fix: enhance content extraction from chat response to handle multiple generations with null content

Signed-off-by: liugddx <[email protected]>

Author: liugddx

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

@@ -521,10 +521,21 @@ private ChatClientResponse doGetObservableChatClientResponse(ChatClientRequest c
 
 		@Nullable
 		private static String getContentFromChatResponse(@Nullable ChatResponse chatResponse) {
-			return Optional.ofNullable(chatResponse)
-				.map(ChatResponse::getResult)
+			if (chatResponse == null || CollectionUtils.isEmpty(chatResponse.getResults())) {
+				return null;
+			}
+			// Iterate through all generations to find the first one with non-null content
+			// This handles cases where models return multiple generations (e.g., Bedrock
+			// Converse API
+			// with openai.gpt-oss models may return reasoning output first with null
+			// content,
+			// followed by the actual response)
+			return chatResponse.getResults()
+				.stream()
 				.map(Generation::getOutput)
 				.map(AbstractMessage::getText)
+				.filter(text -> text != null)
+				.findFirst()
 				.orElse(null);
 		}
 

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

@@ -969,6 +969,37 @@ void whenChatResponseContentIsNull() {
 		assertThat(content).isNull();
 	}
 
+	@Test
+	void whenMultipleGenerationsWithFirstContentNull() {
+		// Test case for Bedrock Converse API with openai.gpt-oss models
+		// which return multiple generations where the first one has null content
+		// (reasoning output)
+		// and the second one contains the actual response
+		ChatModel chatModel = mock(ChatModel.class);
+		ArgumentCaptor<Prompt> promptCaptor = ArgumentCaptor.forClass(Prompt.class);
+		given(chatModel.call(promptCaptor.capture()))
+			.willReturn(new ChatResponse(List.of(new Generation(new AssistantMessage(null)), // First
+																								// generation
+																								// with
+																								// null
+																								// content
+					new Generation(new AssistantMessage("Hello! How can I help you today?")) // Second
+																								// generation
+																								// with
+																								// actual
+																								// content
+			)));
+
+		ChatClient chatClient = new DefaultChatClientBuilder(chatModel).build();
+		DefaultChatClient.DefaultChatClientRequestSpec chatClientRequestSpec = (DefaultChatClient.DefaultChatClientRequestSpec) chatClient
+			.prompt("Hello");
+		DefaultChatClient.DefaultCallResponseSpec spec = (DefaultChatClient.DefaultCallResponseSpec) chatClientRequestSpec
+			.call();
+
+		String content = spec.content();
+		assertThat(content).isEqualTo("Hello! How can I help you today?");
+	}
+
 	@Test
 	void whenResponseEntityWithParameterizedTypeIsNull() {
 		ChatClient chatClient = new DefaultChatClientBuilder(mock(ChatModel.class)).build();