From 58d68ac7c6153112b4abe925ba7be1a9dad640be Mon Sep 17 00:00:00 2001
From: JINO ROHIT <find.jinorohit@gmail.com>
Date: Tue, 10 Dec 2024 14:24:41 +0530
Subject: [PATCH] raises error when dataset is an empty list in
 NanoBEIREvaluator (#3122)

* raises error when dataset is an empty list in NanoBEIREvaluator

* fix len
---
 sentence_transformers/evaluation/NanoBEIREvaluator.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sentence_transformers/evaluation/NanoBEIREvaluator.py b/sentence_transformers/evaluation/NanoBEIREvaluator.py
index ec29ad094..82907e3ed 100644
--- a/sentence_transformers/evaluation/NanoBEIREvaluator.py
+++ b/sentence_transformers/evaluation/NanoBEIREvaluator.py
@@ -420,6 +420,8 @@ def _load_dataset(self, dataset_name: DatasetNameType, **ir_evaluator_kwargs) ->
         )
 
     def _validate_dataset_names(self):
+        if len(self.dataset_names) == 0:
+            raise ValueError("dataset_names cannot be empty. Use None to evaluate on all datasets.")
         if missing_datasets := [
             dataset_name for dataset_name in self.dataset_names if dataset_name.lower() not in dataset_name_to_id
         ]: