pull-requests: added retry mechanism for updating pull requests.

rhodecode/apps/repository/views/repo_pull_requests.py

@@ -1,1868 +1,1872 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2011-2020 RhodeCode GmbH
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License, version 3
 # (only), as published by the Free Software Foundation.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 # This program is dual-licensed. If you wish to learn more about the
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 import logging
 import collections
 
 import formencode
 import formencode.htmlfill
 import peppercorn
 from pyramid.httpexceptions import (
     HTTPFound, HTTPNotFound, HTTPForbidden, HTTPBadRequest, HTTPConflict)
 
 from pyramid.renderers import render
 
 from rhodecode.apps._base import RepoAppView, DataGridAppView
 
 from rhodecode.lib import helpers as h, diffs, codeblocks, channelstream
 from rhodecode.lib.base import vcs_operation_context
 from rhodecode.lib.diffs import load_cached_diff, cache_diff, diff_cache_exist
 from rhodecode.lib.exceptions import CommentVersionMismatch
 from rhodecode.lib.ext_json import json
 from rhodecode.lib.auth import (
     LoginRequired, HasRepoPermissionAny, HasRepoPermissionAnyDecorator,
     NotAnonymous, CSRFRequired)
-from rhodecode.lib.utils2 import str2bool, safe_str, safe_unicode, safe_int, aslist
+from rhodecode.lib.utils2 import str2bool, safe_str, safe_unicode, safe_int, aslist, retry
 from rhodecode.lib.vcs.backends.base import (
     EmptyCommit, UpdateFailureReason, unicode_to_reference)
 from rhodecode.lib.vcs.exceptions import (
     CommitDoesNotExistError, RepositoryRequirementError, EmptyRepositoryError)
 from rhodecode.model.changeset_status import ChangesetStatusModel
 from rhodecode.model.comment import CommentsModel
 from rhodecode.model.db import (
     func, false, or_, PullRequest, ChangesetComment, ChangesetStatus, Repository,
     PullRequestReviewers)
 from rhodecode.model.forms import PullRequestForm
 from rhodecode.model.meta import Session
 from rhodecode.model.pull_request import PullRequestModel, MergeCheck
 from rhodecode.model.scm import ScmModel
 
 log = logging.getLogger(__name__)
 
 
 class RepoPullRequestsView(RepoAppView, DataGridAppView):
 
     def load_default_context(self):
         c = self._get_local_tmpl_context(include_app_defaults=True)
         c.REVIEW_STATUS_APPROVED = ChangesetStatus.STATUS_APPROVED
         c.REVIEW_STATUS_REJECTED = ChangesetStatus.STATUS_REJECTED
         # backward compat., we use for OLD PRs a plain renderer
         c.renderer = 'plain'
         return c
 
     def _get_pull_requests_list(
             self, repo_name, source, filter_type, opened_by, statuses):
 
         draw, start, limit = self._extract_chunk(self.request)
         search_q, order_by, order_dir = self._extract_ordering(self.request)
         _render = self.request.get_partial_renderer(
             'rhodecode:templates/data_table/_dt_elements.mako')
 
         # pagination
 
         if filter_type == 'awaiting_review':
             pull_requests = PullRequestModel().get_awaiting_review(
                 repo_name,
                 search_q=search_q, statuses=statuses,
                 offset=start, length=limit, order_by=order_by, order_dir=order_dir)
             pull_requests_total_count = PullRequestModel().count_awaiting_review(
                 repo_name,
                 search_q=search_q, statuses=statuses)
         elif filter_type == 'awaiting_my_review':
             pull_requests = PullRequestModel().get_awaiting_my_review(
                 repo_name, self._rhodecode_user.user_id,
                 search_q=search_q, statuses=statuses,
                 offset=start, length=limit, order_by=order_by, order_dir=order_dir)
             pull_requests_total_count = PullRequestModel().count_awaiting_my_review(
                 repo_name, self._rhodecode_user.user_id,
                 search_q=search_q, statuses=statuses)
         else:
             pull_requests = PullRequestModel().get_all(
                 repo_name, search_q=search_q, source=source, opened_by=opened_by,
                 statuses=statuses, offset=start, length=limit,
                 order_by=order_by, order_dir=order_dir)
             pull_requests_total_count = PullRequestModel().count_all(
                 repo_name, search_q=search_q, source=source, statuses=statuses,
                 opened_by=opened_by)
 
         data = []
         comments_model = CommentsModel()
         for pr in pull_requests:
             comments_count = comments_model.get_all_comments(
                 self.db_repo.repo_id, pull_request=pr,
                 include_drafts=False, count_only=True)
 
             review_statuses = pr.reviewers_statuses(user=self._rhodecode_db_user)
             my_review_status = ChangesetStatus.STATUS_NOT_REVIEWED
             if review_statuses and review_statuses[4]:
                 _review_obj, _user, _reasons, _mandatory, statuses = review_statuses
                 my_review_status = statuses[0][1].status
 
             data.append({
                 'name': _render('pullrequest_name',
                                 pr.pull_request_id, pr.pull_request_state,
                                 pr.work_in_progress, pr.target_repo.repo_name,
                                 short=True),
                 'name_raw': pr.pull_request_id,
                 'status': _render('pullrequest_status',
                                   pr.calculated_review_status()),
                 'my_status': _render('pullrequest_status',
                                      my_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),
                                       pr.versions_count),
                 '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),
                 'state': pr.pull_request_state,
                 'author': _render('pullrequest_author',
                                   pr.author.full_contact, ),
                 'author_raw': pr.author.full_name,
                 'comments': _render('pullrequest_comments', comments_count),
                 'comments_raw': comments_count,
                 'closed': pr.is_closed(),
             })
 
         data = ({
             'draw': draw,
             'data': data,
             'recordsTotal': pull_requests_total_count,
             'recordsFiltered': pull_requests_total_count,
         })
         return data
 
     @LoginRequired()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     def pull_request_list(self):
         c = self.load_default_context()
 
         req_get = self.request.GET
         c.source = str2bool(req_get.get('source'))
         c.closed = str2bool(req_get.get('closed'))
         c.my = str2bool(req_get.get('my'))
         c.awaiting_review = str2bool(req_get.get('awaiting_review'))
         c.awaiting_my_review = str2bool(req_get.get('awaiting_my_review'))
 
         c.active = 'open'
         if c.my:
             c.active = 'my'
         if c.closed:
             c.active = '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'
 
         return self._get_template_context(c)
 
     @LoginRequired()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     def pull_request_list_data(self):
         self.load_default_context()
 
         # additional filters
         req_get = self.request.GET
         source = str2bool(req_get.get('source'))
         closed = str2bool(req_get.get('closed'))
         my = str2bool(req_get.get('my'))
         awaiting_review = str2bool(req_get.get('awaiting_review'))
         awaiting_my_review = str2bool(req_get.get('awaiting_my_review'))
 
         filter_type = 'awaiting_review' if awaiting_review \
             else 'awaiting_my_review' if awaiting_my_review \
             else None
 
         opened_by = None
         if my:
             opened_by = [self._rhodecode_user.user_id]
 
         statuses = [PullRequest.STATUS_NEW, PullRequest.STATUS_OPEN]
         if closed:
             statuses = [PullRequest.STATUS_CLOSED]
 
         data = self._get_pull_requests_list(
             repo_name=self.db_repo_name, source=source,
             filter_type=filter_type, opened_by=opened_by, statuses=statuses)
 
         return data
 
     def _is_diff_cache_enabled(self, target_repo):
         caching_enabled = self._get_general_setting(
             target_repo, 'rhodecode_diff_cache')
         log.debug('Diff caching enabled: %s', caching_enabled)
         return caching_enabled
 
     def _get_diffset(self, source_repo_name, source_repo,
                      ancestor_commit,
                      source_ref_id, target_ref_id,
                      target_commit, source_commit, diff_limit, file_limit,
                      fulldiff, hide_whitespace_changes, diff_context, use_ancestor=True):
 
         target_commit_final = target_commit
         source_commit_final = source_commit
 
         if use_ancestor:
             # we might want to not use it for versions
             target_ref_id = ancestor_commit.raw_id
             target_commit_final = ancestor_commit
 
         vcs_diff = PullRequestModel().get_diff(
             source_repo, source_ref_id, target_ref_id,
             hide_whitespace_changes, diff_context)
 
         diff_processor = diffs.DiffProcessor(
             vcs_diff, format='newdiff', diff_limit=diff_limit,
             file_limit=file_limit, show_full_diff=fulldiff)
 
         _parsed = diff_processor.prepare()
 
         diffset = codeblocks.DiffSet(
             repo_name=self.db_repo_name,
             source_repo_name=source_repo_name,
             source_node_getter=codeblocks.diffset_node_getter(target_commit_final),
             target_node_getter=codeblocks.diffset_node_getter(source_commit_final),
         )
         diffset = self.path_filter.render_patchset_filtered(
             diffset, _parsed, target_ref_id, source_ref_id)
 
         return diffset
 
     def _get_range_diffset(self, source_scm, source_repo,
                            commit1, commit2, diff_limit, file_limit,
                            fulldiff, hide_whitespace_changes, diff_context):
         vcs_diff = source_scm.get_diff(
             commit1, commit2,
             ignore_whitespace=hide_whitespace_changes,
             context=diff_context)
 
         diff_processor = diffs.DiffProcessor(
             vcs_diff, format='newdiff', diff_limit=diff_limit,
             file_limit=file_limit, show_full_diff=fulldiff)
 
         _parsed = diff_processor.prepare()
 
         diffset = codeblocks.DiffSet(
             repo_name=source_repo.repo_name,
             source_node_getter=codeblocks.diffset_node_getter(commit1),
             target_node_getter=codeblocks.diffset_node_getter(commit2))
 
         diffset = self.path_filter.render_patchset_filtered(
             diffset, _parsed, commit1.raw_id, commit2.raw_id)
 
         return diffset
 
     def register_comments_vars(self, c, pull_request, versions, include_drafts=True):
         comments_model = CommentsModel()
 
         # GENERAL COMMENTS with versions #
         q = comments_model._all_general_comments_of_pull_request(pull_request)
         q = q.order_by(ChangesetComment.comment_id.asc())
         if not include_drafts:
             q = q.filter(ChangesetComment.draft == false())
         general_comments = q
 
         # pick comments we want to render at current version
         c.comment_versions = comments_model.aggregate_comments(
             general_comments, versions, c.at_version_num)
 
         # INLINE COMMENTS with versions  #
         q = comments_model._all_inline_comments_of_pull_request(pull_request)
         q = q.order_by(ChangesetComment.comment_id.asc())
         if not include_drafts:
             q = q.filter(ChangesetComment.draft == false())
         inline_comments = q
 
         c.inline_versions = comments_model.aggregate_comments(
             inline_comments, versions, c.at_version_num, inline=True)
 
         # Comments inline+general
         if c.at_version:
             c.inline_comments_flat = c.inline_versions[c.at_version_num]['display']
             c.comments = c.comment_versions[c.at_version_num]['display']
         else:
             c.inline_comments_flat = c.inline_versions[c.at_version_num]['until']
             c.comments = c.comment_versions[c.at_version_num]['until']
 
         return general_comments, inline_comments
 
     @LoginRequired()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     def pull_request_show(self):
         _ = self.request.translate
         c = self.load_default_context()
 
         pull_request = PullRequest.get_or_404(
             self.request.matchdict['pull_request_id'])
         pull_request_id = pull_request.pull_request_id
 
         c.state_progressing = pull_request.is_state_changing()
         c.pr_broadcast_channel = channelstream.pr_channel(pull_request)
 
         _new_state = {
             'created': PullRequest.STATE_CREATED,
         }.get(self.request.GET.get('force_state'))
 
         if c.is_super_admin and _new_state:
             with pull_request.set_state(PullRequest.STATE_UPDATING, final_state=_new_state):
                 h.flash(
                     _('Pull Request state was force changed to `{}`').format(_new_state),
                     category='success')
                 Session().commit()
 
             raise HTTPFound(h.route_path(
                 'pullrequest_show', repo_name=self.db_repo_name,
                 pull_request_id=pull_request_id))
 
         version = self.request.GET.get('version')
         from_version = self.request.GET.get('from_version') or version
         merge_checks = self.request.GET.get('merge_checks')
         c.fulldiff = str2bool(self.request.GET.get('fulldiff'))
         force_refresh = str2bool(self.request.GET.get('force_refresh'))
         c.range_diff_on = self.request.GET.get('range-diff') == "1"
 
         # fetch global flags of ignore ws or context lines
         diff_context = diffs.get_diff_context(self.request)
         hide_whitespace_changes = diffs.get_diff_whitespace_flag(self.request)
 
         (pull_request_latest,
          pull_request_at_ver,
          pull_request_display_obj,
          at_version) = PullRequestModel().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 for closed PR
             raise HTTPFound(h.route_path(
                 'pullrequest_show', repo_name=self.db_repo_name,
                 pull_request_id=pull_request_id))
 
         versions = pull_request_display_obj.versions()
 
         c.commit_versions = PullRequestModel().pr_commits_versions(versions)
 
         # used to store per-commit range diffs
         c.changes = collections.OrderedDict()
 
         c.at_version = at_version
         c.at_version_num = (at_version
                             if at_version and at_version != PullRequest.LATEST_VER
                             else None)
 
         c.at_version_index = 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) = PullRequestModel().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 != PullRequest.LATEST_VER
                               else None)
         c.from_version_index = 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 self.db_repo_name != pull_request_at_ver.target_repo.repo_name:
             log.warning('Mismatch between the current repo: %s, and target %s',
                         self.db_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.renderer = pull_request_at_ver.description_renderer or c.renderer
         c.pull_request_latest = pull_request_latest
 
         # inject latest version
         latest_ver = PullRequest.get_pr_display_object(pull_request_latest, pull_request_latest)
         c.versions = versions + [latest_ver]
 
         if compare or (at_version and not at_version == PullRequest.LATEST_VER):
             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:
             can_change_status = PullRequestModel().check_user_change_status(
                 pull_request_at_ver, self._rhodecode_user)
             c.allowed_to_change_status = can_change_status and not pr_closed
 
             c.allowed_to_update = PullRequestModel().check_user_update(
                 pull_request_latest, self._rhodecode_user) and not pr_closed
             c.allowed_to_merge = PullRequestModel().check_user_merge(
                 pull_request_latest, self._rhodecode_user) and not pr_closed
             c.allowed_to_delete = PullRequestModel().check_user_delete(
                 pull_request_latest, self._rhodecode_user) and not pr_closed
             c.allowed_to_comment = not pr_closed
             c.allowed_to_close = c.allowed_to_merge and not pr_closed
 
         c.forbid_adding_reviewers = False
 
         if pull_request_latest.reviewer_data and \
                         'rules' in pull_request_latest.reviewer_data:
             rules = pull_request_latest.reviewer_data['rules'] or {}
             try:
                 c.forbid_adding_reviewers = rules.get('forbid_adding_reviewers')
             except Exception:
                 pass
 
         # check merge capabilities
         _merge_check = MergeCheck.validate(
             pull_request_latest, auth_user=self._rhodecode_user,
             translator=self.request.translate,
             force_shadow_repo_refresh=force_refresh)
 
         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.pr_merge_source_commit = _merge_check.source_commit
         c.pr_merge_target_commit = _merge_check.target_commit
 
         c.pr_merge_info = MergeCheck.get_merge_conditions(
             pull_request_latest, translator=self.request.translate)
 
         c.pull_request_review_status = _merge_check.review_status
         if merge_checks:
             self.request.override_renderer = \
                 'rhodecode:templates/pullrequests/pullrequest_merge_checks.mako'
             return self._get_template_context(c)
 
         c.reviewers_count = pull_request.reviewers_count
         c.observers_count = pull_request.observers_count
 
         # reviewers and statuses
         c.pull_request_default_reviewers_data_json = json.dumps(pull_request.reviewer_data)
         c.pull_request_set_reviewers_data_json = collections.OrderedDict({'reviewers': []})
         c.pull_request_set_observers_data_json = collections.OrderedDict({'observers': []})
 
         for review_obj, member, reasons, mandatory, status in pull_request_at_ver.reviewers_statuses():
             member_reviewer = h.reviewer_as_json(
                 member, reasons=reasons, mandatory=mandatory,
                 role=review_obj.role,
                 user_group=review_obj.rule_user_group_data()
             )
 
             current_review_status = status[0][1].status if status else ChangesetStatus.STATUS_NOT_REVIEWED
             member_reviewer['review_status'] = current_review_status
             member_reviewer['review_status_label'] = h.commit_status_lbl(current_review_status)
             member_reviewer['allowed_to_update'] = c.allowed_to_update
             c.pull_request_set_reviewers_data_json['reviewers'].append(member_reviewer)
 
         c.pull_request_set_reviewers_data_json = json.dumps(c.pull_request_set_reviewers_data_json)
 
         for observer_obj, member in pull_request_at_ver.observers():
             member_observer = h.reviewer_as_json(
                 member, reasons=[], mandatory=False,
                 role=observer_obj.role,
                 user_group=observer_obj.rule_user_group_data()
             )
             member_observer['allowed_to_update'] = c.allowed_to_update
             c.pull_request_set_observers_data_json['observers'].append(member_observer)
 
         c.pull_request_set_observers_data_json = json.dumps(c.pull_request_set_observers_data_json)
 
         general_comments, inline_comments = \
             self.register_comments_vars(c, pull_request_latest, versions)
 
         # TODOs
         c.unresolved_comments = CommentsModel() \
             .get_pull_request_unresolved_todos(pull_request_latest)
         c.resolved_comments = CommentsModel() \
             .get_pull_request_resolved_todos(pull_request_latest)
 
         # Drafts
         c.draft_comments = CommentsModel().get_pull_request_drafts(
             self._rhodecode_db_user.user_id,
             pull_request_latest)
 
         # 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
 
         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()
 
         shadow_scm = None
         try:
             shadow_scm = pull_request_latest.get_shadow_repo()
         except Exception:
             log.debug('Failed to get shadow repo', exc_info=True)
         # try first the existing source_repo, and then shadow
         # repo if we can obtain one
         commits_source_repo = source_scm
         if shadow_scm:
             commits_source_repo = shadow_scm
 
         c.commits_source_repo = commits_source_repo
         c.ancestor = None  # set it to None, to hide it from PR view
 
         # empty version means latest, so we keep this to prevent
         # double caching
         version_normalized = version or PullRequest.LATEST_VER
         from_version_normalized = from_version or PullRequest.LATEST_VER
 
         cache_path = self.rhodecode_vcs_repo.get_create_shadow_cache_pr_path(target_repo)
         cache_file_path = diff_cache_exist(
             cache_path, 'pull_request', pull_request_id, version_normalized,
             from_version_normalized, source_ref_id, target_ref_id,
             hide_whitespace_changes, diff_context, c.fulldiff)
 
         caching_enabled = self._is_diff_cache_enabled(c.target_repo)
         force_recache = self.get_recache_flag()
 
         cached_diff = None
         if caching_enabled:
             cached_diff = load_cached_diff(cache_file_path)
 
         has_proper_commit_cache = (
                 cached_diff and cached_diff.get('commits')
                 and len(cached_diff.get('commits', [])) == 5
                 and cached_diff.get('commits')[0]
                 and cached_diff.get('commits')[3])
 
         if not force_recache and not c.range_diff_on and has_proper_commit_cache:
             diff_commit_cache = \
                 (ancestor_commit, commit_cache, missing_requirements,
                  source_commit, target_commit) = cached_diff['commits']
         else:
             # NOTE(marcink): we reach potentially unreachable errors when a PR has
             # merge errors resulting in potentially hidden commits in the shadow repo.
             maybe_unreachable = _merge_check.MERGE_CHECK in _merge_check.error_details \
                                 and _merge_check.merge_response
             maybe_unreachable = maybe_unreachable \
                                 and _merge_check.merge_response.metadata.get('unresolved_files')
             log.debug("Using unreachable commits due to MERGE_CHECK in merge simulation")
             diff_commit_cache = \
                 (ancestor_commit, commit_cache, missing_requirements,
                  source_commit, target_commit) = self.get_commits(
                     commits_source_repo,
                     pull_request_at_ver,
                     source_commit,
                     source_ref_id,
                     source_scm,
                     target_commit,
                     target_ref_id,
                     target_scm,
                 maybe_unreachable=maybe_unreachable)
 
         # register our commit range
         for comm in commit_cache.values():
             c.commit_ranges.append(comm)
 
         c.missing_requirements = missing_requirements
         c.ancestor_commit = ancestor_commit
         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
 
         # 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 = c.visual.cut_off_limit_diff
         file_limit = c.visual.cut_off_limit_file
 
         c.missing_commits = False
         if (c.missing_requirements
             or isinstance(source_commit, EmptyCommit)
             or source_commit == target_commit):
 
             c.missing_commits = True
         else:
             c.inline_comments = display_inline_comments
 
             use_ancestor = True
             if from_version_normalized != version_normalized:
                 use_ancestor = False
 
             has_proper_diff_cache = cached_diff and cached_diff.get('commits')
             if not force_recache and has_proper_diff_cache:
                 c.diffset = cached_diff['diff']
             else:
                 try:
                     c.diffset = self._get_diffset(
                         c.source_repo.repo_name, commits_source_repo,
                         c.ancestor_commit,
                         source_ref_id, target_ref_id,
                         target_commit, source_commit,
                         diff_limit, file_limit, c.fulldiff,
                         hide_whitespace_changes, diff_context,
                         use_ancestor=use_ancestor
                     )
 
                     # save cached diff
                     if caching_enabled:
                         cache_diff(cache_file_path, c.diffset, diff_commit_cache)
                 except CommitDoesNotExistError:
                     log.exception('Failed to generate diffset')
                     c.missing_commits = True
 
             if not c.missing_commits:
 
                 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)
 
                 # maybe calculate the range diff
                 if c.range_diff_on:
                     # TODO(marcink): set whitespace/context
                     context_lcl = 3
                     ign_whitespace_lcl = False
 
                     for commit in c.commit_ranges:
                         commit2 = commit
                         commit1 = commit.first_parent
 
                         range_diff_cache_file_path = diff_cache_exist(
                             cache_path, 'diff', commit.raw_id,
                             ign_whitespace_lcl, context_lcl, c.fulldiff)
 
                         cached_diff = None
                         if caching_enabled:
                             cached_diff = load_cached_diff(range_diff_cache_file_path)
 
                         has_proper_diff_cache = cached_diff and cached_diff.get('diff')
                         if not force_recache and has_proper_diff_cache:
                             diffset = cached_diff['diff']
                         else:
                             diffset = self._get_range_diffset(
                                 commits_source_repo, source_repo,
                                 commit1, commit2, diff_limit, file_limit,
                                 c.fulldiff, ign_whitespace_lcl, context_lcl
                             )
 
                         # save cached diff
                         if caching_enabled:
                             cache_diff(range_diff_cache_file_path, diffset, None)
 
                         c.changes[commit.raw_id] = diffset
 
         # 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 = []
 
             def mark(cs, fw):
                 return 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 = {}
             is_reviewer = PullRequestModel().is_user_reviewer(
                 pull_request, self._rhodecode_user)
             if is_reviewer:
                 for co in general_comments:
                     if co.author.user_id == self._rhodecode_user.user_id:
                         status = co.status_change
                         if status:
                             _ver_pr = status[0].comment.pull_request_version_id
                             c.review_versions[_ver_pr] = status[0]
 
         return self._get_template_context(c)
 
     def get_commits(
             self, commits_source_repo, pull_request_at_ver, source_commit,
             source_ref_id, source_scm, target_commit, target_ref_id, target_scm,
             maybe_unreachable=False):
 
         commit_cache = collections.OrderedDict()
         missing_requirements = False
 
         try:
             pre_load = ["author", "date", "message", "branch", "parents"]
 
             pull_request_commits = pull_request_at_ver.revisions
             log.debug('Loading %s commits from %s',
                       len(pull_request_commits), commits_source_repo)
 
             for rev in pull_request_commits:
                 comm = commits_source_repo.get_commit(commit_id=rev, pre_load=pre_load,
                                                       maybe_unreachable=maybe_unreachable)
                 commit_cache[comm.raw_id] = comm
 
             # Order here matters, we first need to get target, and then
             # the source
             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), maybe_unreachable=True)
         except CommitDoesNotExistError:
             log.warning('Failed to get commit from `{}` repo'.format(
                 commits_source_repo), exc_info=True)
         except RepositoryRequirementError:
             log.warning('Failed to get all required data from repo', exc_info=True)
             missing_requirements = True
 
         pr_ancestor_id = pull_request_at_ver.common_ancestor_id
 
         try:
             ancestor_commit = source_scm.get_commit(pr_ancestor_id)
         except Exception:
             ancestor_commit = None
 
         return ancestor_commit, commit_cache, missing_requirements, source_commit, target_commit
 
     def assure_not_empty_repo(self):
         _ = self.request.translate
 
         try:
             self.db_repo.scm_instance().get_commit()
         except EmptyRepositoryError:
             h.flash(h.literal(_('There are no commits yet')),
                     category='warning')
             raise HTTPFound(
                 h.route_path('repo_summary', repo_name=self.db_repo.repo_name))
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     def pull_request_new(self):
         _ = self.request.translate
         c = self.load_default_context()
 
         self.assure_not_empty_repo()
         source_repo = self.db_repo
 
         commit_id = self.request.GET.get('commit')
         branch_ref = self.request.GET.get('branch')
         bookmark_ref = self.request.GET.get('bookmark')
 
         try:
             source_repo_data = PullRequestModel().generate_repo_data(
                 source_repo, commit_id=commit_id,
                 branch=branch_ref, bookmark=bookmark_ref,
                 translator=self.request.translate)
         except CommitDoesNotExistError as e:
             log.exception(e)
             h.flash(_('Commit does not exist'), 'error')
             raise HTTPFound(
                 h.route_path('pullrequest_new', repo_name=source_repo.repo_name))
 
         default_target_repo = source_repo
 
         if source_repo.parent and c.has_origin_repo_read_perm:
             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, translator=self.request.translate)
 
         selected_source_ref = source_repo_data['refs']['selected_ref']
         title_source_ref = ''
         if selected_source_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 self._get_template_context(c)
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     def pull_request_repo_refs(self):
         self.load_default_context()
         target_repo_name = self.request.matchdict['target_repo_name']
         repo = Repository.get_by_repo_name(target_repo_name)
         if not repo:
             raise HTTPNotFound()
 
         target_perm = HasRepoPermissionAny(
             'repository.read', 'repository.write', 'repository.admin')(
             target_repo_name)
         if not target_perm:
             raise HTTPNotFound()
 
         return PullRequestModel().generate_repo_data(
             repo, translator=self.request.translate)
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     def pullrequest_repo_targets(self):
         _ = self.request.translate
         filter_query = self.request.GET.get('query')
 
         # get the parents
         parent_target_repos = []
         if self.db_repo.parent:
             parents_query = Repository.query() \
                 .order_by(func.length(Repository.repo_name)) \
                 .filter(Repository.fork_id == self.db_repo.parent.repo_id)
 
             if filter_query:
                 ilike_expression = u'%{}%'.format(safe_unicode(filter_query))
                 parents_query = parents_query.filter(
                     Repository.repo_name.ilike(ilike_expression))
             parents = parents_query.limit(20).all()
 
             for parent in parents:
                 parent_vcs_obj = parent.scm_instance()
                 if parent_vcs_obj and not parent_vcs_obj.is_empty():
                     parent_target_repos.append(parent)
 
         # get other forks, and repo itself
         query = Repository.query() \
             .order_by(func.length(Repository.repo_name)) \
             .filter(
                 or_(Repository.repo_id == self.db_repo.repo_id,  # repo itself
                     Repository.fork_id == self.db_repo.repo_id)  # forks of this repo
             )  \
             .filter(~Repository.repo_id.in_([x.repo_id for x in parent_target_repos]))
 
         if filter_query:
             ilike_expression = u'%{}%'.format(safe_unicode(filter_query))
             query = query.filter(Repository.repo_name.ilike(ilike_expression))
 
         limit = max(20 - len(parent_target_repos), 5)  # not less then 5
         target_repos = query.limit(limit).all()
 
         all_target_repos = target_repos + parent_target_repos
 
         repos = []
         # This checks permissions to the repositories
         for obj in ScmModel().get_repos(all_target_repos):
             repos.append({
                 'id': obj['name'],
                 'text': obj['name'],
                 'type': 'repo',
                 'repo_id': obj['dbrepo']['repo_id'],
                 'repo_type': obj['dbrepo']['repo_type'],
                 'private': obj['dbrepo']['private'],
 
             })
 
         data = {
             'more': False,
             'results': [{
                 'text': _('Repositories'),
                 'children': repos
             }] if repos else []
         }
         return data
 
     @classmethod
     def get_comment_ids(cls, post_data):
         return filter(lambda e: e > 0, map(safe_int, aslist(post_data.get('comments'), ',')))
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     def pullrequest_comments(self):
         self.load_default_context()
 
         pull_request = PullRequest.get_or_404(
             self.request.matchdict['pull_request_id'])
         pull_request_id = pull_request.pull_request_id
         version = self.request.GET.get('version')
 
         _render = self.request.get_partial_renderer(
             'rhodecode:templates/base/sidebar.mako')
         c = _render.get_call_context()
 
         (pull_request_latest,
          pull_request_at_ver,
          pull_request_display_obj,
          at_version) = PullRequestModel().get_pr_version(
             pull_request_id, version=version)
         versions = pull_request_display_obj.versions()
         latest_ver = PullRequest.get_pr_display_object(pull_request_latest, pull_request_latest)
         c.versions = versions + [latest_ver]
 
         c.at_version = at_version
         c.at_version_num = (at_version
                             if at_version and at_version != PullRequest.LATEST_VER
                             else None)
 
         self.register_comments_vars(c, pull_request_latest, versions, include_drafts=False)
         all_comments = c.inline_comments_flat + c.comments
 
         existing_ids = self.get_comment_ids(self.request.POST)
         return _render('comments_table', all_comments, len(all_comments),
                        existing_ids=existing_ids)
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     def pullrequest_todos(self):
         self.load_default_context()
 
         pull_request = PullRequest.get_or_404(
             self.request.matchdict['pull_request_id'])
         pull_request_id = pull_request.pull_request_id
         version = self.request.GET.get('version')
 
         _render = self.request.get_partial_renderer(
             'rhodecode:templates/base/sidebar.mako')
         c = _render.get_call_context()
         (pull_request_latest,
          pull_request_at_ver,
          pull_request_display_obj,
          at_version) = PullRequestModel().get_pr_version(
             pull_request_id, version=version)
         versions = pull_request_display_obj.versions()
         latest_ver = PullRequest.get_pr_display_object(pull_request_latest, pull_request_latest)
         c.versions = versions + [latest_ver]
 
         c.at_version = at_version
         c.at_version_num = (at_version
                             if at_version and at_version != PullRequest.LATEST_VER
                             else None)
 
         c.unresolved_comments = CommentsModel() \
             .get_pull_request_unresolved_todos(pull_request, include_drafts=False)
         c.resolved_comments = CommentsModel() \
             .get_pull_request_resolved_todos(pull_request, include_drafts=False)
 
         all_comments = c.unresolved_comments + c.resolved_comments
         existing_ids = self.get_comment_ids(self.request.POST)
         return _render('comments_table', all_comments, len(c.unresolved_comments),
                        todo_comments=True, existing_ids=existing_ids)
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     def pullrequest_drafts(self):
         self.load_default_context()
 
         pull_request = PullRequest.get_or_404(
             self.request.matchdict['pull_request_id'])
         pull_request_id = pull_request.pull_request_id
         version = self.request.GET.get('version')
 
         _render = self.request.get_partial_renderer(
             'rhodecode:templates/base/sidebar.mako')
         c = _render.get_call_context()
 
         (pull_request_latest,
          pull_request_at_ver,
          pull_request_display_obj,
          at_version) = PullRequestModel().get_pr_version(
             pull_request_id, version=version)
         versions = pull_request_display_obj.versions()
         latest_ver = PullRequest.get_pr_display_object(pull_request_latest, pull_request_latest)
         c.versions = versions + [latest_ver]
 
         c.at_version = at_version
         c.at_version_num = (at_version
                             if at_version and at_version != PullRequest.LATEST_VER
                             else None)
 
         c.draft_comments = CommentsModel() \
             .get_pull_request_drafts(self._rhodecode_db_user.user_id, pull_request)
 
         all_comments = c.draft_comments
 
         existing_ids = self.get_comment_ids(self.request.POST)
         return _render('comments_table', all_comments, len(all_comments),
                        existing_ids=existing_ids, draft_comments=True)
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     @CSRFRequired()
     def pull_request_create(self):
         _ = self.request.translate
         self.assure_not_empty_repo()
         self.load_default_context()
 
         controls = peppercorn.parse(self.request.POST.items())
 
         try:
             form = PullRequestForm(
                 self.request.translate, self.db_repo.repo_id)()
             _form = form.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 = errors.error_dict.get('pullrequest_title')
             else:
                 msg = _('Error creating pull request: {}').format(errors)
             log.exception(msg)
             h.flash(msg, 'error')
 
             # would rather just go back to form ...
             raise HTTPFound(
                 h.route_path('pullrequest_new', repo_name=self.db_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]
         common_ancestor_id = _form['common_ancestor']
 
         # 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'])
 
         if not (source_db_repo or target_db_repo):
             h.flash(_('source_repo or target repo not found'), category='error')
             raise HTTPFound(
                 h.route_path('pullrequest_new', repo_name=self.db_repo_name))
 
         # re-check permissions again here
         # source_repo we must have read permissions
 
         source_perm = HasRepoPermissionAny(
             'repository.read', 'repository.write', 'repository.admin')(
             source_db_repo.repo_name)
         if not source_perm:
             msg = _('Not Enough permissions to source repo `{}`.'.format(
                 source_db_repo.repo_name))
             h.flash(msg, category='error')
             # copy the args back to redirect
             org_query = self.request.GET.mixed()
             raise HTTPFound(
                 h.route_path('pullrequest_new', repo_name=self.db_repo_name,
                              _query=org_query))
 
         # target repo we must have read permissions, and also later on
         # we want to check branch permissions here
         target_perm = HasRepoPermissionAny(
             'repository.read', 'repository.write', 'repository.admin')(
             target_db_repo.repo_name)
         if not target_perm:
             msg = _('Not Enough permissions to target repo `{}`.'.format(
                 target_db_repo.repo_name))
             h.flash(msg, category='error')
             # copy the args back to redirect
             org_query = self.request.GET.mixed()
             raise HTTPFound(
                 h.route_path('pullrequest_new', repo_name=self.db_repo_name,
                              _query=org_query))
 
         source_scm = source_db_repo.scm_instance()
         target_scm = target_db_repo.scm_instance()
 
         source_ref_obj = unicode_to_reference(source_ref)
         target_ref_obj = unicode_to_reference(target_ref)
 
         source_commit = source_scm.get_commit(source_ref_obj.commit_id)
         target_commit = target_scm.get_commit(target_ref_obj.commit_id)
 
         ancestor = source_scm.get_common_ancestor(
             source_commit.raw_id, target_commit.raw_id, target_scm)
 
         # recalculate target ref based on ancestor
         target_ref = ':'.join((target_ref_obj.type, target_ref_obj.name, ancestor))
 
         get_default_reviewers_data, validate_default_reviewers, validate_observers = \
             PullRequestModel().get_reviewer_functions()
 
         # recalculate reviewers logic, to make sure we can validate this
         reviewer_rules = get_default_reviewers_data(
             self._rhodecode_db_user,
             source_db_repo,
             source_ref_obj,
             target_db_repo,
             target_ref_obj,
             include_diff_info=False)
 
         reviewers = validate_default_reviewers(_form['review_members'], reviewer_rules)
         observers = validate_observers(_form['observer_members'], reviewer_rules)
 
         pullrequest_title = _form['pullrequest_title']
         title_source_ref = source_ref_obj.name
         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']
         description_renderer = _form['description_renderer']
 
         try:
             pull_request = PullRequestModel().create(
                 created_by=self._rhodecode_user.user_id,
                 source_repo=source_repo,
                 source_ref=source_ref,
                 target_repo=target_repo,
                 target_ref=target_ref,
                 revisions=commit_ids,
                 common_ancestor_id=common_ancestor_id,
                 reviewers=reviewers,
                 observers=observers,
                 title=pullrequest_title,
                 description=description,
                 description_renderer=description_renderer,
                 reviewer_data=reviewer_rules,
                 auth_user=self._rhodecode_user
             )
             Session().commit()
 
             h.flash(_('Successfully opened new pull request'),
                     category='success')
         except Exception:
             msg = _('Error occurred during creation of this pull request.')
             log.exception(msg)
             h.flash(msg, category='error')
 
             # copy the args back to redirect
             org_query = self.request.GET.mixed()
             raise HTTPFound(
                 h.route_path('pullrequest_new', repo_name=self.db_repo_name,
                              _query=org_query))
 
         raise HTTPFound(
             h.route_path('pullrequest_show', repo_name=target_repo,
                          pull_request_id=pull_request.pull_request_id))
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     @CSRFRequired()
     def pull_request_update(self):
         pull_request = PullRequest.get_or_404(
             self.request.matchdict['pull_request_id'])
         _ = self.request.translate
 
         c = self.load_default_context()
         redirect_url = None
 
         if pull_request.is_closed():
             log.debug('update: forbidden because pull request is closed')
             msg = _(u'Cannot update closed pull requests.')
             h.flash(msg, category='error')
             return {'response': True,
                     'redirect_url': redirect_url}
 
         is_state_changing = pull_request.is_state_changing()
         c.pr_broadcast_channel = channelstream.pr_channel(pull_request)
 
         # only owner or admin can update it
         allowed_to_update = PullRequestModel().check_user_update(
             pull_request, self._rhodecode_user)
 
         if allowed_to_update:
             controls = peppercorn.parse(self.request.POST.items())
             force_refresh = str2bool(self.request.POST.get('force_refresh'))
 
             if 'review_members' in controls:
                 self._update_reviewers(
                     c,
                     pull_request, controls['review_members'],
                     pull_request.reviewer_data,
                     PullRequestReviewers.ROLE_REVIEWER)
             elif 'observer_members' in controls:
                 self._update_reviewers(
                     c,
                     pull_request, controls['observer_members'],
                     pull_request.reviewer_data,
                     PullRequestReviewers.ROLE_OBSERVER)
             elif str2bool(self.request.POST.get('update_commits', 'false')):
                 if is_state_changing:
                     log.debug('commits update: forbidden because pull request is in state %s',
                               pull_request.pull_request_state)
                     msg = _(u'Cannot update pull requests commits in state other than `{}`. '
                             u'Current state is: `{}`').format(
                         PullRequest.STATE_CREATED, pull_request.pull_request_state)
                     h.flash(msg, category='error')
                     return {'response': True,
                             'redirect_url': redirect_url}
 
                 self._update_commits(c, pull_request)
                 if force_refresh:
                     redirect_url = h.route_path(
                         'pullrequest_show', repo_name=self.db_repo_name,
                         pull_request_id=pull_request.pull_request_id,
                         _query={"force_refresh": 1})
             elif str2bool(self.request.POST.get('edit_pull_request', 'false')):
                 self._edit_pull_request(pull_request)
             else:
                 log.error('Unhandled update data.')
                 raise HTTPBadRequest()
 
             return {'response': True,
                     'redirect_url': redirect_url}
         raise HTTPForbidden()
 
     def _edit_pull_request(self, pull_request):
         """
         Edit title and description
         """
         _ = self.request.translate
 
         try:
             PullRequestModel().edit(
                 pull_request,
                 self.request.POST.get('title'),
                 self.request.POST.get('description'),
                 self.request.POST.get('description_renderer'),
                 self._rhodecode_user)
         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, c, pull_request):
         _ = self.request.translate
 
+        @retry(exception=Exception, n_tries=3)
+        def commits_update():
+            return PullRequestModel().update_commits(
+                pull_request, self._rhodecode_db_user)
+
         with pull_request.set_state(PullRequest.STATE_UPDATING):
-            resp = PullRequestModel().update_commits(
-                pull_request, self._rhodecode_db_user)
+            resp = commits_update()  # retry x3
 
         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'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),
                 change_source=changed)
             h.flash(msg, category='success')
             channelstream.pr_update_channelstream_push(
                 self.request, c.pr_broadcast_channel, self._rhodecode_user, msg)
         else:
             msg = PullRequestModel.UPDATE_STATUS_MESSAGES[resp.reason]
             warning_reasons = [
                 UpdateFailureReason.NO_CHANGE,
                 UpdateFailureReason.WRONG_REF_TYPE,
             ]
             category = 'warning' if resp.reason in warning_reasons else 'error'
             h.flash(msg, category=category)
 
     def _update_reviewers(self, c, pull_request, review_members, reviewer_rules, role):
         _ = self.request.translate
 
         get_default_reviewers_data, validate_default_reviewers, validate_observers = \
             PullRequestModel().get_reviewer_functions()
 
         if role == PullRequestReviewers.ROLE_REVIEWER:
             try:
                 reviewers = validate_default_reviewers(review_members, reviewer_rules)
             except ValueError as e:
                 log.error('Reviewers Validation: {}'.format(e))
                 h.flash(e, category='error')
                 return
 
             old_calculated_status = pull_request.calculated_review_status()
             PullRequestModel().update_reviewers(
                 pull_request, reviewers, self._rhodecode_db_user)
 
             Session().commit()
 
             msg = _('Pull request reviewers updated.')
             h.flash(msg, category='success')
             channelstream.pr_update_channelstream_push(
                 self.request, c.pr_broadcast_channel, self._rhodecode_user, msg)
 
             # trigger status changed if change in reviewers changes the status
             calculated_status = pull_request.calculated_review_status()
             if old_calculated_status != calculated_status:
                 PullRequestModel().trigger_pull_request_hook(
                     pull_request, self._rhodecode_user, 'review_status_change',
                     data={'status': calculated_status})
 
         elif role == PullRequestReviewers.ROLE_OBSERVER:
             try:
                 observers = validate_observers(review_members, reviewer_rules)
             except ValueError as e:
                 log.error('Observers Validation: {}'.format(e))
                 h.flash(e, category='error')
                 return
 
             PullRequestModel().update_observers(
                 pull_request, observers, self._rhodecode_db_user)
 
             Session().commit()
             msg = _('Pull request observers updated.')
             h.flash(msg, category='success')
             channelstream.pr_update_channelstream_push(
                 self.request, c.pr_broadcast_channel, self._rhodecode_user, msg)
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     @CSRFRequired()
     def pull_request_merge(self):
         """
         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 = PullRequest.get_or_404(
             self.request.matchdict['pull_request_id'])
         _ = self.request.translate
 
         if pull_request.is_state_changing():
             log.debug('show: forbidden because pull request is in state %s',
                       pull_request.pull_request_state)
             msg = _(u'Cannot merge pull requests in state other than `{}`. '
                     u'Current state is: `{}`').format(PullRequest.STATE_CREATED,
                                                       pull_request.pull_request_state)
             h.flash(msg, category='error')
             raise HTTPFound(
                 h.route_path('pullrequest_show',
                              repo_name=pull_request.target_repo.repo_name,
                              pull_request_id=pull_request.pull_request_id))
 
         self.load_default_context()
 
         with pull_request.set_state(PullRequest.STATE_UPDATING):
             check = MergeCheck.validate(
                 pull_request, auth_user=self._rhodecode_user,
                 translator=self.request.translate)
         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(
                 self.request.environ, repo_name=pull_request.target_repo.repo_name,
                 username=self._rhodecode_db_user.username, action='push',
                 scm=pull_request.target_repo.repo_type)
             with pull_request.set_state(PullRequest.STATE_UPDATING):
                 self._merge_pull_request(
                     pull_request, self._rhodecode_db_user, extras)
         else:
             log.debug("Pre-conditions failed, NOT merging.")
 
         raise HTTPFound(
             h.route_path('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):
         _ = self.request.translate
         merge_resp = PullRequestModel().merge_repo(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 = merge_resp.merge_status_message
             h.flash(msg, category='error')
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     @CSRFRequired()
     def pull_request_delete(self):
         _ = self.request.translate
 
         pull_request = PullRequest.get_or_404(
             self.request.matchdict['pull_request_id'])
         self.load_default_context()
 
         pr_closed = pull_request.is_closed()
         allowed_to_delete = PullRequestModel().check_user_delete(
             pull_request, self._rhodecode_user) and not pr_closed
 
         # only owner can delete it !
         if allowed_to_delete:
             PullRequestModel().delete(pull_request, self._rhodecode_user)
             Session().commit()
             h.flash(_('Successfully deleted pull request'),
                     category='success')
             raise HTTPFound(h.route_path('pullrequest_show_all',
                                          repo_name=self.db_repo_name))
 
         log.warning('user %s tried to delete pull request without access',
                     self._rhodecode_user)
         raise HTTPNotFound()
 
     def _pull_request_comments_create(self, pull_request, comments):
         _ = self.request.translate
         data = {}
         if not comments:
             return
         pull_request_id = pull_request.pull_request_id
 
         all_drafts = len([x for x in comments if str2bool(x['is_draft'])]) == len(comments)
 
         for entry in comments:
             c = self.load_default_context()
             comment_type = entry['comment_type']
             text = entry['text']
             status = entry['status']
             is_draft = str2bool(entry['is_draft'])
             resolves_comment_id = entry['resolves_comment_id']
             close_pull_request = entry['close_pull_request']
             f_path = entry['f_path']
             line_no = entry['line']
             target_elem_id = 'file-{}'.format(h.safeid(h.safe_unicode(f_path)))
 
             # the logic here should work like following, if we submit close
             # pr comment, use `close_pull_request_with_comment` function
             # else handle regular comment logic
 
             if close_pull_request:
                 # only owner or admin or person with write permissions
                 allowed_to_close = PullRequestModel().check_user_update(
                     pull_request, self._rhodecode_user)
                 if not allowed_to_close:
                     log.debug('comment: forbidden because not allowed to close '
                               'pull request %s', pull_request_id)
                     raise HTTPForbidden()
 
                 # This also triggers `review_status_change`
                 comment, status = PullRequestModel().close_pull_request_with_comment(
                     pull_request, self._rhodecode_user, self.db_repo, message=text,
                     auth_user=self._rhodecode_user)
                 Session().flush()
                 is_inline = comment.is_inline
 
                 PullRequestModel().trigger_pull_request_hook(
                     pull_request, self._rhodecode_user, 'comment',
                     data={'comment': comment})
 
             else:
                 # regular comment case, could be inline, or one with status.
                 # for that one we check also permissions
                 # Additionally ENSURE if somehow draft is sent we're then unable to change status
                 allowed_to_change_status = PullRequestModel().check_user_change_status(
                     pull_request, self._rhodecode_user) and not is_draft
 
                 if status and allowed_to_change_status:
                     message = (_('Status change %(transition_icon)s %(status)s')
                                % {'transition_icon': '>',
                                   'status': ChangesetStatus.get_status_lbl(status)})
                     text = text or message
 
                 comment = CommentsModel().create(
                     text=text,
                     repo=self.db_repo.repo_id,
                     user=self._rhodecode_user.user_id,
                     pull_request=pull_request,
                     f_path=f_path,
                     line_no=line_no,
                     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),
                     comment_type=comment_type,
                     is_draft=is_draft,
                     resolves_comment_id=resolves_comment_id,
                     auth_user=self._rhodecode_user,
                     send_email=not is_draft,  # skip notification for draft comments
                 )
                 is_inline = comment.is_inline
 
                 if allowed_to_change_status:
                     # calculate old status before we change it
                     old_calculated_status = pull_request.calculated_review_status()
 
                     # get status if set !
                     if status:
                         ChangesetStatusModel().set_status(
                             self.db_repo.repo_id,
                             status,
                             self._rhodecode_user.user_id,
                             comment,
                             pull_request=pull_request
                         )
 
                     Session().flush()
                     # this is somehow required to get access to some relationship
                     # loaded on comment
                     Session().refresh(comment)
 
                     # skip notifications for drafts
                     if not is_draft:
                         PullRequestModel().trigger_pull_request_hook(
                             pull_request, self._rhodecode_user, 'comment',
                             data={'comment': comment})
 
                     # 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, self._rhodecode_user, 'review_status_change',
                             data={'status': calculated_status})
 
             comment_id = comment.comment_id
             data[comment_id] = {
                 'target_id': target_elem_id
             }
             Session().flush()
 
             c.co = comment
             c.at_version_num = None
             c.is_new = True
             rendered_comment = render(
                 'rhodecode:templates/changeset/changeset_comment_block.mako',
                 self._get_template_context(c), self.request)
 
             data[comment_id].update(comment.get_dict())
             data[comment_id].update({'rendered_text': rendered_comment})
 
         Session().commit()
 
         # skip channelstream for draft comments
         if not all_drafts:
             comment_broadcast_channel = channelstream.comment_channel(
                 self.db_repo_name, pull_request_obj=pull_request)
 
             comment_data = data
             posted_comment_type = 'inline' if is_inline else 'general'
             if len(data) == 1:
                 msg = _('posted {} new {} comment').format(len(data), posted_comment_type)
             else:
                 msg = _('posted {} new {} comments').format(len(data), posted_comment_type)
 
             channelstream.comment_channelstream_push(
                 self.request, comment_broadcast_channel, self._rhodecode_user, msg,
                 comment_data=comment_data)
 
         return data
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     @CSRFRequired()
     def pull_request_comment_create(self):
         _ = self.request.translate
 
         pull_request = PullRequest.get_or_404(self.request.matchdict['pull_request_id'])
 
         if pull_request.is_closed():
             log.debug('comment: forbidden because pull request is closed')
             raise HTTPForbidden()
 
         allowed_to_comment = PullRequestModel().check_user_comment(
             pull_request, self._rhodecode_user)
         if not allowed_to_comment:
             log.debug('comment: forbidden because pull request is from forbidden repo')
             raise HTTPForbidden()
 
         comment_data = {
             'comment_type': self.request.POST.get('comment_type'),
             'text': self.request.POST.get('text'),
             'status': self.request.POST.get('changeset_status', None),
             'is_draft': self.request.POST.get('draft'),
             'resolves_comment_id': self.request.POST.get('resolves_comment_id', None),
             'close_pull_request': self.request.POST.get('close_pull_request'),
             'f_path': self.request.POST.get('f_path'),
             'line': self.request.POST.get('line'),
         }
         data = self._pull_request_comments_create(pull_request, [comment_data])
 
         return data
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     @CSRFRequired()
     def pull_request_comment_delete(self):
         pull_request = PullRequest.get_or_404(
             self.request.matchdict['pull_request_id'])
 
         comment = ChangesetComment.get_or_404(
             self.request.matchdict['comment_id'])
         comment_id = comment.comment_id
 
         if comment.immutable:
             # don't allow deleting comments that are immutable
             raise HTTPForbidden()
 
         if pull_request.is_closed():
             log.debug('comment: forbidden because pull request is closed')
             raise HTTPForbidden()
 
         if not comment:
             log.debug('Comment with id:%s not found, skipping', comment_id)
             # comment already deleted in another call probably
             return True
 
         if comment.pull_request.is_closed():
             # don't allow deleting comments on closed pull request
             raise HTTPForbidden()
 
         is_repo_admin = h.HasRepoPermissionAny('repository.admin')(self.db_repo_name)
         super_admin = h.HasPermissionAny('hg.admin')()
         comment_owner = comment.author.user_id == self._rhodecode_user.user_id
         is_repo_comment = comment.repo.repo_name == self.db_repo_name
         comment_repo_admin = is_repo_admin and is_repo_comment
 
         if comment.draft and not comment_owner:
             # We never allow to delete draft comments for other than owners
             raise HTTPNotFound()
 
         if super_admin or comment_owner or comment_repo_admin:
             old_calculated_status = comment.pull_request.calculated_review_status()
             CommentsModel().delete(comment=comment, auth_user=self._rhodecode_user)
             Session().commit()
             calculated_status = comment.pull_request.calculated_review_status()
             if old_calculated_status != calculated_status:
                 PullRequestModel().trigger_pull_request_hook(
                     comment.pull_request, self._rhodecode_user, 'review_status_change',
                     data={'status': calculated_status})
             return True
         else:
             log.warning('No permissions for user %s to delete comment_id: %s',
                         self._rhodecode_db_user, comment_id)
             raise HTTPNotFound()
 
     @LoginRequired()
     @NotAnonymous()
     @HasRepoPermissionAnyDecorator(
         'repository.read', 'repository.write', 'repository.admin')
     @CSRFRequired()
     def pull_request_comment_edit(self):
         self.load_default_context()
 
         pull_request = PullRequest.get_or_404(
             self.request.matchdict['pull_request_id']
         )
         comment = ChangesetComment.get_or_404(
             self.request.matchdict['comment_id']
         )
         comment_id = comment.comment_id
 
         if comment.immutable:
             # don't allow deleting comments that are immutable
             raise HTTPForbidden()
 
         if pull_request.is_closed():
             log.debug('comment: forbidden because pull request is closed')
             raise HTTPForbidden()
 
         if comment.pull_request.is_closed():
             # don't allow deleting comments on closed pull request
             raise HTTPForbidden()
 
         is_repo_admin = h.HasRepoPermissionAny('repository.admin')(self.db_repo_name)
         super_admin = h.HasPermissionAny('hg.admin')()
         comment_owner = comment.author.user_id == self._rhodecode_user.user_id
         is_repo_comment = comment.repo.repo_name == self.db_repo_name
         comment_repo_admin = is_repo_admin and is_repo_comment
 
         if super_admin or comment_owner or comment_repo_admin:
             text = self.request.POST.get('text')
             version = self.request.POST.get('version')
             if text == comment.text:
                 log.warning(
                     'Comment(PR): '
                     'Trying to create new version '
                     'with the same comment body {}'.format(
                         comment_id,
                     )
                 )
                 raise HTTPNotFound()
 
             if version.isdigit():
                 version = int(version)
             else:
                 log.warning(
                     'Comment(PR): Wrong version type {} {} '
                     'for comment {}'.format(
                         version,
                         type(version),
                         comment_id,
                     )
                 )
                 raise HTTPNotFound()
 
             try:
                 comment_history = CommentsModel().edit(
                     comment_id=comment_id,
                     text=text,
                     auth_user=self._rhodecode_user,
                     version=version,
                 )
             except CommentVersionMismatch:
                 raise HTTPConflict()
 
             if not comment_history:
                 raise HTTPNotFound()
 
             Session().commit()
             if not comment.draft:
                 PullRequestModel().trigger_pull_request_hook(
                     pull_request, self._rhodecode_user, 'comment_edit',
                     data={'comment': comment})
 
             return {
                 'comment_history_id': comment_history.comment_history_id,
                 'comment_id': comment.comment_id,
                 'comment_version': comment_history.version,
                 'comment_author_username': comment_history.author.username,
                 'comment_author_gravatar': h.gravatar_url(comment_history.author.email, 16),
                 'comment_created_on': h.age_component(comment_history.created_on,
                                                       time_is_local=True),
             }
         else:
             log.warning('No permissions for user %s to edit comment_id: %s',
                         self._rhodecode_db_user, comment_id)
             raise HTTPNotFound()

rhodecode/lib/utils2.py

@@ -1,1074 +1,1148 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2011-2020 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/
 
 
 """
 Some simple helper functions
 """
 
 import collections
 import datetime
 import dateutil.relativedelta
 import hashlib
 import logging
 import re
 import sys
 import time
 import urllib
 import urlobject
 import uuid
 import getpass
-from functools import update_wrapper, partial
+from functools import update_wrapper, partial, wraps
 
 import pygments.lexers
 import sqlalchemy
 import sqlalchemy.engine.url
 import sqlalchemy.exc
 import sqlalchemy.sql
 import webob
 import pyramid.threadlocal
 from pyramid import compat
 from pyramid.settings import asbool
 
 import rhodecode
 from rhodecode.translation import _, _pluralize
 
 
 def md5(s):
     return hashlib.md5(s).hexdigest()
 
 
 def md5_safe(s):
     return md5(safe_str(s))
 
 
 def sha1(s):
     return hashlib.sha1(s).hexdigest()
 
 
 def sha1_safe(s):
     return sha1(safe_str(s))
 
 
 def __get_lem(extra_mapping=None):
     """
     Get language extension map based on what's inside pygments lexers
     """
     d = collections.defaultdict(lambda: [])
 
     def __clean(s):
         s = s.lstrip('*')
         s = s.lstrip('.')
 
         if s.find('[') != -1:
             exts = []
             start, stop = s.find('['), s.find(']')
 
             for suffix in s[start + 1:stop]:
                 exts.append(s[:s.find('[')] + suffix)
             return [e.lower() for e in exts]
         else:
             return [s.lower()]
 
     for lx, t in sorted(pygments.lexers.LEXERS.items()):
         m = map(__clean, t[-2])
         if m:
             m = reduce(lambda x, y: x + y, m)
             for ext in m:
                 desc = lx.replace('Lexer', '')
                 d[ext].append(desc)
 
     data = dict(d)
 
     extra_mapping = extra_mapping or {}
     if extra_mapping:
         for k, v in extra_mapping.items():
             if k not in data:
                 # register new mapping2lexer
                 data[k] = [v]
 
     return data
 
 
 def str2bool(_str):
     """
     returns True/False value from given string, it tries to translate the
     string into boolean
 
     :param _str: string value to translate into boolean
     :rtype: boolean
     :returns: boolean from given string
     """
     if _str is None:
         return False
     if _str in (True, False):
         return _str
     _str = str(_str).strip().lower()
     return _str in ('t', 'true', 'y', 'yes', 'on', '1')
 
 
 def aslist(obj, sep=None, strip=True):
     """
     Returns given string separated by sep as list
 
     :param obj:
     :param sep:
     :param strip:
     """
     if isinstance(obj, (basestring,)):
         lst = obj.split(sep)
         if strip:
             lst = [v.strip() for v in lst]
         return lst
     elif isinstance(obj, (list, tuple)):
         return obj
     elif obj is None:
         return []
     else:
         return [obj]
 
 
 def convert_line_endings(line, mode):
     """
     Converts a given line  "line end" accordingly to given mode
 
     Available modes are::
         0 - Unix
         1 - Mac
         2 - DOS
 
     :param line: given line to convert
     :param mode: mode to convert to
     :rtype: str
     :return: converted line according to mode
     """
     if mode == 0:
         line = line.replace('\r\n', '\n')
         line = line.replace('\r', '\n')
     elif mode == 1:
         line = line.replace('\r\n', '\r')
         line = line.replace('\n', '\r')
     elif mode == 2:
         line = re.sub('\r(?!\n)|(?<!\r)\n', '\r\n', line)
     return line
 
 
 def detect_mode(line, default):
     """
     Detects line break for given line, if line break couldn't be found
     given default value is returned
 
     :param line: str line
     :param default: default
     :rtype: int
     :return: value of line end on of 0 - Unix, 1 - Mac, 2 - DOS
     """
     if line.endswith('\r\n'):
         return 2
     elif line.endswith('\n'):
         return 0
     elif line.endswith('\r'):
         return 1
     else:
         return default
 
 
 def safe_int(val, default=None):
     """
     Returns int() of val if val is not convertable to int use default
     instead
 
     :param val:
     :param default:
     """
 
     try:
         val = int(val)
     except (ValueError, TypeError):
         val = default
 
     return val
 
 
 def safe_unicode(str_, from_encoding=None, use_chardet=False):
     """
     safe unicode function. Does few trick to turn str_ into unicode
 
     In case of UnicodeDecode error, we try to return it with encoding detected
     by chardet library if it fails fallback to unicode with errors replaced
 
     :param str_: string to decode
     :rtype: unicode
     :returns: unicode object
     """
     if isinstance(str_, unicode):
         return str_
 
     if not from_encoding:
         DEFAULT_ENCODINGS = aslist(rhodecode.CONFIG.get('default_encoding',
                                                         'utf8'), sep=',')
         from_encoding = DEFAULT_ENCODINGS
 
     if not isinstance(from_encoding, (list, tuple)):
         from_encoding = [from_encoding]
 
     try:
         return unicode(str_)
     except UnicodeDecodeError:
         pass
 
     for enc in from_encoding:
         try:
             return unicode(str_, enc)
         except UnicodeDecodeError:
             pass
 
     if use_chardet:
         try:
             import chardet
             encoding = chardet.detect(str_)['encoding']
             if encoding is None:
                 raise Exception()
             return str_.decode(encoding)
         except (ImportError, UnicodeDecodeError, Exception):
             return unicode(str_, from_encoding[0], 'replace')
     else:
         return unicode(str_, from_encoding[0], 'replace')
 
 def safe_str(unicode_, to_encoding=None, use_chardet=False):
     """
     safe str function. Does few trick to turn unicode_ into string
 
     In case of UnicodeEncodeError, we try to return it with encoding detected
     by chardet library if it fails fallback to string with errors replaced
 
     :param unicode_: unicode to encode
     :rtype: str
     :returns: str object
     """
 
     # if it's not basestr cast to str
     if not isinstance(unicode_, compat.string_types):
         return str(unicode_)
 
     if isinstance(unicode_, str):
         return unicode_
 
     if not to_encoding:
         DEFAULT_ENCODINGS = aslist(rhodecode.CONFIG.get('default_encoding',
                                                         'utf8'), sep=',')
         to_encoding = DEFAULT_ENCODINGS
 
     if not isinstance(to_encoding, (list, tuple)):
         to_encoding = [to_encoding]
 
     for enc in to_encoding:
         try:
             return unicode_.encode(enc)
         except UnicodeEncodeError:
             pass
 
     if use_chardet:
         try:
             import chardet
             encoding = chardet.detect(unicode_)['encoding']
             if encoding is None:
                 raise UnicodeEncodeError()
 
             return unicode_.encode(encoding)
         except (ImportError, UnicodeEncodeError):
             return unicode_.encode(to_encoding[0], 'replace')
     else:
         return unicode_.encode(to_encoding[0], 'replace')
 
 
 def remove_suffix(s, suffix):
     if s.endswith(suffix):
         s = s[:-1 * len(suffix)]
     return s
 
 
 def remove_prefix(s, prefix):
     if s.startswith(prefix):
         s = s[len(prefix):]
     return s
 
 
 def find_calling_context(ignore_modules=None):
     """
     Look through the calling stack and return the frame which called
     this function and is part of core module ( ie. rhodecode.* )
 
     :param ignore_modules: list of modules to ignore eg. ['rhodecode.lib']
     """
 
     ignore_modules = ignore_modules or []
 
     f = sys._getframe(2)
     while f.f_back is not None:
         name = f.f_globals.get('__name__')
         if name and name.startswith(__name__.split('.')[0]):
             if name not in ignore_modules:
                 return f
         f = f.f_back
     return None
 
 
 def ping_connection(connection, branch):
     if branch:
         # "branch" refers to a sub-connection of a connection,
         # we don't want to bother pinging on these.
         return
 
     # turn off "close with result".  This flag is only used with
     # "connectionless" execution, otherwise will be False in any case
     save_should_close_with_result = connection.should_close_with_result
     connection.should_close_with_result = False
 
     try:
         # run a SELECT 1.   use a core select() so that
         # the SELECT of a scalar value without a table is
         # appropriately formatted for the backend
         connection.scalar(sqlalchemy.sql.select([1]))
     except sqlalchemy.exc.DBAPIError as err:
         # catch SQLAlchemy's DBAPIError, which is a wrapper
         # for the DBAPI's exception.  It includes a .connection_invalidated
         # attribute which specifies if this connection is a "disconnect"
         # condition, which is based on inspection of the original exception
         # by the dialect in use.
         if err.connection_invalidated:
             # run the same SELECT again - the connection will re-validate
             # itself and establish a new connection.  The disconnect detection
             # here also causes the whole connection pool to be invalidated
             # so that all stale connections are discarded.
             connection.scalar(sqlalchemy.sql.select([1]))
         else:
             raise
     finally:
         # restore "close with result"
         connection.should_close_with_result = save_should_close_with_result
 
 
 def engine_from_config(configuration, prefix='sqlalchemy.', **kwargs):
     """Custom engine_from_config functions."""
     log = logging.getLogger('sqlalchemy.engine')
     use_ping_connection = asbool(configuration.pop('sqlalchemy.db1.ping_connection', None))
     debug = asbool(configuration.pop('sqlalchemy.db1.debug_query', None))
 
     engine = sqlalchemy.engine_from_config(configuration, prefix, **kwargs)
 
     def color_sql(sql):
         color_seq = '\033[1;33m'  # This is yellow: code 33
         normal = '\x1b[0m'
         return ''.join([color_seq, sql, normal])
 
     if use_ping_connection:
         log.debug('Adding ping_connection on the engine config.')
         sqlalchemy.event.listen(engine, "engine_connect", ping_connection)
 
     if debug:
         # attach events only for debug configuration
         def before_cursor_execute(conn, cursor, statement,
                                   parameters, context, executemany):
             setattr(conn, 'query_start_time', time.time())
             log.info(color_sql(">>>>> STARTING QUERY >>>>>"))
             calling_context = find_calling_context(ignore_modules=[
                 'rhodecode.lib.caching_query',
                 'rhodecode.model.settings',
             ])
             if calling_context:
                 log.info(color_sql('call context %s:%s' % (
                     calling_context.f_code.co_filename,
                     calling_context.f_lineno,
                 )))
 
         def after_cursor_execute(conn, cursor, statement,
                                  parameters, context, executemany):
             delattr(conn, 'query_start_time')
 
         sqlalchemy.event.listen(engine, "before_cursor_execute", before_cursor_execute)
         sqlalchemy.event.listen(engine, "after_cursor_execute", after_cursor_execute)
 
     return engine
 
 
 def get_encryption_key(config):
     secret = config.get('rhodecode.encrypted_values.secret')
     default = config['beaker.session.secret']
     return secret or default
 
 
 def age(prevdate, now=None, show_short_version=False, show_suffix=True,
         short_format=False):
     """
     Turns a datetime into an age string.
     If show_short_version is True, this generates a shorter string with
     an approximate age; ex. '1 day ago', rather than '1 day and 23 hours ago'.
 
     * IMPORTANT*
     Code of this function is written in special way so it's easier to
     backport it to javascript. If you mean to update it, please also update
     `jquery.timeago-extension.js` file
 
     :param prevdate: datetime object
     :param now: get current time, if not define we use
         `datetime.datetime.now()`
     :param show_short_version: if it should approximate the date and
         return a shorter string
     :param show_suffix:
     :param short_format: show short format, eg 2D instead of 2 days
     :rtype: unicode
     :returns: unicode words describing age
     """
 
     def _get_relative_delta(now, prevdate):
         base = dateutil.relativedelta.relativedelta(now, prevdate)
         return {
             'year': base.years,
             'month': base.months,
             'day': base.days,
             'hour': base.hours,
             'minute': base.minutes,
             'second': base.seconds,
         }
 
     def _is_leap_year(year):
         return year % 4 == 0 and (year % 100 != 0 or year % 400 == 0)
 
     def get_month(prevdate):
         return prevdate.month
 
     def get_year(prevdate):
         return prevdate.year
 
     now = now or datetime.datetime.now()
     order = ['year', 'month', 'day', 'hour', 'minute', 'second']
     deltas = {}
     future = False
 
     if prevdate > now:
         now_old = now
         now = prevdate
         prevdate = now_old
         future = True
     if future:
         prevdate = prevdate.replace(microsecond=0)
     # Get date parts deltas
     for part in order:
         rel_delta = _get_relative_delta(now, prevdate)
         deltas[part] = rel_delta[part]
 
     # Fix negative offsets (there is 1 second between 10:59:59 and 11:00:00,
     # not 1 hour, -59 minutes and -59 seconds)
     offsets = [[5, 60], [4, 60], [3, 24]]
     for element in offsets:  # seconds, minutes, hours
         num = element[0]
         length = element[1]
 
         part = order[num]
         carry_part = order[num - 1]
 
         if deltas[part] < 0:
             deltas[part] += length
             deltas[carry_part] -= 1
 
     # Same thing for days except that the increment depends on the (variable)
     # number of days in the month
     month_lengths = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
     if deltas['day'] < 0:
         if get_month(prevdate) == 2 and _is_leap_year(get_year(prevdate)):
             deltas['day'] += 29
         else:
             deltas['day'] += month_lengths[get_month(prevdate) - 1]
 
         deltas['month'] -= 1
 
     if deltas['month'] < 0:
         deltas['month'] += 12
         deltas['year'] -= 1
 
     # Format the result
     if short_format:
         fmt_funcs = {
             'year': lambda d: u'%dy' % d,
             'month': lambda d: u'%dm' % d,
             'day': lambda d: u'%dd' % d,
             'hour': lambda d: u'%dh' % d,
             'minute': lambda d: u'%dmin' % d,
             'second': lambda d: u'%dsec' % d,
         }
     else:
         fmt_funcs = {
             'year': lambda d: _pluralize(u'${num} year', u'${num} years', d, mapping={'num': d}).interpolate(),
             'month': lambda d: _pluralize(u'${num} month', u'${num} months', d, mapping={'num': d}).interpolate(),
             'day': lambda d: _pluralize(u'${num} day', u'${num} days', d, mapping={'num': d}).interpolate(),
             'hour': lambda d: _pluralize(u'${num} hour', u'${num} hours', d, mapping={'num': d}).interpolate(),
             'minute': lambda d: _pluralize(u'${num} minute', u'${num} minutes', d, mapping={'num': d}).interpolate(),
             'second': lambda d: _pluralize(u'${num} second', u'${num} seconds', d, mapping={'num': d}).interpolate(),
         }
 
     i = 0
     for part in order:
         value = deltas[part]
         if value != 0:
 
             if i < 5:
                 sub_part = order[i + 1]
                 sub_value = deltas[sub_part]
             else:
                 sub_value = 0
 
             if sub_value == 0 or show_short_version:
                 _val = fmt_funcs[part](value)
                 if future:
                     if show_suffix:
                         return _(u'in ${ago}', mapping={'ago': _val})
                     else:
                         return _(_val)
 
                 else:
                     if show_suffix:
                         return _(u'${ago} ago', mapping={'ago': _val})
                     else:
                         return _(_val)
 
             val = fmt_funcs[part](value)
             val_detail = fmt_funcs[sub_part](sub_value)
             mapping = {'val': val, 'detail': val_detail}
 
             if short_format:
                 datetime_tmpl = _(u'${val}, ${detail}', mapping=mapping)
                 if show_suffix:
                     datetime_tmpl = _(u'${val}, ${detail} ago', mapping=mapping)
                     if future:
                         datetime_tmpl = _(u'in ${val}, ${detail}', mapping=mapping)
             else:
                 datetime_tmpl = _(u'${val} and ${detail}', mapping=mapping)
                 if show_suffix:
                     datetime_tmpl = _(u'${val} and ${detail} ago', mapping=mapping)
                     if future:
                         datetime_tmpl = _(u'in ${val} and ${detail}', mapping=mapping)
 
             return datetime_tmpl
         i += 1
     return _(u'just now')
 
 
 def age_from_seconds(seconds):
     seconds = safe_int(seconds) or 0
     prevdate = time_to_datetime(time.time() + seconds)
     return age(prevdate, show_suffix=False, show_short_version=True)
 
 
 def cleaned_uri(uri):
     """
     Quotes '[' and ']' from uri if there is only one of them.
         according to RFC3986 we cannot use such chars in uri
     :param uri:
     :return: uri without this chars
     """
     return urllib.quote(uri, safe='@$:/')
 
 
 def credentials_filter(uri):
     """
     Returns a url with removed credentials
 
     :param uri:
     """
     import urlobject
     if isinstance(uri, rhodecode.lib.encrypt.InvalidDecryptedValue):
         return 'InvalidDecryptionKey'
 
     url_obj = urlobject.URLObject(cleaned_uri(uri))
     url_obj = url_obj.without_password().without_username()
 
     return url_obj
 
 
 def get_host_info(request):
     """
     Generate host info, to obtain full url e.g https://server.com
     use this
     `{scheme}://{netloc}`
     """
     if not request:
         return {}
 
     qualified_home_url = request.route_url('home')
     parsed_url = urlobject.URLObject(qualified_home_url)
     decoded_path = safe_unicode(urllib.unquote(parsed_url.path.rstrip('/')))
 
     return {
         'scheme': parsed_url.scheme,
         'netloc': parsed_url.netloc+decoded_path,
         'hostname': parsed_url.hostname,
     }
 
 
 def get_clone_url(request, uri_tmpl, repo_name, repo_id, repo_type, **override):
     qualified_home_url = request.route_url('home')
     parsed_url = urlobject.URLObject(qualified_home_url)
     decoded_path = safe_unicode(urllib.unquote(parsed_url.path.rstrip('/')))
 
     args = {
         'scheme': parsed_url.scheme,
         'user': '',
         'sys_user': getpass.getuser(),
         # path if we use proxy-prefix
         'netloc': parsed_url.netloc+decoded_path,
         'hostname': parsed_url.hostname,
         'prefix': decoded_path,
         'repo': repo_name,
         'repoid': str(repo_id),
         'repo_type': repo_type
     }
     args.update(override)
     args['user'] = urllib.quote(safe_str(args['user']))
 
     for k, v in args.items():
         uri_tmpl = uri_tmpl.replace('{%s}' % k, v)
 
     # special case for SVN clone url
     if repo_type == 'svn':
         uri_tmpl = uri_tmpl.replace('ssh://', 'svn+ssh://')
 
     # remove leading @ sign if it's present. Case of empty user
     url_obj = urlobject.URLObject(uri_tmpl)
     url = url_obj.with_netloc(url_obj.netloc.lstrip('@'))
 
     return safe_unicode(url)
 
 
 def get_commit_safe(repo, commit_id=None, commit_idx=None, pre_load=None,
                     maybe_unreachable=False, reference_obj=None):
     """
     Safe version of get_commit if this commit doesn't exists for a
     repository it returns a Dummy one instead
 
     :param repo: repository instance
     :param commit_id: commit id as str
     :param commit_idx: numeric commit index
     :param pre_load: optional list of commit attributes to load
     :param maybe_unreachable: translate unreachable commits on git repos
     :param reference_obj: explicitly search via a reference obj in git. E.g "branch:123" would mean branch "123"
     """
     # TODO(skreft): remove these circular imports
     from rhodecode.lib.vcs.backends.base import BaseRepository, EmptyCommit
     from rhodecode.lib.vcs.exceptions import RepositoryError
     if not isinstance(repo, BaseRepository):
         raise Exception('You must pass an Repository '
                         'object as first argument got %s', type(repo))
 
     try:
         commit = repo.get_commit(
             commit_id=commit_id, commit_idx=commit_idx, pre_load=pre_load,
             maybe_unreachable=maybe_unreachable, reference_obj=reference_obj)
     except (RepositoryError, LookupError):
         commit = EmptyCommit()
     return commit
 
 
 def datetime_to_time(dt):
     if dt:
         return time.mktime(dt.timetuple())
 
 
 def time_to_datetime(tm):
     if tm:
         if isinstance(tm, compat.string_types):
             try:
                 tm = float(tm)
             except ValueError:
                 return
         return datetime.datetime.fromtimestamp(tm)
 
 
 def time_to_utcdatetime(tm):
     if tm:
         if isinstance(tm, compat.string_types):
             try:
                 tm = float(tm)
             except ValueError:
                 return
         return datetime.datetime.utcfromtimestamp(tm)
 
 
 MENTIONS_REGEX = re.compile(
     # ^@ or @ without any special chars in front
     r'(?:^@|[^a-zA-Z0-9\-\_\.]@)'
     # main body starts with letter, then can be . - _
     r'([a-zA-Z0-9]{1}[a-zA-Z0-9\-\_\.]+)',
     re.VERBOSE | re.MULTILINE)
 
 
 def extract_mentioned_users(s):
     """
     Returns unique usernames from given string s that have @mention
 
     :param s: string to get mentions
     """
     usrs = set()
     for username in MENTIONS_REGEX.findall(s):
         usrs.add(username)
 
     return sorted(list(usrs), key=lambda k: k.lower())
 
 
 class AttributeDictBase(dict):
     def __getstate__(self):
         odict = self.__dict__  # get attribute dictionary
         return odict
 
     def __setstate__(self, dict):
         self.__dict__ = dict
 
     __setattr__ = dict.__setitem__
     __delattr__ = dict.__delitem__
 
 
 class StrictAttributeDict(AttributeDictBase):
     """
     Strict Version of Attribute dict which raises an Attribute error when
     requested attribute is not set
     """
     def __getattr__(self, attr):
         try:
             return self[attr]
         except KeyError:
             raise AttributeError('%s object has no attribute %s' % (
                 self.__class__, attr))
 
 
 class AttributeDict(AttributeDictBase):
     def __getattr__(self, attr):
         return self.get(attr, None)
 
 
 
 class OrderedDefaultDict(collections.OrderedDict, collections.defaultdict):
     def __init__(self, default_factory=None, *args, **kwargs):
         # in python3 you can omit the args to super
         super(OrderedDefaultDict, self).__init__(*args, **kwargs)
         self.default_factory = default_factory
 
 
 def fix_PATH(os_=None):
     """
     Get current active python path, and append it to PATH variable to fix
     issues of subprocess calls and different python versions
     """
     if os_ is None:
         import os
     else:
         os = os_
 
     cur_path = os.path.split(sys.executable)[0]
     if not os.environ['PATH'].startswith(cur_path):
         os.environ['PATH'] = '%s:%s' % (cur_path, os.environ['PATH'])
 
 
 def obfuscate_url_pw(engine):
     _url = engine or ''
     try:
         _url = sqlalchemy.engine.url.make_url(engine)
         if _url.password:
             _url.password = 'XXXXX'
     except Exception:
         pass
     return unicode(_url)
 
 
 def get_server_url(environ):
     req = webob.Request(environ)
     return req.host_url + req.script_name
 
 
 def unique_id(hexlen=32):
     alphabet = "23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghjklmnpqrstuvwxyz"
     return suuid(truncate_to=hexlen, alphabet=alphabet)
 
 
 def suuid(url=None, truncate_to=22, alphabet=None):
     """
     Generate and return a short URL safe UUID.
 
     If the url parameter is provided, set the namespace to the provided
     URL and generate a UUID.
 
     :param url to get the uuid for
     :truncate_to: truncate the basic 22 UUID to shorter version
 
     The IDs won't be universally unique any longer, but the probability of
     a collision will still be very low.
     """
     # Define our alphabet.
     _ALPHABET = alphabet or "23456789ABCDEFGHJKLMNPQRSTUVWXYZ"
 
     # If no URL is given, generate a random UUID.
     if url is None:
         unique_id = uuid.uuid4().int
     else:
         unique_id = uuid.uuid3(uuid.NAMESPACE_URL, url).int
 
     alphabet_length = len(_ALPHABET)
     output = []
     while unique_id > 0:
         digit = unique_id % alphabet_length
         output.append(_ALPHABET[digit])
         unique_id = int(unique_id / alphabet_length)
     return "".join(output)[:truncate_to]
 
 
 def get_current_rhodecode_user(request=None):
     """
     Gets rhodecode user from request
     """
     pyramid_request = request or pyramid.threadlocal.get_current_request()
 
     # web case
     if pyramid_request and hasattr(pyramid_request, 'user'):
         return pyramid_request.user
 
     # api case
     if pyramid_request and hasattr(pyramid_request, 'rpc_user'):
         return pyramid_request.rpc_user
 
     return None
 
 
 def action_logger_generic(action, namespace=''):
     """
     A generic logger for actions useful to the system overview, tries to find
     an acting user for the context of the call otherwise reports unknown user
 
     :param action: logging message eg 'comment 5 deleted'
     :param type: string
 
     :param namespace: namespace of the logging message eg. 'repo.comments'
     :param type: string
 
     """
 
     logger_name = 'rhodecode.actions'
 
     if namespace:
         logger_name += '.' + namespace
 
     log = logging.getLogger(logger_name)
 
     # get a user if we can
     user = get_current_rhodecode_user()
 
     logfunc = log.info
 
     if not user:
         user = '<unknown user>'
         logfunc = log.warning
 
     logfunc('Logging action by {}: {}'.format(user, action))
 
 
 def escape_split(text, sep=',', maxsplit=-1):
     r"""
     Allows for escaping of the separator: e.g. arg='foo\, bar'
 
     It should be noted that the way bash et. al. do command line parsing, those
     single quotes are required.
     """
     escaped_sep = r'\%s' % sep
 
     if escaped_sep not in text:
         return text.split(sep, maxsplit)
 
     before, _mid, after = text.partition(escaped_sep)
     startlist = before.split(sep, maxsplit)  # a regular split is fine here
     unfinished = startlist[-1]
     startlist = startlist[:-1]
 
     # recurse because there may be more escaped separators
     endlist = escape_split(after, sep, maxsplit)
 
     # finish building the escaped value. we use endlist[0] becaue the first
     # part of the string sent in recursion is the rest of the escaped value.
     unfinished += sep + endlist[0]
 
     return startlist + [unfinished] + endlist[1:]  # put together all the parts
 
 
 class OptionalAttr(object):
     """
     Special Optional Option that defines other attribute. Example::
 
         def test(apiuser, userid=Optional(OAttr('apiuser')):
             user = Optional.extract(userid)
             # calls
 
     """
 
     def __init__(self, attr_name):
         self.attr_name = attr_name
 
     def __repr__(self):
         return '<OptionalAttr:%s>' % self.attr_name
 
     def __call__(self):
         return self
 
 
 # alias
 OAttr = OptionalAttr
 
 
 class Optional(object):
     """
     Defines an optional parameter::
 
         param = param.getval() if isinstance(param, Optional) else param
         param = param() if isinstance(param, Optional) else param
 
     is equivalent of::
 
         param = Optional.extract(param)
 
     """
 
     def __init__(self, type_):
         self.type_ = type_
 
     def __repr__(self):
         return '<Optional:%s>' % self.type_.__repr__()
 
     def __call__(self):
         return self.getval()
 
     def getval(self):
         """
         returns value from this Optional instance
         """
         if isinstance(self.type_, OAttr):
             # use params name
             return self.type_.attr_name
         return self.type_
 
     @classmethod
     def extract(cls, val):
         """
         Extracts value from Optional() instance
 
         :param val:
         :return: original value if it's not Optional instance else
             value of instance
         """
         if isinstance(val, cls):
             return val.getval()
         return val
 
 
 def glob2re(pat):
     """
     Translate a shell PATTERN to a regular expression.
 
     There is no way to quote meta-characters.
     """
 
     i, n = 0, len(pat)
     res = ''
     while i < n:
         c = pat[i]
         i = i+1
         if c == '*':
             #res = res + '.*'
             res = res + '[^/]*'
         elif c == '?':
             #res = res + '.'
             res = res + '[^/]'
         elif c == '[':
             j = i
             if j < n and pat[j] == '!':
                 j = j+1
             if j < n and pat[j] == ']':
                 j = j+1
             while j < n and pat[j] != ']':
                 j = j+1
             if j >= n:
                 res = res + '\\['
             else:
                 stuff = pat[i:j].replace('\\','\\\\')
                 i = j+1
                 if stuff[0] == '!':
                     stuff = '^' + stuff[1:]
                 elif stuff[0] == '^':
                     stuff = '\\' + stuff
                 res = '%s[%s]' % (res, stuff)
         else:
             res = res + re.escape(c)
     return res + '\Z(?ms)'
 
 
 def parse_byte_string(size_str):
     match = re.match(r'(\d+)(MB|KB)', size_str, re.IGNORECASE)
     if not match:
         raise ValueError('Given size:%s is invalid, please make sure '
                          'to use format of <num>(MB|KB)' % size_str)
 
     _parts = match.groups()
     num, type_ = _parts
     return long(num) * {'mb': 1024*1024, 'kb': 1024}[type_.lower()]
 
 
 class CachedProperty(object):
     """
     Lazy Attributes. With option to invalidate the cache by running a method
 
-    class Foo():
+    >>> class Foo(object):
+    ...
+    ...    @CachedProperty
+    ...    def heavy_func(self):
+    ...        return 'super-calculation'
+    ...
+    ... foo = Foo()
+    ... foo.heavy_func() # first computation
+    ... foo.heavy_func() # fetch from cache
+    ... foo._invalidate_prop_cache('heavy_func')
 
-        @CachedProperty
-        def heavy_func():
-            return 'super-calculation'
-
-    foo = Foo()
-    foo.heavy_func() # first computions
-    foo.heavy_func() # fetch from cache
-    foo._invalidate_prop_cache('heavy_func')
     # at this point calling foo.heavy_func() will be re-computed
     """
 
     def __init__(self, func, func_name=None):
 
         if func_name is None:
             func_name = func.__name__
         self.data = (func, func_name)
         update_wrapper(self, func)
 
     def __get__(self, inst, class_):
         if inst is None:
             return self
 
         func, func_name = self.data
         value = func(inst)
         inst.__dict__[func_name] = value
         if '_invalidate_prop_cache' not in inst.__dict__:
             inst.__dict__['_invalidate_prop_cache'] = partial(
                 self._invalidate_prop_cache, inst)
         return value
 
     def _invalidate_prop_cache(self, inst, name):
         inst.__dict__.pop(name, None)
+
+
+def retry(func=None, exception=Exception, n_tries=5, delay=5, backoff=1, logger=True):
+    """
+    Retry decorator with exponential backoff.
+
+    Parameters
+    ----------
+    func : typing.Callable, optional
+        Callable on which the decorator is applied, by default None
+    exception : Exception or tuple of Exceptions, optional
+        Exception(s) that invoke retry, by default Exception
+    n_tries : int, optional
+        Number of tries before giving up, by default 5
+    delay : int, optional
+        Initial delay between retries in seconds, by default 5
+    backoff : int, optional
+        Backoff multiplier e.g. value of 2 will double the delay, by default 1
+    logger : bool, optional
+        Option to log or print, by default False
+
+    Returns
+    -------
+    typing.Callable
+        Decorated callable that calls itself when exception(s) occur.
+
+    Examples
+    --------
+    >>> import random
+    >>> @retry(exception=Exception, n_tries=3)
+    ... def test_random(text):
+    ...    x = random.random()
+    ...    if x < 0.5:
+    ...        raise Exception("Fail")
+    ...    else:
+    ...        print("Success: ", text)
+    >>> test_random("It works!")
+    """
+
+    if func is None:
+        return partial(
+            retry,
+            exception=exception,
+            n_tries=n_tries,
+            delay=delay,
+            backoff=backoff,
+            logger=logger,
+        )
+
+    @wraps(func)
+    def wrapper(*args, **kwargs):
+        _n_tries, n_delay = n_tries, delay
+        log = logging.getLogger('rhodecode.retry')
+
+        while _n_tries > 1:
+            try:
+                return func(*args, **kwargs)
+            except exception as e:
+                e_details = repr(e)
+                msg = "Exception on calling func {func}: {e}, " \
+                      "Retrying in {n_delay} seconds..."\
+                    .format(func=func, e=e_details, n_delay=n_delay)
+                if logger:
+                    log.warning(msg)
+                else:
+                    print(msg)
+                time.sleep(n_delay)
+                _n_tries -= 1
+                n_delay *= backoff
+
+        return func(*args, **kwargs)
+
+    return wrapper