Fix @SubscribeMapping MESSAGE response destination

Prior to this commit, @SubscribeMapping mapped methods (backed with
@SendTo* annotations, or not) would send MESSAGEs with the wrong
destination. Instead of using the original SUBSCRIBE destination, it
would use the lookup path computed from the configured prefixes in the
application.

This commit fixes this issue - now @SubscribeMapping MESSAGEs use the
original SUBSCRIBE destination.

Issue: SPR-11648

spring-websocket/src/test/java/org/springframework/web/socket/messaging/StompWebSocketIntegrationTests.java

@@ -36,6 +36,7 @@ import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.messaging.handler.annotation.MessageExceptionHandler;
 import org.springframework.messaging.handler.annotation.MessageMapping;
+import org.springframework.messaging.simp.annotation.SubscribeMapping;
 import org.springframework.messaging.simp.config.MessageBrokerRegistry;
 import org.springframework.messaging.simp.stomp.StompCommand;
 import org.springframework.messaging.support.AbstractSubscribableChannel;
@@ -134,6 +135,28 @@ public class StompWebSocketIntegrationTests extends AbstractWebSocketIntegration
 		}
 	}
 
+	// SPR-11648
+
+	@Test
+	public void sendSubscribeToControllerAndReceiveReply() throws Exception {
+
+		TextMessage message = create(StompCommand.SUBSCRIBE).headers(
+				"id:subs1", "destination:/app/number").build();
+
+		TestClientWebSocketHandler clientHandler = new TestClientWebSocketHandler(1, message);
+		WebSocketSession session = doHandshake(clientHandler, "/ws").get();
+
+		try {
+			assertTrue(clientHandler.latch.await(2, TimeUnit.SECONDS));
+			String payload = clientHandler.actual.get(0).getPayload();
+			assertTrue("Expected STOMP destination=/app/number, got " + payload, payload.contains("destination:/app/number"));
+			assertTrue("Expected STOMP Payload=42, got " + payload, payload.contains("42"));
+		}
+		finally {
+			session.close();
+		}
+	}
+
 
 	@IntegrationTestController
 	static class SimpleController {
@@ -164,6 +187,11 @@ public class StompWebSocketIntegrationTests extends AbstractWebSocketIntegration
 		public int handle(int i) {
 			return i + 1;
 		}
+
+		@SubscribeMapping("/number")
+		public int number() {
+			return 42;
+		}
 	}