Fix VectorStoreChatMemoryAdvisor streaming bug

- Override adviseStream method in VectorStoreChatMemoryAdvisor to properly handle streaming responses
- Add tests to verify the fix works with both normal and problematic streaming scenarios

Fixes #3152

Signed-off-by: Mark Pollack <mark.pollack@broadcom.com>

advisors/spring-ai-advisors-vector-store/src/main/java/org/springframework/ai/chat/client/advisor/vectorstore/VectorStoreChatMemoryAdvisor.java

@@ -21,14 +21,18 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
 import reactor.core.scheduler.Scheduler;
 
+import org.springframework.ai.chat.client.ChatClientMessageAggregator;
 import org.springframework.ai.chat.client.ChatClientRequest;
 import org.springframework.ai.chat.client.ChatClientResponse;
 import org.springframework.ai.chat.client.advisor.api.Advisor;
 import org.springframework.ai.chat.client.advisor.api.AdvisorChain;
 import org.springframework.ai.chat.client.advisor.api.BaseAdvisor;
 import org.springframework.ai.chat.client.advisor.api.BaseChatMemoryAdvisor;
+import org.springframework.ai.chat.client.advisor.api.StreamAdvisorChain;
 import org.springframework.ai.chat.memory.ChatMemory;
 import org.springframework.ai.chat.messages.AssistantMessage;
 import org.springframework.ai.chat.messages.Message;
@@ -167,6 +171,20 @@ public final class VectorStoreChatMemoryAdvisor implements BaseChatMemoryAdvisor
 		return chatClientResponse;
 	}
 
+	@Override
+	public Flux<ChatClientResponse> adviseStream(ChatClientRequest chatClientRequest,
+			StreamAdvisorChain streamAdvisorChain) {
+		// Get the scheduler from BaseAdvisor
+		Scheduler scheduler = this.getScheduler();
+		// Process the request with the before method
+		return Mono.just(chatClientRequest)
+			.publishOn(scheduler)
+			.map(request -> this.before(request, streamAdvisorChain))
+			.flatMapMany(streamAdvisorChain::nextStream)
+			.transform(flux -> new ChatClientMessageAggregator().aggregateChatClientResponse(flux,
+					response -> this.after(response, streamAdvisorChain)));
+	}
+
 	private List<Document> toDocuments(List<Message> messages, String conversationId) {
 		List<Document> docs = messages.stream()
 			.filter(m -> m.getMessageType() == MessageType.USER || m.getMessageType() == MessageType.ASSISTANT)

vector-stores/spring-ai-pgvector-store/src/test/java/org/springframework/ai/vectorstore/pgvector/PgVectorStoreWithChatMemoryAdvisorIT.java

@@ -47,6 +47,7 @@ import org.springframework.ai.vectorstore.SearchRequest;
 import org.springframework.jdbc.core.JdbcTemplate;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;