fixing unique together validator for fields with source

rest_framework/validators.py

@@ -107,6 +107,7 @@ def set_context(self, serializer):
         """
         # Determine the existing instance, if this is an update operation.
         self.instance = getattr(serializer, 'instance', None)
+        self.serializer = serializer
 
     def enforce_required_fields(self, attrs):
         """
@@ -133,12 +134,24 @@ def filter_queryset(self, attrs, queryset):
         if self.instance is not None:
             for field_name in self.fields:
                 if field_name not in attrs:
-                    attrs[field_name] = getattr(self.instance, field_name)
+                    if field_name == self.serializer.fields[field_name].source:
+                        attrs[field_name] = getattr(self.instance, field_name)
+                    else:
+                        attrs[self.serializer.fields[field_name].source] = getattr(self.instance, self.serializer.fields[field_name].source)
+
 
         # Determine the filter keyword arguments and filter the queryset.
         filter_kwargs = {
-            field_name: attrs[field_name]
-            for field_name in self.fields
+            (
+                field_name
+                if field_name == self.serializer.fields[field_name].source
+                else self.serializer.fields[field_name].source
+                ): (
+                    attrs[field_name]
+                    if self.instance is None or not self.serializer.partial
+                    else attrs[self.serializer.fields[field_name].source]
+                )
+                for field_name in self.fields
         }
         return qs_filter(queryset, **filter_kwargs)
 

tests/test_validators.py

@@ -365,6 +365,40 @@ def filter(self, **kwargs):
         validator.filter_queryset(attrs=data, queryset=queryset)
         assert queryset.called_with == {'race_name': 'bar', 'position': 1}
 
+class WritableFieldsWithSourceSerializer(serializers.ModelSerializer):
+    name = serializers.CharField(source='race_name')
+
+    class Meta:
+        model = UniquenessTogetherModel
+        fields = ['name', 'position']
+        validators = [
+            UniqueTogetherValidator(
+                queryset=UniquenessTogetherModel.objects.all(),
+                fields=['name', 'position']
+            )
+        ]
+
+class ReadOnlyFieldsWithSourceSerializer(serializers.ModelSerializer):
+    name = serializers.CharField(source='race_name', read_only=True, default='test')
+
+    class Meta:
+        model = UniquenessTogetherModel
+        fields = ['name', 'position']
+        validators = [
+            UniqueTogetherValidator(
+                queryset=UniquenessTogetherModel.objects.all(),
+                fields=['name', 'position']
+            )
+        ]
+
+class TestFieldsWithFieldSource(TestCase):
+    def test_writeable(self):
+        serializer = WritableFieldsWithSourceSerializer(data={'name': 'formula1', 'position': '1'})
+        serializer.is_valid(raise_exception=True)
+
+    def test_read_only(self):
+        serializer = ReadOnlyFieldsWithSourceSerializer(data={'position': '1'})
+        serializer.is_valid(raise_exception=True)
 
 # Tests for `UniqueForDateValidator`
 # ----------------------------------