Safe way to get changeset if error occur it redirects to changeset with

        proper message. If partial is set then don't do redirect raise Exception

        instead

        :param rev: revision to fetch

        :param repo: repo instance

        """

        try:

            type_, rev = rev

            return repo.scm_instance.get_changeset(rev)

        except EmptyRepositoryError, e:

            if not redirect_after:

                return None

            h.flash(h.literal(_('There are no changesets yet')),

                    category='warning')

            redirect(url('summary_home', repo_name=repo.repo_name))

        except RepositoryError, e:

            log.error(traceback.format_exc())

            h.flash(str(e), category='warning')

            if not partial:

                redirect(h.url('summary_home', repo_name=repo.repo_name))

            raise HTTPBadRequest()

    def _get_changesets(self, alias, org_repo, org_ref, other_repo, other_ref, merge):

        """

        Returns a list of changesets that can be merged from org_repo@org_ref

        to other_repo@other_ref ... and the ancestor that would be used for merge

        :param org_repo:

        :param org_ref:

        :param other_repo:

        :param other_ref:

        :param tmp:

        """

        ancestor = None

        if alias == 'hg':

            # lookup up the exact node id

            _revset_predicates = {

                    'branch': 'branch',

                    'book': 'bookmark',

                    'tag': 'tag',

                    'rev': 'id',

                }

            org_rev = org_repo._repo[org_revs[-1] if org_revs else -1].hex()

            other_rev = other_repo._repo[other_revs[-1] if other_revs else -1].hex()

            #case two independent repos

            if org_repo != other_repo:

                hgrepo = unionrepo.unionrepository(other_repo.baseui,

                                                   other_repo.path,

                                                   org_repo.path)

                # all the changesets we are looking for will be in other_repo,

                # so rev numbers from hgrepo can be used in other_repo

            #no remote compare do it on the same repository

            else:

                hgrepo = other_repo._repo

            if merge:

                if ancestors:

                    # pick arbitrary ancestor - but there is usually only one

                    ancestor = hgrepo[ancestors[0]].hex()

            else:

                # TODO: have both + and - changesets

        elif alias == 'git':

            if org_repo != other_repo:

                raise Exception('Comparing of different GIT repositories is not'

                                'allowed. Got %s != %s' % (org_repo, other_repo))

            so, se = org_repo.run_git_command(

                'log --reverse --pretty="format: %%H" -s -p %s..%s'

                    % (org_ref[1], other_ref[1])

            )

            changesets = [org_repo.get_changeset(cs)

                          for cs in re.findall(r'[0-9a-fA-F]{40}', so)]

        return changesets, ancestor

    @LoginRequired()

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

                                   'repository.admin')

    def index(self, org_ref_type, org_ref, other_ref_type, other_ref):

        # org_ref will be evaluated in org_repo

        org_repo = c.rhodecode_db_repo.repo_name

        org_ref = (org_ref_type, org_ref)

        # other_ref will be evaluated in other_repo

        other_ref = (other_ref_type, other_ref)

        other_repo = request.GET.get('other_repo', org_repo)

        # If merge is True:

        #   Show what org would get if merged with other:

        #   List changesets that are ancestors of other but not of org.

        #   New changesets in org is thus ignored.

        #   Diff will be from common ancestor, and merges of org to other will thus be ignored.

        # If merge is False:

        #   Make a raw diff from org to other, no matter if related or not.

        #   Changesets in one and not in the other will be ignored

        merge = bool(request.GET.get('merge'))

        # fulldiff disables cut_off_limit

        c.fulldiff = request.GET.get('fulldiff')

        # partial uses compare_cs.html template directly

        partial = request.environ.get('HTTP_X_PARTIAL_XHR')

        # as_form puts hidden input field with changeset revisions

        c.as_form = partial and request.GET.get('as_form')

        # swap url for compare_diff page - never partial and never as_form

        c.swap_url = h.url('compare_url',

            repo_name=other_repo,

            org_ref_type=other_ref[0], org_ref=other_ref[1],

            other_repo=org_repo,

            other_ref_type=org_ref[0], other_ref=org_ref[1],

            merge=merge or '')

import logging

import traceback

import formencode

from webob.exc import HTTPNotFound, HTTPForbidden

from collections import defaultdict

from itertools import groupby

from pylons import request, response, session, tmpl_context as c, url

from pylons.controllers.util import abort, redirect

from pylons.i18n.translation import _

from rhodecode.lib.compat import json

from rhodecode.lib.base import BaseRepoController, render

from rhodecode.lib.auth import LoginRequired, HasRepoPermissionAnyDecorator,\

    NotAnonymous

from rhodecode.lib.helpers import Page

from rhodecode.lib import helpers as h

from rhodecode.lib import diffs

from rhodecode.lib.utils import action_logger, jsonify

from rhodecode.lib.vcs.utils import safe_str

from rhodecode.lib.vcs.exceptions import EmptyRepositoryError

from rhodecode.lib.vcs.backends.base import EmptyChangeset

from rhodecode.lib.diffs import LimitedDiffContainer

from rhodecode.model.db import User, PullRequest, ChangesetStatus,\

    ChangesetComment

from rhodecode.model.pull_request import PullRequestModel

from rhodecode.model.meta import Session

from rhodecode.model.repo import RepoModel

from rhodecode.model.comment import ChangesetCommentsModel

from rhodecode.model.changeset_status import ChangesetStatusModel

from rhodecode.model.forms import PullRequestForm

from mercurial import scmutil

from rhodecode.lib.utils2 import safe_int

log = logging.getLogger(__name__)

class PullrequestsController(BaseRepoController):

    def __before__(self):

        super(PullrequestsController, self).__before__()

        repo_model = RepoModel()

        c.users_array = repo_model.get_users_js()

        c.users_groups_array = repo_model.get_users_groups_js()

    def _get_repo_refs(self, repo, rev=None, branch_rev=None):

        """return a structure with repo's interesting changesets, suitable for

        # list named branches that has been merged to this named branch - it should probably merge back

        peers = []

        if rev:

            rev = safe_str(rev)

        if branch_rev:

            branch_rev = safe_str(branch_rev)

            # not restricting to merge() would also get branch point and be better

            # (especially because it would get the branch point) ... but is currently too expensive

            otherbranches = {}

                cs = repo.get_changeset(i)

                otherbranches[cs.branch] = cs.raw_id

        selected = None

        branches = []

            if rev == branchrev:

                selected = n

        bookmarks = []

        for bookmark, bookmarkrev in repo.bookmarks.iteritems():

            n = 'book:%s:%s' % (bookmark, bookmarkrev)

            bookmarks.append((n, bookmark))

            if rev == bookmarkrev:

                selected = n

        tags = []

        for tag, tagrev in repo.tags.iteritems():

            n = 'tag:%s:%s' % (tag, tagrev)

            tags.append((n, tag))

            if rev == tagrev and tag != 'tip': # tip is not a real tag - and its branch is better

                selected = n

        # prio 1: rev was selected as existing entry above

        # prio 2: create special entry for rev; rev _must_ be used

        specials = []

        if rev and selected is None:

            selected = 'rev:%s:%s' % (rev, rev)

            specials = [(selected, '%s: %s' % (_("Changeset"), rev[:12]))]

        # prio 3: most recent peer branch

        if peers and not selected:

            selected = peers[0][0][0]

        # prio 4: tip revision

        if not selected:

            selected = 'tag:tip:%s' % repo.tags['tip']

        groups = [(specials, _("Special")),

                  (peers, _("Peer branches")),

                  (bookmarks, _("Bookmarks")),

                  (branches, _("Branches")),

                  (tags, _("Tags")),

                  ]

        return [g for g in groups if g[0]], selected

    def _get_is_allowed_change_status(self, pull_request):

        owner = self.rhodecode_user.user_id == pull_request.user_id

        reviewer = self.rhodecode_user.user_id in [x.user_id for x in

                                                   pull_request.reviewers]

        return (self.rhodecode_user.admin or owner or reviewer)

    def _load_compare_data(self, pull_request, enable_comments=True):

        """

        Load context data needed for generating compare diff

        :param pull_request:

        :type pull_request:

        """

        org_repo = pull_request.org_repo

        (org_ref_type,

         org_ref_name,

         org_ref_rev) = pull_request.org_ref.split(':')