Small QoL for qa. (#21316)

src/transformers/pipelines/question_answering.py

@@ -404,6 +404,9 @@ class QuestionAnsweringPipeline(ChunkPipeline):
         if doc_stride is None:
             doc_stride = min(max_seq_len // 2, 128)
 
+        if doc_stride > max_seq_len:
+            raise ValueError(f"`doc_stride` ({doc_stride}) is larger than `max_seq_len` ({max_seq_len})")
+
         if not self.tokenizer.is_fast:
             features = squad_convert_examples_to_features(
                 examples=[example],