Rewrite dependency tickets ordering, using Case annotation

helpdesk/apps.py

@@ -11,7 +11,3 @@ class HelpdeskConfig(AppConfig):
 
     def ready(self):
         from . import webhooks # noqa: F401
-
-        from django.db.models.fields import Field
-        from helpdesk.orm_operators import NotIn
-        Field.register_lookup(NotIn)

helpdesk/orm_operators.py

@@ -1,7 +0,0 @@
-from django.db.models.lookups import In
-
-class NotIn(In):
-    lookup_name = "not_in"
-
-    def get_rhs_op(self, connection, rhs):
-        return "NOT IN %s" % rhs

helpdesk/views/staff.py

@@ -20,7 +20,7 @@ from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import PermissionDenied
 from django.core.handlers.wsgi import WSGIRequest
 from django.core.paginator import EmptyPage, PageNotAnInteger, Paginator
-from django.db.models import Q
+from django.db.models import Q, Case, Value, When
 from django.forms import HiddenInput, inlineformset_factory, TextInput
 from django.http import Http404, HttpResponse, HttpResponseRedirect, JsonResponse
 from django.shortcuts import get_object_or_404, redirect, render
@@ -423,9 +423,12 @@ def view_ticket(request, ticket_id):
 
         return redirect('helpdesk:edit_ticket_checklist', ticket.id, checklist.id)
 
-    # Open tickets on top
-    dependencies = list(ticket.ticketdependency.filter(depends_on__status__in=Ticket.OPEN_STATUSES)) \
-        + list(ticket.ticketdependency.filter(depends_on__status__not_in=Ticket.OPEN_STATUSES))
+    # List open tickets on top
+    dependencies = ticket.ticketdependency.annotate(
+        rank=Case(
+                When(depends_on__status__in=Ticket.OPEN_STATUSES, then=Value('1')),
+                default=Value('2')
+        )).order_by('rank')
     
     return render(request, 'helpdesk/ticket.html', {
         'ticket': ticket,