  
          missing_items = {
              field_name: self.missing_message
              for field_name in self.fields
              if field_name not in attrs
          }
          if missing_items:
              raise ValidationError(missing_items, code='required')
  
      def filter_queryset(self, attrs, queryset, serializer):
 
</s> remove             field_name: attrs[field_name]
            for field_name in self.fields
 </s> add             source: attrs[source]
            for source in sources </s> remove             for field_name in self.fields:
                if field_name not in attrs:
                    attrs[field_name] = getattr(serializer.instance, field_name)
 </s> add             for source in sources:
                if source not in attrs:
                    attrs[source] = getattr(serializer.instance, source) </s> remove         class MockSerializer:
            def __init__(self, instance):
                self.instance = instance

 </s> add  </s> remove             defaults[field.field_name] = default
 </s> add             defaults[field.source] = default
            if serializer.fields[field_name].source not in attrs
  
          missing_items = {
              field_name: self.missing_message
              for field_name in self.fields
            if serializer.fields[field_name].source not in attrs
          }
          if missing_items:
              raise ValidationError(missing_items, code='required')
  
      def filter_queryset(self, attrs, queryset, serializer):
keep keep keep keep replace keep keep keep keep keep
 Fix UniqueTogetherValidator with field sources (#7086)

* Add failing tests for unique_together+source

* Fix UniqueTogetherValidator source handling

* Fix read-only+default+source handling

* Update test to use functional serializer

* Test UniqueTogetherValidator error+source 
rest_framework/validators.py