when source='*' on a nested serializer, expand fields into outer serializer when writing. fixes #765

rest_framework/serializers.py

@@ -378,6 +378,10 @@ class BaseSerializer(WritableField):
         # Set the serializer object if it exists
         obj = getattr(self.parent.object, field_name) if self.parent.object else None
 
+        if self.source == '*':
+            if value:
+                into.update(value)
+        else:
             if value in (None, ''):
                 into[(self.source or field_name)] = None
             else:

rest_framework/tests/serializer.py

@@ -78,6 +78,17 @@ class PersonSerializer(serializers.ModelSerializer):
         read_only_fields = ('age',)
 
 
+class NestedSerializer(serializers.Serializer):
+    info = serializers.Field()
+
+
+class ModelSerializerWithNestedSerializer(serializers.ModelSerializer):
+    nested = NestedSerializer(source='*')
+
+    class Meta:
+        model = Person
+
+
 class PersonSerializerInvalidReadOnly(serializers.ModelSerializer):
     """
     Testing for #652.
@@ -369,6 +380,17 @@ class ValidationTests(TestCase):
         except:
             self.fail('Wrong exception type thrown.')
 
+    def test_writable_star_source_on_nested_serializer(self):
+        """
+        Assert that a nested serializer instantiated with source='*' correctly
+        expands the data into the outer serializer.
+        """
+        serializer = ModelSerializerWithNestedSerializer(data={
+            'name': 'marko',
+            'nested': {'info': 'hi'}},
+        )
+        self.assertEqual(serializer.is_valid(), True)
+
 
 class CustomValidationTests(TestCase):
     class CommentSerializerWithFieldValidator(CommentSerializer):