fix: handle invalid JSON chunk in OpenAiChatModel

Signed-off-by: Minu Kim <[email protected]>

Author: kmw10693

models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiChatModel.java

@@ -329,6 +329,7 @@ public Flux<ChatResponse> internalStream(Prompt prompt, ChatResponse previousCha
 								previousChatResponse);
 						return new ChatResponse(generations, from(chatCompletion2, null, accumulatedUsage));
 					}
+
 					catch (Exception e) {
 						logger.error("Error processing chat completion", e);
 						return new ChatResponse(List.of());
@@ -492,14 +493,20 @@ private ChatResponseMetadata from(ChatResponseMetadata chatResponseMetadata, Usa
 	 * @return the ChatCompletion
 	 */
 	private OpenAiApi.ChatCompletion chunkToChatCompletion(OpenAiApi.ChatCompletionChunk chunk) {
-		List<Choice> choices = chunk.choices()
-			.stream()
-			.map(chunkChoice -> new Choice(chunkChoice.finishReason(), chunkChoice.index(), chunkChoice.delta(),
-					chunkChoice.logprobs()))
-			.toList();
-
-		return new OpenAiApi.ChatCompletion(chunk.id(), choices, chunk.created(), chunk.model(), chunk.serviceTier(),
-				chunk.systemFingerprint(), "chat.completion", chunk.usage());
+		try {
+			List<Choice> choices = chunk.choices()
+				.stream()
+				.map(chunkChoice -> new Choice(chunkChoice.finishReason(), chunkChoice.index(), chunkChoice.delta(),
+						chunkChoice.logprobs()))
+				.toList();
+
+			return new OpenAiApi.ChatCompletion(chunk.id(), choices, chunk.created(), chunk.model(),
+					chunk.serviceTier(), chunk.systemFingerprint(), "chat.completion", chunk.usage());
+		}
+		catch (Exception e) {
+			logger.warn("Invalid JSON chunk received, skipping. Raw chunk: {}", chunk, e);
+			throw new RuntimeException("Failed to parse ChatCompletionChunk", e);
+		}
 	}
 
 	private DefaultUsage getDefaultUsage(OpenAiApi.Usage usage) {

models/spring-ai-openai/src/test/java/org/springframework/ai/openai/OpenAiChatModelStreamingTest.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2025-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.ai.openai;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+import reactor.core.publisher.Flux;
+
+import org.springframework.ai.chat.prompt.Prompt;
+import org.springframework.ai.openai.api.OpenAiApi;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.when;
+
+public class OpenAiChatModelStreamingTest {
+
+	@Test
+	void shouldThrowExceptionOnInvalidJsonChunk() {
+		OpenAiApi mockApi = Mockito.mock(OpenAiApi.class);
+
+		OpenAiApi.ChatCompletionChunk invalidChunk = new OpenAiApi.ChatCompletionChunk("invalid-id", null,
+				System.currentTimeMillis() / 1000L, "gpt-test-model", null, null, null, null);
+
+		when(mockApi.chatCompletionStream(any(), any())).thenReturn(Flux.just(invalidChunk));
+
+		OpenAiChatOptions options = OpenAiChatOptions.builder().model("gpt-test-model").build();
+		OpenAiChatModel model = OpenAiChatModel.builder().openAiApi(mockApi).defaultOptions(options).build();
+
+		assertThatThrownBy(() -> model.stream(new Prompt("Hello")).collectList().block())
+			.isInstanceOf(RuntimeException.class)
+			.hasMessageContaining("Failed to parse ChatCompletionChunk");
+	}
+
+}