Fix crash in annotation value endpoint

when removing the delete markers.

docs/CHANGELOG.rst

@@ -14,10 +14,15 @@ Added
 -----
 - Expose ``status`` on ``collection`` and ``entity`` viewset and allow
   filtering and sorting by it
+
 Changed
 -------
 - Make processing container startup script ``Python`` 3.12 compatible
 
+Fixed
+-----
+- Fix ``AnnotationValueViewSet`` crash when removing the delete markers
+
 
 ===================
 42.0.1 - 2024-11-21

resolwe/flow/models/annotations.py

@@ -517,9 +517,9 @@ def delete_marker(self) -> bool:
         return self._value is None
 
     @property
-    def value(self) -> str | int | float | datetime.date:
-        """Get the actual value."""
-        return self._value["value"]
+    def value(self) -> Optional[str | int | float | datetime.date]:
+        """Get the actual value or None if object is delete marker."""
+        return None if self.delete_marker else self._value["value"]
 
     @value.setter
     def value(self, value: str | int | float | datetime.date):

resolwe/flow/tests/test_annotations.py

@@ -1270,6 +1270,20 @@ def test_list_filter_values(self):
         self.assertTrue(response.data[0]["value"], "string")
         self.assertTrue(response.data[0]["label"], "label string")
 
+        # Test delete markers are handled properly.
+        delete_marker = AnnotationValue.objects.create(
+            entity=self.annotation_value1.entity,
+            field=self.annotation_value1.field,
+            _value=None,
+            contributor=self.annotation_value1.contributor,
+        )
+        request = factory.get("/", {"entity": self.entity1.pk}, format="json")
+        force_authenticate(request, self.contributor)
+        response = self.annotationvalue_viewset(request)
+        self.assertTrue(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(len(response.data), 0)
+        delete_marker.delete()
+
         # Another authenticated request.
         self.annotation_value2.entity = self.entity1
         self.annotation_value2.save()