This file was forked by the Kallithea project in July 2014.

Original author and date, and relevant copyright and licensing information is below:

:created_on: May 7, 2012

:author: marcink

:copyright: (c) 2013 RhodeCode GmbH, and others.

:license: GPLv3, see LICENSE.md for more details.

"""

import logging

import traceback

import formencode

import re

from pylons import request, tmpl_context as c

from pylons.i18n.translation import _

from webob.exc import HTTPFound, HTTPNotFound, HTTPForbidden, HTTPBadRequest

from kallithea.config.routing import url

from kallithea.lib import helpers as h

from kallithea.lib import diffs

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

    NotAnonymous

from kallithea.lib.base import BaseRepoController, render

from kallithea.lib.compat import json, OrderedDict

from kallithea.lib.diffs import LimitedDiffContainer

from kallithea.lib.exceptions import UserInvalidException

from kallithea.lib.page import Page

from kallithea.lib.utils import action_logger, jsonify

from kallithea.lib.vcs.exceptions import EmptyRepositoryError, ChangesetDoesNotExistError

from kallithea.lib.vcs.utils import safe_str

from kallithea.lib.vcs.utils.hgcompat import unionrepo

from kallithea.model.db import PullRequest, ChangesetStatus, ChangesetComment, \

    PullRequestReviewer, User

from kallithea.model.pull_request import PullRequestModel

from kallithea.model.meta import Session

from kallithea.model.repo import RepoModel

from kallithea.model.comment import ChangesetCommentsModel

from kallithea.model.changeset_status import ChangesetStatusModel

from kallithea.model.forms import PullRequestForm, PullRequestPostForm

from kallithea.lib.utils2 import safe_int

from kallithea.controllers.changeset import _ignorews_url, _context_url, \

    create_comment

from kallithea.controllers.compare import CompareController

from kallithea.lib.graphmod import graph_data

log = logging.getLogger(__name__)

class PullrequestsController(BaseRepoController):

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

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

        the selectors in pullrequest.html

        rev: a revision that must be in the list somehow and selected by default

        branch: a branch that must be in the list and selected by default - even if closed

        branch_rev: a revision of which peers should be preferred and available."""

        # 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:

            branch = safe_str(branch)

        if branch_rev:

            branch_rev = safe_str(branch_rev)

            # a revset not restricting to merge() would be better

            # (especially because it would get the branch point)

            # ... but is currently too expensive

            # including branches of children could be nice too

            peerbranches = set()

            for i in repo._repo.revs(

                "sort(parents(branch(id(%s)) and merge()) - branch(id(%s)), -rev)",

                branch_rev, branch_rev):

                abranch = repo.get_changeset(i).branch

                if abranch not in peerbranches:

                    n = 'branch:%s:%s' % (abranch, repo.get_changeset(abranch).raw_id)

                    peers.append((n, abranch))

                    peerbranches.add(abranch)

        selected = None

        tiprev = repo.tags.get('tip')

        tipbranch = None

        branches = []

        for abranch, branchrev in repo.branches.iteritems():

            n = 'branch:%s:%s' % (abranch, branchrev)

            desc = abranch

            if branchrev == tiprev:

                tipbranch = abranch

                desc = '%s (current tip)' % desc

            branches.append((n, desc))

            if rev == branchrev:

                selected = n

            if branch == abranch:

                if not rev:

                    selected = n

                branch = None

        if branch:  # branch not in list - it is probably closed

            branchrev = repo.closed_branches.get(branch)

            if branchrev:

                n = 'branch:%s:%s' % (branch, branchrev)

                branches.append((n, _('%s (closed)') % branch))

                selected = n

                branch = None

            if branch:

                log.debug('branch %r not found in %s', branch, repo)

        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():

            if tag == 'tip':

                continue

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

            tags.append((n, tag))

            # note: even if rev == tagrev, don't select the static tag - it must be chosen explicitly

        # 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]

        # prio 4: tip revision

        if not selected:

            if h.is_hg(repo):

                if tipbranch:

                    selected = 'branch:%s:%s' % (tipbranch, tiprev)

                else:

                    selected = 'tag:null:' + repo.EMPTY_CHANGESET

                    tags.append((selected, 'null'))

            else:

                if 'master' in repo.branches:

                    selected = 'branch:master:%s' % repo.branches['master']

                else:

                    k, v = repo.branches.items()[0]

                    selected = 'branch:%s:%s' % (k, v)

        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):

        if pull_request.is_closed():

            return False

        owner = self.authuser.user_id == pull_request.owner_id

        reviewer = PullRequestReviewer.query() \

            .filter(PullRequestReviewer.pull_request == pull_request) \

            .filter(PullRequestReviewer.user_id == self.authuser.user_id) \

            .count() != 0

        return self.authuser.admin or owner or reviewer

    @LoginRequired()

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

                                   'repository.admin')

    def show_all(self, repo_name):

        c.from_ = request.GET.get('from_') or ''

        c.closed = request.GET.get('closed') or ''

        p = safe_int(request.GET.get('page'), 1)

        q = PullRequest.query(include_closed=c.closed, sorted=True)

        if c.from_:

            q = q.filter_by(org_repo=c.db_repo)

        else:

            q = q.filter_by(other_repo=c.db_repo)

        c.pull_requests = q.all()

        c.pullrequests_pager = Page(c.pull_requests, page=p, items_per_page=100)

        return render('/pullrequests/pullrequest_show_all.html')

    @LoginRequired()

    @NotAnonymous()

    def show_my(self):

        c.closed = request.GET.get('closed') or ''

        c.my_pull_requests = PullRequest.query(

            include_closed=c.closed,

            sorted=True,

        ).filter_by(owner_id=self.authuser.user_id).all()

        c.participate_in_pull_requests = []

        c.participate_in_pull_requests_todo = []

        done_status = set([ChangesetStatus.STATUS_APPROVED, ChangesetStatus.STATUS_REJECTED])

        for pr in PullRequest.query(

            include_closed=c.closed,

            reviewer_id=self.authuser.user_id,

            sorted=True,

        ):

            status = pr.user_review_status(c.authuser.user_id) # very inefficient!!!

            if status in done_status:

                c.participate_in_pull_requests.append(pr)

            else:

                c.participate_in_pull_requests_todo.append(pr)

        return render('/pullrequests/pullrequest_show_my.html')

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    def index(self):

        org_repo = c.db_repo

        org_scm_instance = org_repo.scm_instance

        try:

            org_scm_instance.get_changeset()

        except EmptyRepositoryError as e:

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

                    category='warning')

            raise HTTPFound(location=url('summary_home', repo_name=org_repo.repo_name))

        org_rev = request.GET.get('rev_end')

        # rev_start is not directly useful - its parent could however be used

        # as default for other and thus give a simple compare view

        rev_start = request.GET.get('rev_start')

        other_rev = None

        if rev_start:

            starters = org_repo.get_changeset(rev_start).parents

            if starters:

                other_rev = starters[0].raw_id

            else:

                other_rev = org_repo.scm_instance.EMPTY_CHANGESET

        branch = request.GET.get('branch')

        c.cs_repos = [(org_repo.repo_name, org_repo.repo_name)]

        c.default_cs_repo = org_repo.repo_name

        c.cs_refs, c.default_cs_ref = self._get_repo_refs(org_scm_instance, rev=org_rev, branch=branch)

        default_cs_ref_type, default_cs_branch, default_cs_rev = c.default_cs_ref.split(':')

        if default_cs_ref_type != 'branch':

            default_cs_branch = org_repo.get_changeset(default_cs_rev).branch

        # add org repo to other so we can open pull request against peer branches on itself

        c.a_repos = [(org_repo.repo_name, '%s (self)' % org_repo.repo_name)]

        if org_repo.parent:

            # add parent of this fork also and select it.

            # use the same branch on destination as on source, if available.

            c.a_repos.append((org_repo.parent.repo_name, '%s (parent)' % org_repo.parent.repo_name))

            c.a_repo = org_repo.parent

            c.a_refs, c.default_a_ref = self._get_repo_refs(

                    org_repo.parent.scm_instance, branch=default_cs_branch, rev=other_rev)

        else:

            c.a_repo = org_repo

            c.a_refs, c.default_a_ref = self._get_repo_refs(org_scm_instance, rev=other_rev)

        # gather forks and add to this list ... even though it is rare to

        # request forks to pull from their parent

        for fork in org_repo.forks:

            c.a_repos.append((fork.repo_name, fork.repo_name))

        return render('/pullrequests/pullrequest.html')

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    @jsonify

    def repo_info(self, repo_name):

        repo = c.db_repo

        refs, selected_ref = self._get_repo_refs(repo.scm_instance)

        return {

            'description': repo.description.split('\n', 1)[0],

            'selected_ref': selected_ref,

            'refs': refs,

            }

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    def create(self, repo_name):

        repo = c.db_repo

        try:

            _form = PullRequestForm(repo.repo_id)().to_python(request.POST)

        except formencode.Invalid as errors:

            log.error(traceback.format_exc())

            log.error(str(errors))

            msg = _('Error creating pull request: %s') % errors.msg

            h.flash(msg, 'error')

            raise HTTPBadRequest

        # heads up: org and other might seem backward here ...

        org_repo_name = _form['org_repo']

        org_ref = _form['org_ref'] # will have merge_rev as rev but symbolic name

        org_repo = RepoModel()._get_repo(org_repo_name)

        (org_ref_type,

         org_ref_name,

         org_rev) = org_ref.split(':')

        if org_ref_type == 'rev':

            org_ref_type = 'branch'

            cs = org_repo.scm_instance.get_changeset(org_rev)

            org_ref = '%s:%s:%s' % (org_ref_type, cs.branch, cs.raw_id)

        other_repo_name = _form['other_repo']

        other_ref = _form['other_ref'] # will have symbolic name and head revision

        other_repo = RepoModel()._get_repo(other_repo_name)

        (other_ref_type,

         other_ref_name,

         other_rev) = other_ref.split(':')

        if other_ref_type == 'rev':

            cs = other_repo.scm_instance.get_changeset(other_rev)

            other_ref_name = cs.raw_id[:12]

            other_ref = '%s:%s:%s' % (other_ref_type, other_ref_name, cs.raw_id)

        cs_ranges, _cs_ranges_not, ancestor_revs = \

            CompareController._get_changesets(org_repo.scm_instance.alias,

                                              other_repo.scm_instance, other_rev, # org and other "swapped"

                                              org_repo.scm_instance, org_rev,

                                              )

        ancestor_rev = msg = None

        if not cs_ranges:

            msg = _('Cannot create empty pull request')

        elif not ancestor_revs:

            ancestor_rev = org_repo.scm_instance.EMPTY_CHANGESET

        elif len(ancestor_revs) == 1:

            ancestor_rev = ancestor_revs[0]

        else:

            msg = _('Cannot create pull request - criss cross merge detected, please merge a later %s revision to %s'

                    ) % (other_ref_name, org_ref_name)

        if ancestor_rev is None:

            h.flash(msg, category='error')

            log.error(msg)

            raise HTTPNotFound

        revisions = [cs_.raw_id for cs_ in cs_ranges]

        # hack: ancestor_rev is not an other_rev but we want to show the

        # requested destination and have the exact ancestor

        other_ref = '%s:%s:%s' % (other_ref_type, other_ref_name, ancestor_rev)

        reviewer_ids = []

        title = _form['pullrequest_title']

        if not title:

            if org_repo_name == other_repo_name:

                title = '%s to %s' % (h.short_ref(org_ref_type, org_ref_name),

                                      h.short_ref(other_ref_type, other_ref_name))

            else:

                title = '%s#%s to %s#%s' % (org_repo_name, h.short_ref(org_ref_type, org_ref_name),

                                            other_repo_name, h.short_ref(other_ref_type, other_ref_name))

        description = _form['pullrequest_desc'].strip() or _('No description')

        try:

            pull_request = PullRequestModel().create(

                self.authuser.user_id, org_repo_name, org_ref, other_repo_name,

                other_ref, revisions, reviewer_ids, title, description

            )

            Session().commit()

            h.flash(_('Successfully opened new pull request'),

                    category='success')

        except UserInvalidException as u:

            h.flash(_('Invalid reviewer "%s" specified') % u, category='error')

            raise HTTPBadRequest()

        except Exception:

            h.flash(_('Error occurred while creating pull request'),

                    category='error')

            log.error(traceback.format_exc())

            raise HTTPFound(location=url('pullrequest_home', repo_name=repo_name))

        raise HTTPFound(location=pull_request.url())

    def create_new_iteration(self, old_pull_request, new_rev, title, description, reviewer_ids):

        org_ref_type, org_ref_name, org_rev = old_pull_request.org_ref.split(':')

        new_org_rev = self._get_ref_rev(org_repo, 'rev', new_rev)

        other_ref_type, other_ref_name, other_rev = old_pull_request.other_ref.split(':') # other_rev is ancestor

        #assert other_ref_type == 'branch', other_ref_type # TODO: what if not?

        new_other_rev = self._get_ref_rev(other_repo, other_ref_type, other_ref_name)

        cs_ranges, _cs_ranges_not, ancestor_revs = CompareController._get_changesets(org_repo.scm_instance.alias,

            other_repo.scm_instance, new_other_rev, # org and other "swapped"

            org_repo.scm_instance, new_org_rev)

        ancestor_rev = msg = None

        if not cs_ranges:

            msg = _('Cannot create empty pull request update') # cannot happen!

        elif not ancestor_revs:

            msg = _('Cannot create pull request update - no common ancestor found') # cannot happen

        elif len(ancestor_revs) == 1:

            ancestor_rev = ancestor_revs[0]

        else:

            msg = _('Cannot create pull request update - criss cross merge detected, please merge a later %s revision to %s'

                    ) % (other_ref_name, org_ref_name)

        if ancestor_rev is None:

            h.flash(msg, category='error')

            log.error(msg)

            raise HTTPNotFound

        old_revisions = set(old_pull_request.revisions)

        revisions = [cs.raw_id for cs in cs_ranges]

        new_revisions = [r for r in revisions if r not in old_revisions]

        lost = old_revisions.difference(revisions)

        infos = ['This is a new iteration of %s "%s".' %

                 (h.canonical_url('pullrequest_show', repo_name=old_pull_request.other_repo.repo_name,

                      pull_request_id=old_pull_request.pull_request_id),

                  old_pull_request.title)]

        if lost:

            infos.append(_('Missing changesets since the previous iteration:'))

            for r in old_pull_request.revisions:

                if r in lost:

                    rev_desc = org_repo.get_changeset(r).message.split('\n')[0]

                    infos.append('  %s %s' % (h.short_id(r), rev_desc))

        if new_revisions:

            infos.append(_('New changesets on %s %s since the previous iteration:') % (org_ref_type, org_ref_name))

            for r in reversed(revisions):

                if r in new_revisions:

                    rev_desc = org_repo.get_changeset(r).message.split('\n')[0]

                    infos.append('  %s %s' % (h.short_id(r), h.shorter(rev_desc, 80)))

            if ancestor_rev == other_rev:

                infos.append(_("Ancestor didn't change - diff since previous iteration:"))

                infos.append(h.canonical_url('compare_url',

                                 repo_name=org_repo.repo_name, # other_repo is always same as repo_name

                                 org_ref_type='rev', org_ref_name=h.short_id(org_rev), # use old org_rev as base

                                 other_ref_type='rev', other_ref_name=h.short_id(new_org_rev),

                                 )) # note: linear diff, merge or not doesn't matter

            else:

                infos.append(_('This iteration is based on another %s revision and there is no simple diff.') % other_ref_name)

        else:

           infos.append(_('No changes found on %s %s since previous iteration.') % (org_ref_type, org_ref_name))

           # TODO: fail?

        # hack: ancestor_rev is not an other_ref but we want to show the

        # requested destination and have the exact ancestor

        new_other_ref = '%s:%s:%s' % (other_ref_type, other_ref_name, ancestor_rev)

        new_org_ref = '%s:%s:%s' % (org_ref_type, org_ref_name, new_org_rev)

        try:

            title, old_v = re.match(r'(.*)\(v(\d+)\)\s*$', title).groups()

            v = int(old_v) + 1

        except (AttributeError, ValueError):

            v = 2

        title = '%s (v%s)' % (title.strip(), v)

        # using a mail-like separator, insert new iteration info in description with latest first

        descriptions = description.replace('\r\n', '\n').split('\n-- \n', 1)

        description = descriptions[0].strip() + '\n\n-- \n' + '\n'.join(infos)

        if len(descriptions) > 1:

            description += '\n\n' + descriptions[1].strip()

        try:

            pull_request = PullRequestModel().create(

                self.authuser.user_id,

                old_pull_request.org_repo.repo_name, new_org_ref,

                old_pull_request.other_repo.repo_name, new_other_ref,

                revisions, reviewer_ids, title, description

            )

        except UserInvalidException as u:

            h.flash(_('Invalid reviewer "%s" specified') % u, category='error')

            raise HTTPBadRequest()

        except Exception:

            h.flash(_('Error occurred while creating pull request'),

                    category='error')

            log.error(traceback.format_exc())

            raise HTTPFound(location=old_pull_request.url())

        ChangesetCommentsModel().create(

            text=_('Closed, next iteration: %s .') % pull_request.url(canonical=True),

            repo=old_pull_request.other_repo_id,

            author=c.authuser.user_id,

            pull_request=old_pull_request.pull_request_id,

            closing_pr=True)

        PullRequestModel().close_pull_request(old_pull_request.pull_request_id)

        Session().commit()

        h.flash(_('New pull request iteration created'),

                category='success')

        raise HTTPFound(location=pull_request.url())

    # pullrequest_post for PR editing

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    def post(self, repo_name, pull_request_id):

        pull_request = PullRequest.get_or_404(pull_request_id)

        if pull_request.is_closed():

            raise HTTPForbidden()

        assert pull_request.other_repo.repo_name == repo_name

        #only owner or admin can update it

        owner = pull_request.owner_id == c.authuser.user_id

        repo_admin = h.HasRepoPermissionAny('repository.admin')(c.repo_name)

        if not (h.HasPermissionAny('hg.admin')() or repo_admin or owner):

            raise HTTPForbidden()

        _form = PullRequestPostForm()().to_python(request.POST)

        reviewer_ids = set(int(s) for s in _form['review_members'])

        org_reviewer_ids = set(int(s) for s in _form['org_review_members'])

        current_reviewer_ids = set(prr.user_id for prr in pull_request.reviewers)

        other_added = [User.get(u) for u in current_reviewer_ids - org_reviewer_ids]

        other_removed = [User.get(u) for u in org_reviewer_ids - current_reviewer_ids]

        if other_added:

            h.flash(_('Meanwhile, the following reviewers have been added: %s') %

                    (', '.join(u.username for u in other_added)),

                    category='warning')

        if other_removed:

            h.flash(_('Meanwhile, the following reviewers have been removed: %s') %

                    (', '.join(u.username for u in other_removed)),

                    category='warning')

        if _form['updaterev']:

            return self.create_new_iteration(pull_request,

                                      _form['updaterev'],

                                      _form['pullrequest_title'],

                                      _form['pullrequest_desc'],

                                      reviewer_ids)

        old_description = pull_request.description

        pull_request.title = _form['pullrequest_title']

        pull_request.description = _form['pullrequest_desc'].strip() or _('No description')

        pull_request.owner = User.get_by_username(_form['owner'])

        user = User.get(c.authuser.user_id)

        add_reviewer_ids = reviewer_ids - org_reviewer_ids - current_reviewer_ids

        remove_reviewer_ids = (org_reviewer_ids - reviewer_ids) & current_reviewer_ids

        try:

            PullRequestModel().mention_from_description(user, pull_request, old_description)

            PullRequestModel().add_reviewers(user, pull_request, add_reviewer_ids)

            PullRequestModel().remove_reviewers(user, pull_request, remove_reviewer_ids)

        except UserInvalidException as u:

            h.flash(_('Invalid reviewer "%s" specified') % u, category='error')

            raise HTTPBadRequest()

        Session().commit()

        h.flash(_('Pull request updated'), category='success')

        raise HTTPFound(location=pull_request.url())

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    @jsonify

    def delete(self, repo_name, pull_request_id):

        pull_request = PullRequest.get_or_404(pull_request_id)

        #only owner can delete it !

        if pull_request.owner_id == c.authuser.user_id:

            PullRequestModel().delete(pull_request)

            Session().commit()

            h.flash(_('Successfully deleted pull request'),

                    category='success')

            raise HTTPFound(location=url('my_pullrequests'))

        raise HTTPForbidden()

    @LoginRequired()

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

                                   'repository.admin')

    def show(self, repo_name, pull_request_id, extra=None):

        repo_model = RepoModel()

        c.users_array = repo_model.get_users_js()

        c.user_groups_array = repo_model.get_user_groups_js()

        c.pull_request = PullRequest.get_or_404(pull_request_id)

        c.allowed_to_change_status = self._get_is_allowed_change_status(c.pull_request)

        cc_model = ChangesetCommentsModel()

        cs_model = ChangesetStatusModel()

        # pull_requests repo_name we opened it against

        # ie. other_repo must match

        if repo_name != c.pull_request.other_repo.repo_name:

            raise HTTPNotFound

        # load compare data into template context

        c.cs_repo = c.pull_request.org_repo

        (c.cs_ref_type,

         c.cs_ref_name,

         c.cs_rev) = c.pull_request.org_ref.split(':')

        c.a_repo = c.pull_request.other_repo

        (c.a_ref_type,

         c.a_ref_name,

         c.a_rev) = c.pull_request.other_ref.split(':') # a_rev is ancestor

        org_scm_instance = c.cs_repo.scm_instance # property with expensive cache invalidation check!!!

        c.cs_repo = c.cs_repo

        try:

            c.cs_ranges = [org_scm_instance.get_changeset(x)

                           for x in c.pull_request.revisions]

        except ChangesetDoesNotExistError:

            c.cs_ranges = []

            h.flash(_('Revision %s not found in %s') % (x, c.cs_repo.repo_name),

                'error')

        c.cs_ranges_org = None # not stored and not important and moving target - could be calculated ...

        revs = [ctx.revision for ctx in reversed(c.cs_ranges)]

        c.jsdata = json.dumps(graph_data(org_scm_instance, revs))

        c.is_range = False

        try:

            if c.a_ref_type == 'rev': # this looks like a free range where target is ancestor

                cs_a = org_scm_instance.get_changeset(c.a_rev)

                root_parents = c.cs_ranges[0].parents

                c.is_range = cs_a in root_parents

                #c.merge_root = len(root_parents) > 1 # a range starting with a merge might deserve a warning

        except ChangesetDoesNotExistError: # probably because c.a_rev not found

            pass

        except IndexError: # probably because c.cs_ranges is empty, probably because revisions are missing

            pass

        avail_revs = set()

        avail_show = []

        c.cs_branch_name = c.cs_ref_name

        c.a_branch_name = None

        other_scm_instance = c.a_repo.scm_instance

        c.update_msg = ""

        c.update_msg_other = ""

        try:

            if not c.cs_ranges:

                c.update_msg = _('Error: changesets not found when displaying pull request from %s.') % c.cs_rev

            elif org_scm_instance.alias == 'hg' and c.a_ref_name != 'ancestor':

                if c.cs_ref_type != 'branch':

                    c.cs_branch_name = org_scm_instance.get_changeset(c.cs_ref_name).branch # use ref_type ?

                c.a_branch_name = c.a_ref_name

                if c.a_ref_type != 'branch':

                    try:

                        c.a_branch_name = other_scm_instance.get_changeset(c.a_ref_name).branch # use ref_type ?

                    except EmptyRepositoryError:

                        c.a_branch_name = 'null' # not a branch name ... but close enough

                # candidates: descendants of old head that are on the right branch

                #             and not are the old head itself ...

                #             and nothing at all if old head is a descendant of target ref name

                if not c.is_range and other_scm_instance._repo.revs('present(%s)::&%s', c.cs_ranges[-1].raw_id, c.a_branch_name):

                    c.update_msg = _('This pull request has already been merged to %s.') % c.a_branch_name

                elif c.pull_request.is_closed():

                    c.update_msg = _('This pull request has been closed and can not be updated.')

                else: # look for descendants of PR head on source branch in org repo

                    avail_revs = org_scm_instance._repo.revs('%s:: & branch(%s)',

                                                             revs[0], c.cs_branch_name)

                    if len(avail_revs) > 1: # more than just revs[0]

                        # also show changesets that not are descendants but would be merged in

                        targethead = other_scm_instance.get_changeset(c.a_branch_name).raw_id

                        if org_scm_instance.path != other_scm_instance.path:

                            # Note: org_scm_instance.path must come first so all

                            # valid revision numbers are 100% org_scm compatible

                            # - both for avail_revs and for revset results

                            hgrepo = unionrepo.unionrepository(org_scm_instance.baseui,

                                                               org_scm_instance.path,

                                                               other_scm_instance.path)

                        else:

                            hgrepo = org_scm_instance._repo

                        show = set(hgrepo.revs('::%ld & !::parents(%s) & !::%s',

                                               avail_revs, revs[0], targethead))

                        c.update_msg = _('The following additional changes are available on %s:') % c.cs_branch_name

                    else:

                        show = set()

                        avail_revs = set() # drop revs[0]

                        c.update_msg = _('No additional changesets found for iterating on this pull request.')

                    # TODO: handle branch heads that not are tip-most

                    brevs = org_scm_instance._repo.revs('%s - %ld - %s', c.cs_branch_name, avail_revs, revs[0])

                    if brevs:

                        # also show changesets that are on branch but neither ancestors nor descendants

                        show.update(org_scm_instance._repo.revs('::%ld - ::%ld - ::%s', brevs, avail_revs, c.a_branch_name))

                        show.add(revs[0]) # make sure graph shows this so we can see how they relate

                        c.update_msg_other = _('Note: Branch %s has another head: %s.') % (c.cs_branch_name,

                            h.short_id(org_scm_instance.get_changeset((max(brevs))).raw_id))

                    avail_show = sorted(show, reverse=True)

            elif org_scm_instance.alias == 'git':

                c.cs_repo.scm_instance.get_changeset(c.cs_rev) # check it exists - raise ChangesetDoesNotExistError if not

                c.update_msg = _("Git pull requests don't support iterating yet.")

        except ChangesetDoesNotExistError:

            c.update_msg = _('Error: some changesets not found when displaying pull request from %s.') % c.cs_rev

        c.avail_revs = avail_revs

        c.avail_cs = [org_scm_instance.get_changeset(r) for r in avail_show]

        c.avail_jsdata = json.dumps(graph_data(org_scm_instance, avail_show))

        raw_ids = [x.raw_id for x in c.cs_ranges]

        c.cs_comments = c.cs_repo.get_comments(raw_ids)

        c.statuses = c.cs_repo.statuses(raw_ids)

        ignore_whitespace = request.GET.get('ignorews') == '1'

        line_context = safe_int(request.GET.get('context'), 3)

        c.ignorews_url = _ignorews_url

        c.context_url = _context_url

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

        diff_limit = self.cut_off_limit if not c.fulldiff else None

        # we swap org/other ref since we run a simple diff on one repo

        log.debug('running diff between %s and %s in %s',

                  c.a_rev, c.cs_rev, org_scm_instance.path)

        try:

            txtdiff = org_scm_instance.get_diff(rev1=safe_str(c.a_rev), rev2=safe_str(c.cs_rev),

                                                ignore_whitespace=ignore_whitespace,

                                                context=line_context)

        except ChangesetDoesNotExistError:

            txtdiff =  _("The diff can't be shown - the PR revisions could not be found.")

        diff_processor = diffs.DiffProcessor(txtdiff or '', format='gitdiff',

                                             diff_limit=diff_limit)

        _parsed = diff_processor.prepare()

        c.limited_diff = False

        if isinstance(_parsed, LimitedDiffContainer):

            c.limited_diff = True

        c.file_diff_data = []

        c.lines_added = 0

        c.lines_deleted = 0

        for f in _parsed:

            st = f['stats']

            c.lines_added += st['added']

            c.lines_deleted += st['deleted']

            filename = f['filename']

            fid = h.FID('', filename)

            diff = diff_processor.as_html(enable_comments=True,

                                          parsed_lines=[f])

            c.file_diff_data.append((fid, None, f['operation'], f['old_filename'], filename, diff, st))

        # inline comments

        c.inline_cnt = 0

        c.inline_comments = cc_model.get_inline_comments(

                                c.db_repo.repo_id,

                                pull_request=pull_request_id)

        # count inline comments

        for __, lines in c.inline_comments:

            for comments in lines.values():

                c.inline_cnt += len(comments)

        # comments

        c.comments = cc_model.get_comments(c.db_repo.repo_id,

                                           pull_request=pull_request_id)

        # (badly named) pull-request status calculation based on reviewer votes

        (c.pull_request_reviewers,

         c.pull_request_pending_reviewers,

         c.current_voting_result,

         ) = cs_model.calculate_pull_request_result(c.pull_request)

        c.changeset_statuses = ChangesetStatus.STATUSES

        c.as_form = False

        c.ancestors = None # [c.a_rev] ... but that is shown in an other way

        return render('/pullrequests/pullrequest_show.html')

    @LoginRequired()

    @NotAnonymous()

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

                                   'repository.admin')

    @jsonify

    def comment(self, repo_name, pull_request_id):

        pull_request = PullRequest.get_or_404(pull_request_id)

        status = request.POST.get('changeset_status')

        close_pr = request.POST.get('save_close')

        delete = request.POST.get('save_delete')

        f_path = request.POST.get('f_path')

        line_no = request.POST.get('line')