From c184cfdfd1b19a3ac9e9c510406a65819381e7dd Mon Sep 17 00:00:00 2001
From: yangkaijun <yangkaijun@eastmoney.com>
Date: Tue, 27 May 2025 17:44:50 +0800
Subject: [PATCH] fix(ai-rag): Fix query expansion result handling logic, same
 as #3345

- Filter out empty strings from query expansion results
- Optimize the logic for checking the number of query variants
---
 .../preretrieval/query/expansion/MultiQueryExpander.java    | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/spring-ai-rag/src/main/java/org/springframework/ai/rag/preretrieval/query/expansion/MultiQueryExpander.java b/spring-ai-rag/src/main/java/org/springframework/ai/rag/preretrieval/query/expansion/MultiQueryExpander.java
index 314a455ba25..101750a5b27 100644
--- a/spring-ai-rag/src/main/java/org/springframework/ai/rag/preretrieval/query/expansion/MultiQueryExpander.java
+++ b/spring-ai-rag/src/main/java/org/springframework/ai/rag/preretrieval/query/expansion/MultiQueryExpander.java
@@ -111,9 +111,11 @@ public List<Query> expand(Query query) {
 			return List.of(query);
 		}
 
-		var queryVariants = Arrays.asList(response.split("\n"));
+		var queryVariants = Arrays.stream(response.split("\n"))
+				.filter(StringUtils::hasText)
+				.toList();
 
-		if (CollectionUtils.isEmpty(queryVariants) || this.numberOfQueries != queryVariants.size()) {
+		if (CollectionUtils.isEmpty(queryVariants) || this.numberOfQueries > queryVariants.size()) {
 			logger.warn(
 					"Query expansion result does not contain the requested {} variants. Returning the input query unchanged.",
 					this.numberOfQueries);