fix(variants): don't raise Recursive error when creating big variant …

…tree

antarest/study/storage/variantstudy/model/model.py

@@ -1,4 +1,4 @@
-from typing import List, Optional, Tuple, Union
+from typing import List, NamedTuple, Optional, Tuple, Union
 
 from pydantic import BaseModel
 
@@ -26,9 +26,7 @@ class CommandResultDTO(BaseModel):
     message: str
 
 
-class VariantTreeDTO(BaseModel):
+class VariantTreeDTO(NamedTuple):
+    # Don't use BaseModel as this could trigger Recursion exceptions, since we're using Pydantic with a version prior to v2.
     node: StudyMetadataDTO
     children: List["VariantTreeDTO"]
-
-
-VariantTreeDTO.update_forward_refs()

tests/integration/variant_blueprint/test_variant_manager.py

@@ -1,4 +1,6 @@
 import logging
+import random
+import string
 
 from starlette.testclient import TestClient
 
@@ -186,3 +188,16 @@ def test_variant_manager(client: TestClient, admin_access_token: str, study_id:
 
         res = client.get(f"/v1/studies/{variant_id}", headers=admin_headers)
         assert res.status_code == 404
+
+
+def test_recursive_variant_tree(client: TestClient, admin_access_token: str):
+    admin_headers = {"Authorization": f"Bearer {admin_access_token}"}
+    base_study_res = client.post("/v1/studies?name=foo", headers=admin_headers)
+    base_study_id = base_study_res.json()
+    parent_id = base_study_res.json()
+    for k in range(150):
+        res = client.post(f"/v1/studies/{base_study_id}/variants?name=variant_{k}", headers=admin_headers)
+        base_study_id = res.json()
+    # Asserts that we do not trigger a Recursive Exception
+    res = client.get(f"/v1/studies/{parent_id}/variants", headers=admin_headers)
+    assert res.status_code == 200