Remove symmetrical doc links when entire custom field removed

src/documents/serialisers.py

@@ -608,6 +608,21 @@ class DocumentSerializer(
             instance.save()
         if "created_date" in validated_data:
             validated_data.pop("created_date")
+        if instance.custom_fields.count() > 0 and "custom_fields" in validated_data:
+            for custom_field_instance in instance.custom_fields.filter(
+                field__data_type=CustomField.FieldDataType.DOCUMENTLINK,
+            ):
+                if custom_field_instance.field not in [
+                    field["field"] for field in validated_data["custom_fields"]
+                ]:
+                    # Doc link field is being removed entirely
+                    for doc_id in custom_field_instance.value:
+                        CustomFieldInstanceSerializer.remove_doclink(
+                            None,
+                            instance,
+                            custom_field_instance.field,
+                            doc_id,
+                        )
         super().update(instance, validated_data)
         return instance
 

src/documents/tests/test_api_custom_fields.py

@@ -476,3 +476,17 @@ class TestCustomField(DirectoriesMixin, APITestCase):
         self.assertEqual(doc2.custom_fields.first().value, [1])
         self.assertEqual(doc3.custom_fields.first().value, [1])
         self.assertEqual(doc4.custom_fields.first().value, [])
+
+        # Removes the field entirely
+        resp = self.client.patch(
+            f"/api/documents/{doc1.id}/",
+            data={
+                "custom_fields": [],
+            },
+            format="json",
+        )
+
+        self.assertEqual(resp.status_code, status.HTTP_200_OK)
+        self.assertEqual(doc2.custom_fields.first().value, [])
+        self.assertEqual(doc3.custom_fields.first().value, [])
+        self.assertEqual(doc4.custom_fields.first().value, [])