Rerank Handle Null (#2010)

backend/danswer/db/engine.py

@@ -36,7 +36,7 @@ POSTGRES_APP_NAME = (
 _SYNC_ENGINE: Engine | None = None
 _ASYNC_ENGINE: AsyncEngine | None = None
 
-SessionFactory = None
+SessionFactory: sessionmaker[Session] | None = None
 
 
 def get_db_current_time(db_session: Session) -> datetime:

backend/danswer/search/postprocessing/postprocessing.py

@@ -236,6 +236,12 @@ def search_postprocessing(
 ) -> Iterator[list[InferenceSection] | list[int]]:
     post_processing_tasks: list[FunctionCall] = []
 
+    if not retrieved_sections:
+        # Avoids trying to rerank an empty list which throws an error
+        yield []
+        yield []
+        return
+
     rerank_task_id = None
     sections_yielded = False
     if should_rerank(search_query):