Use setattr for adding fields to a new instance

Add test for restoring a GenericForeignKey

1 files changed, 8 insertions, 10 deletions

diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index 1d6097ed..ea9509bf 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -955,17 +955,15 @@ class ModelSerializer(Serializer):
             if isinstance(self.fields.get(field_name, None), Serializer):
                 nested_forward_relations[field_name] = attrs[field_name]
 
-        # Update an existing instance...
-        if instance is not None:
-            for key, val in attrs.items():
-                try:
-                    setattr(instance, key, val)
-                except ValueError:
-                    self._errors[key] = self.error_messages['required']
+        # Create an empty instance of the model
+        if instance is None:
+            instance = self.opts.model()
 
-        # ...or create a new instance
-        else:
-            instance = self.opts.model(**attrs)
+        for key, val in attrs.items():
+            try:
+                setattr(instance, key, val)
+            except ValueError:
+                self._errors[key] = self.error_messages['required']
 
         # Any relations that cannot be set until we've
         # saved the model get hidden away on these