Fix schema with relationship to dump None (#302)

* Fix schema with relationship to dump None

* Revert gitignore change (.idea belongs in global gitignore)

* Fix test

* Update changelog

Co-authored-by: Steven Loria <sloria1@gmail.com>

Author: mahenzon

CHANGELOG.rst

@@ -9,6 +9,10 @@ Deprecations/Removals:
 
 * Drop support for marshmallow 2, which is now EOL (:pr:`332`).
 
+Bug fixes:
+
+* Fix behavior when serializing ``None`` (:pr:`302`). Thanks :user:`mahenzon`.
+
 Other changes:
 
 * Test against Python 3.8 and 3.9 (:pr:`332`).

marshmallow_jsonapi/fields.py

@@ -244,7 +244,7 @@ def _deserialize(self, value, attr, obj, **kwargs):
     # in the request. And we don't have enough control in _serialize
     # to prevent their serialization
     def serialize(self, attr, obj, accessor=None):
-        if self.include_resource_linkage or self.include_data:
+        if obj is None or self.include_resource_linkage or self.include_data:
             return super().serialize(attr, obj, accessor)
         return self._serialize(None, attr, obj)
 

tests/test_schema.py

@@ -96,6 +96,10 @@ def test_dump_none(self):
         assert data["data"] is None
         assert "links" not in data
 
+    def test_schema_with_relationship_processes_none(self):
+        data = CommentSchema().dump(None)
+        assert data == {"data": None}
+
     def test_dump_empty_list(self):
         data = AuthorSchema(many=True).dump([])