_review:
             c.active = 'source'
         if c.awaiting_my_review:
             c.active = 'awaiting_my'
 
         data = self._get_pull_requests_list(
             repo_name=repo_name, opened_by=opened_by, statuses=statuses)
         if not request.is_xhr:
             c.data = json.dumps(data['data'])
             c.records_total = data['recordsTotal']
             return render('/pullrequests/pullrequests.mako')
         else:
             return json.dumps(data)
 
     def _get_pull_requests_list(self, repo_name, opened_by, statuses):
         # pagination
         start = safe_int(request.GET.get('start'), 0)
         length = safe_int(request.GET.get('length'), c.visual.dashboard_items)
         order_by, order_dir = self._extract_ordering(request)
 
         if c.awaiting_review:
             pull_requests = PullRequestModel().get_awaiting_review(
                 repo_name, source=c.source, opened_by=opened_by,
                 statuses=statuses, offset=start, length=length,
                 order_by=order_by, order_dir=order_dir)
             pull_requests_total_count = PullRequestModel(
             ).count_awaiting_review(
                 repo_name, source=c.source, statuses=statuses,
                 opened_by=opened_by)
         elif c.awaiting_my_review:
             pull_requests = PullRequestModel().get_awaiting_my_review(
                 repo_name, source=c.source, opened_by=opened_by,
                 user_id=c.rhodecode_user.user_id, statuses=statuses,
                 offset=start, length=length, order_by=order_by,
                 order_dir=order_dir)
             pull_requests_total_count = PullRequestModel(
             ).count_awaiting_my_review(
                 repo_name, source=c.source, user_id=c.rhodecode_user.user_id,
                 statuses=statuses, opened_by=opened_by)
         else:
             pull_requests = PullRequestModel().get_all(
                 repo_name, source=c.source, opened_by=opened_by,
                 statuses=statuses, offset=start, length=length,
                 order_by=order_by, order_dir=order_dir)
             pull_requests_total_count = PullRequestModel().count_all(
                 repo_name, source=c.source, statuses=statuses,
                 opened_by=opened_by)
 
         from rhodecode.lib.utils import PartialRenderer
         _render = PartialRenderer('data_table/_dt_elements.mako')
         data = []
         for pr in pull_requests:
             comments = CommentsModel().get_all_comments(
                 c.rhodecode_db_repo.repo_id, pull_request=pr)
 
             data.append({
                 'name': _render('pullrequest_name',
                                 pr.pull_request_id, pr.target_repo.repo_name),
                 'name_raw': pr.pull_request_id,
                 'status': _render('pullrequest_status',
                                   pr.calculated_review_status()),
                 'title': _render(
                     'pullrequest_title', pr.title, pr.description),
                 'description': h.escape(pr.description),
                 'updated_on': _render('pullrequest_updated_on',
                                       h.datetime_to_time(pr.updated_on)),
                 'updated_on_raw': h.datetime_to_time(pr.updated_on),
                 'created_on': _render('pullrequest_updated_on',
                                       h.datetime_to_time(pr.created_on)),
                 'created_on_raw': h.datetime_to_time(pr.created_on),
                 'author': _render('pullrequest_author',
                                   pr.author.full_contact, ),
                 'author_raw': pr.author.full_name,
                 'comments': _render('pullrequest_comments', len(comments)),
                 'comments_raw': len(comments),
                 'closed': pr.is_closed(),
             })
         # json used to render the grid
         data = ({
             'data': data,
             'recordsTotal': pull_requests_total_count,
             'recordsFiltered': pull_requests_total_count,
         })
         return data
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     @HasAcceptedRepoType('git', 'hg')
     def index(self):
         source_repo = c.rhodecode_db_repo
 
         try:
             source_repo.scm_instance().get_commit()
         except EmptyRepositoryError:
             h.flash(h.literal(_('There are no commits yet')),
                     category='warning')
             redirect(url('summary_home', repo_name=source_repo.repo_name))
 
         commit_id = request.GET.get('commit')
         branch_ref = request.GET.get('branch')
         bookmark_ref = request.GET.get('bookmark')
 
         try:
             source_repo_data = PullRequestModel().generate_repo_data(
                 source_repo, commit_id=commit_id,
                 branch=branch_ref, bookmark=bookmark_ref)
         except CommitDoesNotExistError as e:
             log.exception(e)
             h.flash(_('Commit does not exist'), 'error')
             redirect(url('pullrequest_home', repo_name=source_repo.repo_name))
 
         default_target_repo = source_repo
 
         if source_repo.parent:
             parent_vcs_obj = source_repo.parent.scm_instance()
             if parent_vcs_obj and not parent_vcs_obj.is_empty():
                 # change default if we have a parent repo
                 default_target_repo = source_repo.parent
 
         target_repo_data = PullRequestModel().generate_repo_data(
             default_target_repo)
 
         selected_source_ref = source_repo_data['refs']['selected_ref']
 
         title_source_ref = selected_source_ref.split(':', 2)[1]
         c.default_title = PullRequestModel().generate_pullrequest_title(
             source=source_repo.repo_name,
             source_ref=title_source_ref,
             target=default_target_repo.repo_name
         )
 
         c.default_repo_data = {
             'source_repo_name': source_repo.repo_name,
             'source_refs_json': json.dumps(source_repo_data),
             'target_repo_name': default_target_repo.repo_name,
             'target_refs_json': json.dumps(target_repo_data),
         }
         c.default_source_ref = selected_source_ref
 
         return render('/pullrequests/pullrequest.mako')
 
     @LoginRequired()
     @NotAnonymous()
     @XHRRequired()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     @jsonify
     def get_repo_refs(self, repo_name, target_repo_name):
         repo = Repository.get_by_repo_name(target_repo_name)
         if not repo:
             raise HTTPNotFound
         return PullRequestModel().generate_repo_data(repo)
 
     @LoginRequired()
     @NotAnonymous()
     @XHRRequired()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     @jsonify
     def get_repo_destinations(self, repo_name):
         repo = Repository.get_by_repo_name(repo_name)
         if not repo:
             raise HTTPNotFound
         filter_query = request.GET.get('query')
 
         query = Repository.query() \
             .order_by(func.length(Repository.repo_name)) \
             .filter(or_(
             Repository.repo_name == repo.repo_name,
             Repository.fork_id == repo.repo_id))
 
         if filter_query:
             ilike_expression = u'%{}%'.format(safe_unicode(filter_query))
             query = query.filter(
                 Repository.repo_name.ilike(ilike_expression))
 
         add_parent = False
         if repo.parent:
             if filter_query in repo.parent.repo_name:
                 parent_vcs_obj = repo.parent.scm_instance()
                 if parent_vcs_obj and not parent_vcs_obj.is_empty():
                     add_parent = True
 
         limit = 20 - 1 if add_parent else 20
         all_repos = query.limit(limit).all()
         if add_parent:
             all_repos += [repo.parent]
 
         repos = []
         for obj in self.scm_model.get_repos(all_repos):
             repos.append({
                 'id': obj['name'],
                 'text': obj['name'],
                 'type': 'repo',
                 'obj': obj['dbrepo']
             })
 
         data = {
             'more': False,
             'results': [{
                 'text': _('Repositories'),
                 'children': repos
             }] if repos else []
         }
         return data
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     @HasAcceptedRepoType('git', 'hg')
     @auth.CSRFRequired()
     def create(self, repo_name):
         repo = Repository.get_by_repo_name(repo_name)
         if not repo:
             raise HTTPNotFound
 
         controls = peppercorn.parse(request.POST.items())
 
         try:
             _form = PullRequestForm(repo.repo_id)().to_python(controls)
         except formencode.Invalid as errors:
             if errors.error_dict.get('revisions'):
                 msg = 'Revisions: %s' % errors.error_dict['revisions']
             elif errors.error_dict.get('pullrequest_title'):
                 msg = _('Pull request requires a title with min. 3 chars')
             else:
                 msg = _('Error creating pull request: {}').format(errors)
             log.exception(msg)
             h.flash(msg, 'error')
 
             # would rather just go back to form ...
             return redirect(url('pullrequest_home', repo_name=repo_name))
 
         source_repo = _form['source_repo']
         source_ref = _form['source_ref']
         target_repo = _form['target_repo']
         target_ref = _form['target_ref']
         commit_ids = _form['revisions'][::-1]
         reviewers = [
             (r['user_id'], r['reasons']) for r in _form['review_members']]
 
         # find the ancestor for this pr
         source_db_repo = Repository.get_by_repo_name(_form['source_repo'])
         target_db_repo = Repository.get_by_repo_name(_form['target_repo'])
 
         source_scm = source_db_repo.scm_instance()
         target_scm = target_db_repo.scm_instance()
 
         source_commit = source_scm.get_commit(source_ref.split(':')[-1])
         target_commit = target_scm.get_commit(target_ref.split(':')[-1])
 
         ancestor = source_scm.get_common_ancestor(
             source_commit.raw_id, target_commit.raw_id, target_scm)
 
         target_ref_type, target_ref_name, __ = _form['target_ref'].split(':')
         target_ref = ':'.join((target_ref_type, target_ref_name, ancestor))
 
         pullrequest_title = _form['pullrequest_title']
         title_source_ref = source_ref.split(':', 2)[1]
         if not pullrequest_title:
             pullrequest_title = PullRequestModel().generate_pullrequest_title(
                 source=source_repo,
                 source_ref=title_source_ref,
                 target=target_repo
             )
 
         description = _form['pullrequest_desc']
         try:
             pull_request = PullRequestModel().create(
                 c.rhodecode_user.user_id, source_repo, source_ref, target_repo,
                 target_ref, commit_ids, reviewers, pullrequest_title,
                 description
             )
             Session().commit()
             h.flash(_('Successfully opened new pull request'),
                     category='success')
         except Exception as e:
             msg = _('Error occurred during sending pull request')
             log.exception(msg)
             h.flash(msg, category='error')
             return redirect(url('pullrequest_home', repo_name=repo_name))
 
         return redirect(url('pullrequest_show', repo_name=target_repo,
                             pull_request_id=pull_request.pull_request_id))
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     @auth.CSRFRequired()
     @jsonify
     def update(self, repo_name, pull_request_id):
         pull_request_id = safe_int(pull_request_id)
         pull_request = PullRequest.get_or_404(pull_request_id)
         # only owner or admin can update it
         allowed_to_update = PullRequestModel().check_user_update(
             pull_request, c.rhodecode_user)
         if allowed_to_update:
             controls = peppercorn.parse(request.POST.items())
 
             if 'review_members' in controls:
                 self._update_reviewers(
                     pull_request_id, controls['review_members'])
             elif str2bool(request.POST.get('update_commits', 'false')):
                 self._update_commits(pull_request)
             elif str2bool(request.POST.get('close_pull_request', 'false')):
                 self._reject_close(pull_request)
             elif str2bool(request.POST.get('edit_pull_request', 'false')):
                 self._edit_pull_request(pull_request)
             else:
                 raise HTTPBadRequest()
             return True
         raise HTTPForbidden()
 
     def _edit_pull_request(self, pull_request):
         try:
             PullRequestModel().edit(
                 pull_request, request.POST.get('title'),
                 request.POST.get('description'))
         except ValueError:
             msg = _(u'Cannot update closed pull requests.')
             h.flash(msg, category='error')
             return
         else:
             Session().commit()
 
         msg = _(u'Pull request title & description updated.')
         h.flash(msg, category='success')
         return
 
     def _update_commits(self, pull_request):
         resp = PullRequestModel().update_commits(pull_request)
 
         if resp.executed:
+
+            if resp.target_changed and resp.source_changed:
+                changed = 'target and source repositories'
+            elif resp.target_changed and not resp.source_changed:
+                changed = 'target repository'
+            elif not resp.target_changed and resp.source_changed:
+                changed = 'source repository'
+            else:
+                changed = 'nothing'
+
             msg = _(
                 u'Pull request updated to "{source_commit_id}" with '
-                u'{count_added} added, {count_removed} removed commits.')
+                u'{count_added} added, {count_removed} removed commits. '
+                u'Source of changes: {change_source}')
             msg = msg.format(
                 source_commit_id=pull_request.source_ref_parts.commit_id,
                 count_added=len(resp.changes.added),
-                count_removed=len(resp.changes.removed))
+                count_removed=len(resp.changes.removed),
+                change_source=changed)
             h.flash(msg, category='success')
 
             registry = get_current_registry()
             rhodecode_plugins = getattr(registry, 'rhodecode_plugins', {})
             channelstream_config = rhodecode_plugins.get('channelstream', {})
             if channelstream_config.get('enabled'):
                 message = msg + (
                     ' - <a onclick="window.location.reload()">'
                     '<strong>{}</strong></a>'.format(_('Reload page')))
                 channel = '/repo${}$/pr/{}'.format(
                     pull_request.target_repo.repo_name,
                     pull_request.pull_request_id
                 )
                 payload = {
                     'type': 'message',
                     'user': 'system',
                     'exclude_users': [request.user.username],
                     'channel': channel,
                     'message': {
                         'message': message,
                         'level': 'success',
                         'topic': '/notifications'
                     }
                 }
                 channelstream_request(
                     channelstream_config, [payload], '/message',
                     raise_exc=False)
         else:
             msg = PullRequestModel.UPDATE_STATUS_MESSAGES[resp.reason]
             warning_reasons = [
                 UpdateFailureReason.NO_CHANGE,
                 UpdateFailureReason.WRONG_REF_TPYE,
             ]
             category = 'warning' if resp.reason in warning_reasons else 'error'
             h.flash(msg, category=category)
 
     @auth.CSRFRequired()
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     def merge(self, repo_name, pull_request_id):
         """
         POST /{repo_name}/pull-request/{pull_request_id}
 
         Merge will perform a server-side merge of the specified
         pull request, if the pull request is approved and mergeable.
         After successful merging, the pull request is automatically
         closed, with a relevant comment.
         """
         pull_request_id = safe_int(pull_request_id)
         pull_request = PullRequest.get_or_404(pull_request_id)
         user = c.rhodecode_user
 
         check = MergeCheck.validate(pull_request, user)
         merge_possible = not check.failed
 
         for err_type, error_msg in check.errors:
             h.flash(error_msg, category=err_type)
 
         if merge_possible:
             log.debug("Pre-conditions checked, trying to merge.")
             extras = vcs_operation_context(
                 request.environ, repo_name=pull_request.target_repo.repo_name,
                 username=user.username, action='push',
                 scm=pull_request.target_repo.repo_type)
             self._merge_pull_request(pull_request, user, extras)
 
         return redirect(url(
             'pullrequest_show',
             repo_name=pull_request.target_repo.repo_name,
             pull_request_id=pull_request.pull_request_id))
 
     def _merge_pull_request(self, pull_request, user, extras):
         merge_resp = PullRequestModel().merge(
             pull_request, user, extras=extras)
 
         if merge_resp.executed:
             log.debug("The merge was successful, closing the pull request.")
             PullRequestModel().close_pull_request(
                 pull_request.pull_request_id, user)
             Session().commit()
             msg = _('Pull request was successfully merged and closed.')
             h.flash(msg, category='success')
         else:
             log.debug(
                 "The merge was not successful. Merge response: %s",
                 merge_resp)
             msg = PullRequestModel().merge_status_message(
                 merge_resp.failure_reason)
             h.flash(msg, category='error')
 
     def _update_reviewers(self, pull_request_id, review_members):
         reviewers = [
             (int(r['user_id']), r['reasons']) for r in review_members]
         PullRequestModel().update_reviewers(pull_request_id, reviewers)
         Session().commit()
 
     def _reject_close(self, pull_request):
         if pull_request.is_closed():
             raise HTTPForbidden()
 
         PullRequestModel().close_pull_request_with_comment(
             pull_request, c.rhodecode_user, c.rhodecode_db_repo)
         Session().commit()
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     @auth.CSRFRequired()
     @jsonify
     def delete(self, repo_name, pull_request_id):
         pull_request_id = safe_int(pull_request_id)
         pull_request = PullRequest.get_or_404(pull_request_id)
         # only owner can delete it !
         if pull_request.author.user_id == c.rhodecode_user.user_id:
             PullRequestModel().delete(pull_request)
             Session().commit()
             h.flash(_('Successfully deleted pull request'),
                     category='success')
             return redirect(url('my_account_pullrequests'))
         raise HTTPForbidden()
 
     def _get_pr_version(self, pull_request_id, version=None):
         pull_request_id = safe_int(pull_request_id)
         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 _get_diffset(
             self, source_repo, source_ref_id, target_ref_id, target_commit,
             source_commit, diff_limit, file_limit, display_inline_comments):
         vcs_diff = PullRequestModel().get_diff(
             source_repo, source_ref_id, target_ref_id)
 
         diff_processor = diffs.DiffProcessor(
             vcs_diff, format='newdiff', diff_limit=diff_limit,
             file_limit=file_limit, show_full_diff=c.fulldiff)
 
         _parsed = diff_processor.prepare()
 
         def _node_getter(commit):
             def get_node(fname):
                 try:
                     return commit.get_node(fname)
                 except NodeDoesNotExistError:
                     return None
 
             return get_node
 
         diffset = codeblocks.DiffSet(
             repo_name=c.repo_name,
             source_repo_name=c.source_repo.repo_name,
             source_node_getter=_node_getter(target_commit),
             target_node_getter=_node_getter(source_commit),
             comments=display_inline_comments
         )
         diffset = diffset.render_patchset(
             _parsed, target_commit.raw_id, source_commit.raw_id)
 
         return diffset
 
     @LoginRequired()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     def show(self, repo_name, pull_request_id):
         pull_request_id = safe_int(pull_request_id)
         version = request.GET.get('version')
         from_version = request.GET.get('from_version') or version
         merge_checks = request.GET.get('merge_checks')
         c.fulldiff = str2bool(request.GET.get('fulldiff'))
 
         (pull_request_latest,
          pull_request_at_ver,
          pull_request_display_obj,
          at_version) = self._get_pr_version(
             pull_request_id, version=version)
         pr_closed = pull_request_latest.is_closed()
 
         if pr_closed and (version or from_version):
             # not allow to browse versions
             return redirect(h.url('pullrequest_show', repo_name=repo_name,
                                   pull_request_id=pull_request_id))
 
         versions = pull_request_display_obj.versions()
 
         c.at_version = at_version
         c.at_version_num = (at_version
                             if at_version and at_version != 'latest'
                             else None)
         c.at_version_pos = ChangesetComment.get_index_from_version(
             c.at_version_num, versions)
 
         (prev_pull_request_latest,
          prev_pull_request_at_ver,
          prev_pull_request_display_obj,
          prev_at_version) = self._get_pr_version(
             pull_request_id, version=from_version)
 
         c.from_version = prev_at_version
         c.from_version_num = (prev_at_version
                               if prev_at_version and prev_at_version != 'latest'
                               else None)
         c.from_version_pos = ChangesetComment.get_index_from_version(
             c.from_version_num, versions)
 
         # define if we're in COMPARE mode or VIEW at version mode
         compare = at_version != prev_at_version
 
         # pull_requests repo_name we opened it against
         # ie. target_repo must match
         if repo_name != pull_request_at_ver.target_repo.repo_name:
             raise HTTPNotFound
 
         c.shadow_clone_url = PullRequestModel().get_shadow_clone_url(
             pull_request_at_ver)
 
         c.pull_request = pull_request_display_obj
         c.pull_request_latest = pull_request_latest
 
         if compare or (at_version and not at_version == 'latest'):
             c.allowed_to_change_status = False
             c.allowed_to_update = False
             c.allowed_to_merge = False
             c.allowed_to_delete = False
             c.allowed_to_comment = False
             c.allowed_to_close = False
         else:
             c.allowed_to_change_status = PullRequestModel(). \
                 check_user_change_status(pull_request_at_ver, c.rhodecode_user) \
                                          and not pr_closed
 
             c.allowed_to_update = PullRequestModel().check_user_update(
                 pull_request_latest, c.rhodecode_user) and not pr_closed
             c.allowed_to_merge = PullRequestModel().check_user_merge(
                 pull_request_latest, c.rhodecode_user) and not pr_closed
             c.allowed_to_delete = PullRequestModel().check_user_delete(
                 pull_request_latest, c.rhodecode_user) and not pr_closed
             c.allowed_to_comment = not pr_closed
             c.allowed_to_close = c.allowed_to_change_status and not pr_closed
 
         # check merge capabilities
         _merge_check = MergeCheck.validate(
             pull_request_latest, user=c.rhodecode_user)
         c.pr_merge_errors = _merge_check.error_details
         c.pr_merge_possible = not _merge_check.failed
         c.pr_merge_message = _merge_check.merge_msg
 
         c.pull_request_review_status = _merge_check.review_status
         if merge_checks:
             return render('/pullrequests/pullrequest_merge_checks.mako')
 
         comments_model = CommentsModel()
 
         # reviewers and statuses
         c.pull_request_reviewers = pull_request_at_ver.reviewers_statuses()
         allowed_reviewers = [x[0].user_id for x in c.pull_request_reviewers]
 
         # GENERAL COMMENTS with versions #
         q = comments_model._all_general_comments_of_pull_request(pull_request_latest)
         q = q.order_by(ChangesetComment.comment_id.asc())
         general_comments = q.order_by(ChangesetComment.pull_request_version_id.asc())
 
         # pick comments we want to render at current version
         c.comment_versions = comments_model.aggregate_comments(
             general_comments, versions, c.at_version_num)
         c.comments = c.comment_versions[c.at_version_num]['until']
 
         # INLINE COMMENTS with versions  #
         q = comments_model._all_inline_comments_of_pull_request(pull_request_latest)
         q = q.order_by(ChangesetComment.comment_id.asc())
         inline_comments = q.order_by(ChangesetComment.pull_request_version_id.asc())
         c.inline_versions = comments_model.aggregate_comments(
             inline_comments, versions, c.at_version_num, inline=True)
 
         # inject latest version
         latest_ver = PullRequest.get_pr_display_object(
             pull_request_latest, pull_request_latest)
 
         c.versions = versions + [latest_ver]
 
         # if we use version, then do not show later comments
         # than current version
         display_inline_comments = collections.defaultdict(
             lambda: collections.defaultdict(list))
         for co in inline_comments:
             if c.at_version_num:
                 # pick comments that are at least UPTO given version, so we
                 # don't render comments for higher version
                 should_render = co.pull_request_version_id and \
                                 co.pull_request_version_id <= c.at_version_num
             else:
                 # showing all, for 'latest'
                 should_render = True
 
             if should_render:
                 display_inline_comments[co.f_path][co.line_no].append(co)
 
         # load diff data into template context, if we use compare mode then
         # diff is calculated based on changes between versions of PR
 
         source_repo = pull_request_at_ver.source_repo
         source_ref_id = pull_request_at_ver.source_ref_parts.commit_id
 
         target_repo = pull_request_at_ver.target_repo
         target_ref_id = pull_request_at_ver.target_ref_parts.commit_id
 
         if compare:
             # in compare switch the diff base to latest commit from prev version
             target_ref_id = prev_pull_request_display_obj.revisions[0]
 
         # despite opening commits for bookmarks/branches/tags, we always
         # convert this to rev to prevent changes after bookmark or branch change
         c.source_ref_type = 'rev'
         c.source_ref = source_ref_id
 
         c.target_ref_type = 'rev'
         c.target_ref = target_ref_id
 
         c.source_repo = source_repo
         c.target_repo = target_repo
 
         # diff_limit is the old behavior, will cut off the whole diff
         # if the limit is applied  otherwise will just hide the
         # big files from the front-end
         diff_limit = self.cut_off_limit_diff
         file_limit = self.cut_off_limit_file
 
         c.commit_ranges = []
         source_commit = EmptyCommit()
         target_commit = EmptyCommit()
         c.missing_requirements = False
 
         source_scm = source_repo.scm_instance()
         target_scm = target_repo.scm_instance()
 
         # try first shadow repo, fallback to regular repo
         try:
             commits_source_repo = pull_request_latest.get_shadow_repo()
         except Exception:
             log.debug('Failed to get shadow repo', exc_info=True)
             commits_source_repo = source_scm
 
         c.commits_source_repo = commits_source_repo
         commit_cache = {}
         try:
             pre_load = ["author", "branch", "date", "message"]
             show_revs = pull_request_at_ver.revisions
             for rev in show_revs:
                 comm = commits_source_repo.get_commit(
                     commit_id=rev, pre_load=pre_load)
                 c.commit_ranges.append(comm)
                 commit_cache[comm.raw_id] = comm
 
             target_commit = commits_source_repo.get_commit(
                 commit_id=safe_str(target_ref_id))
             source_commit = commits_source_repo.get_commit(
                 commit_id=safe_str(source_ref_id))
         except CommitDoesNotExistError:
             pass
         except RepositoryRequirementError:
             log.warning(
                 'Failed to get all required data from repo', exc_info=True)
             c.missing_requirements = True
 
         c.ancestor = None  # set it to None, to hide it from PR view
 
         try:
             ancestor_id = source_scm.get_common_ancestor(
                 source_commit.raw_id, target_commit.raw_id, target_scm)
             c.ancestor_commit = source_scm.get_commit(ancestor_id)
         except Exception:
             c.ancestor_commit = None
 
         c.statuses = source_repo.statuses(
             [x.raw_id for x in c.commit_ranges])
 
         # auto collapse if we have more than limit
         collapse_limit = diffs.DiffProcessor._collapse_commits_over
         c.collapse_all_commits = len(c.commit_ranges) > collapse_limit
         c.compare_mode = compare
 
         c.missing_commits = False
         if (c.missing_requirements or isinstance(source_commit, EmptyCommit)
             or source_commit == target_commit):
 
             c.missing_commits = True
         else:
 
             c.diffset = self._get_diffset(
                 commits_source_repo, source_ref_id, target_ref_id,
                 target_commit, source_commit,
                 diff_limit, file_limit, display_inline_comments)
 
             c.limited_diff = c.diffset.limited_diff
 
             # calculate removed files that are bound to comments
             comment_deleted_files = [
                 fname for fname in display_inline_comments
                 if fname not in c.diffset.file_stats]
 
             c.deleted_files_comments = collections.defaultdict(dict)
             for fname, per_line_comments in display_inline_comments.items():
                 if fname in comment_deleted_files:
                     c.deleted_files_comments[fname]['stats'] = 0
                     c.deleted_files_comments[fname]['comments'] = list()
                     for lno, comments in per_line_comments.items():
                         c.deleted_files_comments[fname]['comments'].extend(
                             comments)
 
         # this is a hack to properly display links, when creating PR, the
         # compare view and others uses different notation, and
         # compare_commits.mako renders links based on the target_repo.
         # We need to swap that here to generate it properly on the html side
         c.target_repo = c.source_repo
 
         c.commit_statuses = ChangesetStatus.STATUSES
 
         c.show_version_changes = not pr_closed
         if c.show_version_changes:
             cur_obj = pull_request_at_ver
             prev_obj = prev_pull_request_at_ver
 
             old_commit_ids = prev_obj.revisions
             new_commit_ids = cur_obj.revisions
             commit_changes = PullRequestModel()._calculate_commit_id_changes(
                 old_commit_ids, new_commit_ids)
             c.commit_changes_summary = commit_changes
 
             # calculate the diff for commits between versions
             c.commit_changes = []
             mark = lambda cs, fw: list(
                 h.itertools.izip_longest([], cs, fillvalue=fw))
             for c_type, raw_id in mark(commit_changes.added, 'a') \
                                 + mark(commit_changes.removed, 'r') \
                                 + mark(commit_changes.common, 'c'):
 
                 if raw_id in commit_cache:
                     commit = commit_cache[raw_id]
                 else:
                     try:
                         commit = commits_source_repo.get_commit(raw_id)
                     except CommitDoesNotExistError:
                         # in case we fail extracting still use "dummy" commit
                         # for display in commit diff
                         commit = h.AttributeDict(
                             {'raw_id': raw_id,
                              'message': 'EMPTY or MISSING COMMIT'})
                 c.commit_changes.append([c_type, commit])
 
             # current user review statuses for each version
             c.review_versions = {}
             if c.rhodecode_user.user_id in allowed_reviewers:
                 for co in general_comments:
                     if co.author.user_id == c.rhodecode_user.user_id:
                         # each comment has a status change
                         status = co.status_change
                         if status:
                             _ver_pr = status[0].comment.pull_request_version_id
                             c.review_versions[_ver_pr] = status[0]
 
         return render('/pullrequests/pullrequest_show.mako')
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     @auth.CSRFRequired()
     @jsonify
     def comment(self, repo_name, pull_request_id):
         pull_request_id = safe_int(pull_request_id)
         pull_request = PullRequest.get_or_404(pull_request_id)
         if pull_request.is_closed():
             raise HTTPForbidden()
 
         status = request.POST.get('changeset_status', None)
         text = request.POST.get('text')
         comment_type = request.POST.get('comment_type')
         resolves_comment_id = request.POST.get('resolves_comment_id', None)
         close_pull_request = request.POST.get('close_pull_request')
 
         close_pr = False
         if close_pull_request:
             close_pr = True
             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
 
         allowed_to_change_status = PullRequestModel().check_user_change_status(
             pull_request, c.rhodecode_user)
 
         if status and allowed_to_change_status:
             message = (_('Status change %(transition_icon)s %(status)s')
                        % {'transition_icon': '>',
                           'status': ChangesetStatus.get_status_lbl(status)})
             if close_pr:
                 message = _('Closing with') + ' ' + message
             text = text or message
         comm = CommentsModel().create(
             text=text,
             repo=c.rhodecode_db_repo.repo_id,
             user=c.rhodecode_user.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),
             status_change_type=(status
                                 if status and allowed_to_change_status else None),
             closing_pr=close_pr,
             comment_type=comment_type,
             resolves_comment_id=resolves_comment_id
         )
 
         if allowed_to_change_status:
             old_calculated_status = pull_request.calculated_review_status()
             # get status if set !
             if status:
                 ChangesetStatusModel().set_status(
                     c.rhodecode_db_repo.repo_id,
                     status,
                     c.rhodecode_user.user_id,
                     comm,
                     pull_request=pull_request_id
                 )
 
             Session().flush()
             events.trigger(events.PullRequestCommentEvent(pull_request, comm))
             # we now calculate the status of pull request, and based on that
             # calculation we set the commits status
             calculated_status = pull_request.calculated_review_status()
             if old_calculated_status != calculated_status:
                 PullRequestModel()._trigger_pull_request_hook(
                     pull_request, c.rhodecode_user, 'review_status_change')
 
             calculated_status_lbl = ChangesetStatus.get_status_lbl(
                 calculated_status)
 
             if close_pr:
                 status_completed = (
                     calculated_status in [ChangesetStatus.STATUS_APPROVED,
                                           ChangesetStatus.STATUS_REJECTED])
                 if close_pull_request or status_completed:
                     PullRequestModel().close_pull_request(
                         pull_request_id, c.rhodecode_user)
                 else:
                     h.flash(_('Closing pull request on other statuses than '
                               'rejected or approved is forbidden. '
                               'Calculated status from all reviewers '
                               'is currently: %s') % calculated_status_lbl,
                             category='warning')
 
         Session().commit()
 
         if not request.is_xhr:
             return redirect(h.url('pullrequest_show', repo_name=repo_name,
                                   pull_request_id=pull_request_id))
 
         data = {
             'target_id': h.safeid(h.safe_unicode(request.POST.get('f_path'))),
         }
         if comm:
             c.co = comm
             c.inline_comment = True if comm.line_no else False
             data.update(comm.get_dict())
             data.update({'rendered_text':
                              render('changeset/changeset_comment_block.mako')})
 
         return data
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                    'repository.admin')
     @auth.CSRFRequired()
     @jsonify
     def delete_comment(self, repo_name, comment_id):
         return self._delete_comment(comment_id)
 
     def _delete_comment(self, comment_id):
         comment_id = safe_int(comment_id)
         co = ChangesetComment.get_or_404(comment_id)
         if co.pull_request.is_closed():
             # don't allow deleting comments on closed pull request
             raise HTTPForbidden()
 
         is_owner = co.author.user_id == c.rhodecode_user.user_id
         is_repo_admin = h.HasRepoPermissionAny('repository.admin')(c.repo_name)
         if h.HasPermissionAny('hg.admin')() or is_repo_admin or is_owner:
             old_calculated_status = co.pull_request.calculated_review_status()
             CommentsModel().delete(comment=co)
             Session().commit()
             calculated_status = co.pull_request.calculated_review_status()
             if old_calculated_status != calculated_status:
                 PullRequestModel()._trigger_pull_request_hook(
                     co.pull_request, c.rhodecode_user, 'review_status_change')
             return True
         else:
             raise HTTPForbidden()

rhodecode/model/pull_request.py

@@ -1,1454 +1,1469 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2012-2017 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
 """
 
 from collections import namedtuple
 import json
 import logging
 import datetime
 import urllib
 
 from pylons.i18n.translation import _
 from pylons.i18n.translation import lazy_ugettext
 from sqlalchemy import or_
 
 from rhodecode.lib import helpers as h, hooks_utils, diffs
 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.utils import action_logger
 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 (
     PullRequest, PullRequestReviewers, ChangesetStatus,
     PullRequestVersion, ChangesetComment, Repository)
 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 = namedtuple(
-    'UpdateResponse', 'executed, reason, new, old, changes')
+UpdateResponse = namedtuple('UpdateResponse', [
+    'executed', 'reason', 'new', 'old', 'changes',
+    'source_changed', 'target_changed'])
 
 
 class PullRequestModel(BaseModel):
 
     cls = PullRequest
 
     DIFF_CONTEXT = 3
 
     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 reference is already '
-            'up to date.'),
+            'No update needed because the source and target have not changed.'),
         UpdateFailureReason.WRONG_REF_TPYE: lazy_ugettext(
             'Pull request cannot be updated because the reference type is '
             'not supported for an update.'),
         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.'),
     }
 
     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 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 create(self, created_by, source_repo, source_ref, target_repo,
         target_ref, revisions, reviewers, title, description=None):
         created_by_user = self._get_user(created_by)
         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.author = created_by_user
 
         Session().add(pull_request)
         Session().flush()
 
         reviewer_ids = set()
         # members / reviewers
         for reviewer_object in reviewers:
             if isinstance(reviewer_object, tuple):
                 user_id, reasons = reviewer_object
             else:
                 user_id, reasons = reviewer_object, []
 
             user = self._get_user(user_id)
             reviewer_ids.add(user.user_id)
 
             reviewer = PullRequestReviewers(user, pull_request, reasons)
             Session().add(reviewer)
 
         # 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
         )
 
         self.notify_reviewers(pull_request, reviewer_ids)
         self._trigger_pull_request_hook(
             pull_request, created_by_user, 'create')
 
         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(self, pull_request, user, extras):
         log.debug("Merging pull request %s", pull_request.pull_request_id)
         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_action('user_merged_pull_request', 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):
         target_vcs = pull_request.target_repo.scm_instance()
         source_vcs = pull_request.source_repo.scm_instance()
         target_ref = self._refresh_reference(
             pull_request.target_ref_parts, target_vcs)
 
         message = _(
             'Merge pull request #%(pr_id)s from '
             '%(source_repo)s %(source_ref_name)s\n\n %(pr_title)s') % {
                 'pr_id': pull_request.pull_request_id,
                 'source_repo': source_vcs.name,
                 'source_ref_name': pull_request.source_ref_parts.name,
                 'pr_title': pull_request.title
             }
 
         workspace_id = self._workspace_id(pull_request)
         use_rebase = self._use_rebase_for_merging(pull_request)
 
         callback_daemon, extras = prepare_callback_daemon(
             extras, protocol=vcs_settings.HOOKS_PROTOCOL,
             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))
             merge_state = target_vcs.merge(
                 target_ref, source_vcs, pull_request.source_ref_parts,
                 workspace_id, user_name=user.username,
                 user_email=user.email, message=message, use_rebase=use_rebase)
         return merge_state
 
     def _comment_and_close_pr(self, pull_request, user, merge_state):
         pull_request.merge_rev = merge_state.merge_ref.commit_id
         pull_request.updated_on = datetime.datetime.now()
 
         CommentsModel().create(
             text=unicode(_('Pull request merged and closed')),
             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 ['book', 'branch', 'tag']
 
     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_TPYE,
-                old=pull_request, new=None, changes=None)
+                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)
+                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)
+                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)
+                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 ('tag', 'branch', 'book'):
                 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)
+                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
 
-        changes = self._calculate_commit_id_changes(
-            old_commit_ids, new_commit_ids)
-
         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)
 
-        file_changes = self._calculate_file_changes(
-            old_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
-        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,
+        # 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,
-                revision=commit_id)
+                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.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')
+        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)
+            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.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())
 
         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, 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, 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)
 
         # 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):
         pull_request = self.__get_pull_request(pull_request)
         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()
         Session().add(pull_request)
 
     def update_reviewers(self, pull_request, reviewer_data):
         """
         Update the reviewers in the pull request
 
         :param pull_request: the pr to update
         :param reviewer_data: list of tuples [(user, ['reason1', 'reason2'])]
         """
 
         reviewers_reasons = {}
         for user_id, reasons in reviewer_data:
             if isinstance(user_id, (int, basestring)):
                 user_id = self._get_user(user_id).user_id
             reviewers_reasons[user_id] = reasons
 
         reviewers_ids = set(reviewers_reasons.keys())
         pull_request = self.__get_pull_request(pull_request)
         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)
             reasons = reviewers_reasons[uid]
             reviewer = PullRequestReviewers(_usr, pull_request, reasons)
             Session().add(reviewer)
 
         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:
                 Session().delete(obj)
 
         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):
         return h.url('pullrequest_show',
                      repo_name=safe_str(pull_request.target_repo.repo_name),
                      pull_request_id=pull_request.pull_request_id,
                      qualified=True)
 
     def get_shadow_clone_url(self, pull_request):
         """
         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))
             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.url(
             'pullrequest_show',
             repo_name=pr_target_repo.repo_name,
             pull_request_id=pull_request_obj.pull_request_id,
             qualified=True,)
 
         # set some variables for email notification
         pr_target_repo_url = h.url(
             'summary_home',
             repo_name=pr_target_repo.repo_name,
             qualified=True)
 
         pr_source_repo_url = h.url(
             'summary_home',
             repo_name=pr_source_repo.repo_name,
             qualified=True)
 
         # 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):
         pull_request = self.__get_pull_request(pull_request)
         self._cleanup_merge_workspace(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')
         self._log_action('user_closed_pull_request', user, pull_request)
 
     def close_pull_request_with_comment(self, pull_request, user, repo,
                                         message=None):
         status = ChangesetStatus.STATUS_REJECTED
 
         if not message:
             message = (
                 _('Status change %(transition_icon)s %(status)s') % {
                     'transition_icon': '>',
                     'status': ChangesetStatus.get_status_lbl(status)})
 
         internal_message = _('Closing with') + ' ' + message
 
         comm = CommentsModel().create(
             text=internal_message,
             repo=repo.repo_id,
             user=user.user_id,
             pull_request=pull_request.pull_request_id,
             f_path=None,
             line_no=None,
             status_change=ChangesetStatus.get_status_lbl(status),
             status_change_type=status,
             closing_pr=True
         )
 
         ChangesetStatusModel().set_status(
             repo.repo_id,
             status,
             user.user_id,
             comm,
             pull_request=pull_request.pull_request_id
         )
         Session().flush()
 
         PullRequestModel().close_pull_request(
             pull_request.pull_request_id, user)
 
     def merge_status(self, pull_request):
         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)
         if not merge_possible:
             return merge_possible, msg
 
         try:
             resp = self._try_merge(pull_request)
             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):
         """
         Check if `target` and `source` have compatible requirements.
 
         Currently this is just checking for largefiles.
         """
         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):
         """
         Try to merge the pull request and return the merge status.
         """
         log.debug(
             "Trying out if the pull request %s can be merged.",
             pull_request.pull_request_id)
         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 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 ('branch', 'book'):
             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()
         use_rebase = self._use_rebase_for_merging(pull_request)
         merge_state = target_vcs.merge(
             target_reference, source_vcs, pull_request.source_ref_parts,
             workspace_id, dry_run=True, use_rebase=use_rebase)
 
         # 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):
         all_refs, selected_ref = \
             self._get_repo_pullrequest_sources(
                 repo.scm_instance(), commit_id=commit_id,
                 branch=branch, bookmark=bookmark)
 
         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.firstname,
                 'lastname': repo.user.lastname,
                 'gravatar_link': h.gravatar_url(repo.user.email, 14),
             },
             'description': h.chop_at_smart(repo.description, '\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
         target_scm = pull_request.target_repo.scm_instance()
         workspace_id = 'pr-%s' % pull_request.pull_request_id
 
         try:
             target_scm.cleanup_merge_workspace(workspace_id)
         except NotImplementedError:
             pass
 
     def _get_repo_pullrequest_sources(
             self, repo, commit_id=None, branch=None, bookmark=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
         """
 
         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:
                 rev = repo.commit_ids[0]
                 selected = 'rev:%s:%s' % (rev, rev)
             else:
                 raise EmptyRepositoryError()
         return groups, selected
 
     def get_diff(self, source_repo, source_ref_id, target_ref_id, context=DIFF_CONTEXT):
         return self._get_diff_from_pr_or_version(
             source_repo, source_ref_id, target_ref_id, context=context)
 
     def _get_diff_from_pr_or_version(
             self, source_repo, source_ref_id, target_ref_id, 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, context=context)
         return vcs_diff
 
     def _is_merge_enabled(self, pull_request):
         settings_model = VcsSettingsModel(repo=pull_request.target_repo)
         settings = settings_model.get_general_settings()
         return settings.get('rhodecode_pr_merge_enabled', False)
 
     def _use_rebase_for_merging(self, pull_request):
         settings_model = VcsSettingsModel(repo=pull_request.target_repo)
         settings = settings_model.get_general_settings()
         return settings.get('rhodecode_hg_use_rebase_for_merging', False)
 
     def _log_action(self, action, user, pull_request):
         action_logger(
             user,
             '{action}:{pr_id}'.format(
                 action=action, pr_id=pull_request.pull_request_id),
             pull_request.target_repo)
 
 
 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, user, fail_early=False, translator=None):
         # if migrated to pyramid...
         # _ = lambda: translator or _  # use passed in translator if any
 
         merge_check = cls()
 
         # permissions to merge
         user_allowed_to_merge = PullRequestModel().check_user_merge(
             pull_request, user)
         if not user_allowed_to_merge:
             log.debug("MergeCheck: cannot merge, approval is pending.")
 
             msg = _('User `{}` not allowed to perform merge.').format(user.username)
             merge_check.push_error('error', msg, cls.PERM_CHECK, 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
         merge_status, msg = PullRequestModel().merge_status(pull_request)
         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
 
         return merge_check
 
 
 ChangeTuple = namedtuple('ChangeTuple',
                          ['added', 'common', 'removed', 'total'])
 
 FileChangeTuple = namedtuple('FileChangeTuple',
                              ['added', 'modified', 'removed'])