Merge branch 'gregmuellegger-fixes/2013'

rest_framework/serializers.py

@@ -653,7 +653,24 @@ class ModelSerializer(Serializer):
             if relation_info.to_many and (field_name in validated_attrs):
                 many_to_many[field_name] = validated_attrs.pop(field_name)
 
-        instance = ModelClass.objects.create(**validated_attrs)
+        try:
+            instance = ModelClass.objects.create(**validated_attrs)
+        except TypeError as exc:
+            msg = (
+                'Got a `TypeError` when calling `%s.objects.create()`. '
+                'This may be because you have a writable field on the '
+                'serializer class that is not a valid argument to '
+                '`%s.objects.create()`. You may need to make the field '
+                'read-only, or override the %s.create() method to handle '
+                'this correctly.\nOriginal exception text was: %s.' %
+                (
+                    ModelClass.__name__,
+                    ModelClass.__name__,
+                    self.__class__.__name__,
+                    exc
+                )
+            )
+            raise TypeError(msg)
 
         # Save many-to-many relationships after the instance is created.
         if many_to_many:

tests/test_model_serializer.py

@@ -26,6 +26,10 @@ class CustomField(models.Field):
     pass
 
 
+class OneFieldModel(models.Model):
+    char_field = models.CharField(max_length=100)
+
+
 class RegularFieldsModel(models.Model):
     """
     A model class for testing regular flat fields.
@@ -68,6 +72,26 @@ class FieldOptionsModel(models.Model):
     choices_field = models.CharField(max_length=100, choices=COLOR_CHOICES)
 
 
+class TestModelSerializer(TestCase):
+    def test_create_method(self):
+        class TestSerializer(serializers.ModelSerializer):
+            non_model_field = serializers.CharField()
+
+            class Meta:
+                model = OneFieldModel
+                fields = ('char_field', 'non_model_field')
+
+        serializer = TestSerializer(data={
+            'char_field': 'foo',
+            'non_model_field': 'bar',
+        })
+        serializer.is_valid()
+        with self.assertRaises(TypeError) as excinfo:
+            serializer.save()
+        msginitial = 'Got a `TypeError` when calling `OneFieldModel.objects.create()`.'
+        assert str(excinfo.exception).startswith(msginitial)
+
+
 class TestRegularFieldMappings(TestCase):
     def test_regular_fields(self):
         """