Fixed #23664 -- Provided a consistent definition for OrderedSet.__bool__

This also defines QuerySet.__bool__ for consistency though this should not have any consequence as bool(qs) used to fallback on QuerySet.__len__ in Py3.

django/db/models/query.py

@@ -162,10 +162,13 @@ class QuerySet(object):
         self._fetch_all()
         return iter(self._result_cache)
 
-    def __nonzero__(self):
+    def __bool__(self):
         self._fetch_all()
         return bool(self._result_cache)
 
+    def __nonzero__(self):      # Python 2 compatibility
+        return type(self).__bool__(self)
+
     def __getitem__(self, k):
         """
         Retrieves an item or slice from the set of results.

django/utils/datastructures.py

@@ -271,9 +271,12 @@ class OrderedSet(object):
     def __contains__(self, item):
         return item in self.dict
 
-    def __nonzero__(self):
+    def __bool__(self):
         return bool(self.dict)
 
+    def __nonzero__(self):      # Python 2 compatibility
+        return type(self).__bool__(self)
+
 
 class MultiValueDictKeyError(KeyError):
     pass

tests/utils_tests/test_datastructures.py

@@ -8,7 +8,7 @@ import pickle
 from django.test import SimpleTestCase
 from django.test.utils import IgnoreDeprecationWarningsMixin
 from django.utils.datastructures import (DictWrapper, ImmutableList,
-    MultiValueDict, MultiValueDictKeyError, MergeDict, SortedDict)
+    MultiValueDict, MultiValueDictKeyError, MergeDict, OrderedSet, SortedDict)
 from django.utils import six
 
 
@@ -206,6 +206,16 @@ class MergeDictTests(IgnoreDeprecationWarningsMixin, SimpleTestCase):
             d1['key2']
 
 
+class OrderedSetTests(SimpleTestCase):
+
+    def test_bool(self):
+        # Refs #23664
+        s = OrderedSet()
+        self.assertFalse(s)
+        s.add(1)
+        self.assertTrue(s)
+
+
 class MultiValueDictTests(SimpleTestCase):
 
     def test_multivaluedict(self):