Make reranker more robust

app.py

@@ -57,7 +57,11 @@ def rag_pipeline(query):
     retrieved_docs = [corpus[idx] for idx in I[0]]
 
     # Rerank
-    rerank_pairs = [[query, doc] for doc in retrieved_docs]
+    rerank_pairs = [[str(query), str(doc)] for doc in retrieved_docs if isinstance(doc, str) and doc.strip()]
+    if not rerank_pairs:
+        return "No valid documents found to rerank."
+    scores = reranker.predict(rerank_pairs)
+
     scores = reranker.predict(rerank_pairs)
     reranked_docs = [doc for _, doc in sorted(zip(scores, retrieved_docs), reverse=True)]