Test cases and fix for plain-list relationships (ie not queryset) Closes #878.

rest_framework/relations.py

@@ -12,7 +12,7 @@ from django.db.models.fields import BLANK_CHOICE_DASH
 from django.forms import widgets
 from django.forms.models import ModelChoiceIterator
 from django.utils.translation import ugettext_lazy as _
-from rest_framework.fields import Field, WritableField, get_component
+from rest_framework.fields import Field, WritableField, get_component, is_simple_callable
 from rest_framework.reverse import reverse
 from rest_framework.compat import urlparse
 from rest_framework.compat import smart_text
@@ -144,7 +144,12 @@ class RelatedField(WritableField):
             return None
 
         if self.many:
-            return [self.to_native(item) for item in value.all()]
+            if is_simple_callable(getattr(value, 'all', None)):
+                return [self.to_native(item) for item in value.all()]
+            else:
+                # Also support non-queryset iterables.
+                # This allows us to also support plain lists of related items.
+                return [self.to_native(item) for item in value]
         return self.to_native(value)
 
     def field_from_native(self, data, files, field_name, into):
@@ -242,7 +247,12 @@ class PrimaryKeyRelatedField(RelatedField):
                     queryset = get_component(queryset, component)
 
             # Forward relationship
-            return [self.to_native(item.pk) for item in queryset.all()]
+            if is_simple_callable(getattr(queryset, 'all', None)):
+                return [self.to_native(item.pk) for item in queryset.all()]
+            else:
+                # Also support non-queryset iterables.
+                # This allows us to also support plain lists of related items.
+                return [self.to_native(item.pk) for item in queryset]
 
         # To-one relationship
         try:

rest_framework/tests/test_serializer.py

@@ -1558,6 +1558,8 @@ class MetadataSerializerTestCase(TestCase):
         self.assertEqual(expected, metadata)
 
 
+### Regression test for #840
+
 class SimpleModel(models.Model):
     text = models.CharField(max_length=100)
 
@@ -1573,6 +1575,7 @@ class SimpleModelSerializer(serializers.ModelSerializer):
         del attrs['other']
         return attrs
 
+
 class FieldValidationRemovingAttr(TestCase):
     def test_removing_non_model_field_in_validation(self):
         """
@@ -1587,3 +1590,44 @@ class FieldValidationRemovingAttr(TestCase):
         self.assertTrue(serializer.is_valid())
         serializer.save()
         self.assertEqual(serializer.object.text, 'foo')
+
+
+### Regression test for #878
+
+class SimpleTargetModel(models.Model):
+    text = models.CharField(max_length=100)
+
+
+class SimplePKSourceModelSerializer(serializers.Serializer):
+    targets = serializers.PrimaryKeyRelatedField(queryset=SimpleTargetModel.objects.all(), many=True)
+    text = serializers.CharField()
+
+
+class SimpleSlugSourceModelSerializer(serializers.Serializer):
+    targets = serializers.SlugRelatedField(queryset=SimpleTargetModel.objects.all(), many=True, slug_field='pk')
+    text = serializers.CharField()
+
+
+class SerializerSupportsManyRelationships(TestCase):
+    def setUp(self):
+        SimpleTargetModel.objects.create(text='foo')
+        SimpleTargetModel.objects.create(text='bar')
+
+    def test_serializer_supports_pk_many_relationships(self):
+        """
+        Regression test for #878.
+
+        Note that pk behavior has a different code path to usual cases,
+        for performance reasons.
+        """
+        serializer = SimplePKSourceModelSerializer(data={'text': 'foo', 'targets': [1, 2]})
+        self.assertTrue(serializer.is_valid())
+        self.assertEqual(serializer.data, {'text': 'foo', 'targets': [1, 2]})
+
+    def test_serializer_supports_slug_many_relationships(self):
+        """
+        Regression test for #878.
+        """
+        serializer = SimpleSlugSourceModelSerializer(data={'text': 'foo', 'targets': [1, 2]})
+        self.assertTrue(serializer.is_valid())
+        self.assertEqual(serializer.data, {'text': 'foo', 'targets': [1, 2]})