Refs #416 -- Allow combination of GFK and _fill_optional

model_bakery/baker.py

@@ -604,7 +604,7 @@ def _skip_field(self, field: Field) -> bool:
 
         if field.name not in self.model_attrs:
             if field.name not in self.rel_fields and (
-                field.null and not field.fill_optional
+                not field.fill_optional and field.null
             ):
                 return True
 
@@ -671,11 +671,16 @@ def generate_value(self, field: Field, commit: bool = True) -> Any:  # noqa: C90
         `attr_mapping` and `type_mapping` can be defined easily overwriting the
         model.
         """
+        from django.contrib.contenttypes.fields import GenericForeignKey
+
         is_content_type_fk = isinstance(field, ForeignKey) and issubclass(
             self._remote_field(field).model, contenttypes.models.ContentType
         )
+        is_generic_fk = isinstance(field, GenericForeignKey)
         # we only use default unless the field is overwritten in `self.rel_fields`
-        if field.has_default() and field.name not in self.rel_fields:
+        if is_generic_fk:
+            generator = self.type_mapping[contenttypes.models.ContentType]
+        elif field.has_default() and field.name not in self.rel_fields:
             if callable(field.default):
                 return field.default()
             return field.default

tests/test_filling_fields.py

@@ -293,6 +293,11 @@ def test_iteratively_filling_generic_foreign_key_field(self):
         assert dummies[1].content_type == expected_content_type
         assert dummies[1].object_id == objects[1].pk
 
+    def test_with_fill_optional(self):
+        dummy = baker.make(models.DummyGenericForeignKeyModel, _fill_optional=True)
+        assert isinstance(dummy.content_type, ContentType)
+        assert dummy.content_type.model_class() is not None
+
 
 @pytest.mark.django_db
 class TestFillingForeignKeyFieldWithDefaultFunctionReturningId: