Made retrieve_search_results() always return a queryset, which lets us use .exists() on the returned value as needed.

- Legacy-Id: 12007

ietf/doc/views_search.py

@@ -38,10 +38,12 @@ from django.conf import settings
 from django.core.cache import cache
 from django.core.urlresolvers import reverse as urlreverse
 from django.db.models import Q
+from django.db.models.query import EmptyQuerySet
 from django.http import Http404, HttpResponseBadRequest, HttpResponse, HttpResponseRedirect, QueryDict
 from django.shortcuts import render
 from django.utils.cache import _generate_cache_key
 
+
 import debug                            # pyflakes:ignore
 
 from ietf.doc.models import ( Document, DocHistory, DocAlias, State,
@@ -142,7 +144,7 @@ def retrieve_search_results(form, all_types=False):
         types.extend(query["doctypes"])
 
         if not types:
-            return []
+            return EmptyQuerySet()
 
         docs = Document.objects.filter(type__in=types)