fix:Advisor parameters lost when mutate ChatClient

- Fixed issue where advisor parameters were lost when advisors were not present during ChatClient mutation.
- Added test case mutateAdvisorParams to ensure correct parameter mutation handling.

Signed-off-by: YunKui Lu <[email protected]>

Author: YunKuiLu

spring-ai-client-chat/src/main/java/org/springframework/ai/chat/client/DefaultChatClient.java

@@ -820,7 +820,11 @@ public Builder mutate() {
 				.defaultToolNames(StringUtils.toStringArray(this.toolNames));
 
 			if (!CollectionUtils.isEmpty(this.advisors)) {
-				builder.defaultAdvisors(a -> a.advisors(this.advisors).params(this.advisorParams));
+				builder.defaultAdvisors(a -> a.advisors(this.advisors));
+			}
+
+			if (!CollectionUtils.isEmpty(this.advisorParams)) {
+				builder.defaultAdvisors(a -> a.params(this.advisorParams));
 			}
 
 			if (StringUtils.hasText(this.userText)) {

spring-ai-client-chat/src/test/java/org/springframework/ai/chat/client/ChatClientTests.java

@@ -408,6 +408,21 @@ void mutateDefaults() {
 
 	}
 
+	@Test
+	void mutateAdvisorParams() {
+		ChatClient defaultChatClient = ChatClient.builder(this.chatModel)
+				.defaultAdvisors(AdvisorParams.ENABLE_NATIVE_STRUCTURED_OUTPUT)
+				.build();
+
+		ChatClient mutatedChatClient = defaultChatClient.mutate()
+				.build();
+
+		ChatClient.ChatClientRequestSpec prompt = mutatedChatClient.prompt();
+
+		assertThat(((DefaultChatClient.DefaultChatClientRequestSpec) prompt).getAdvisorParams())
+				.containsKey(ChatClientAttributes.STRUCTURED_OUTPUT_NATIVE.getKey());
+	}
+
 	@Test
 	void mutatePrompt() {