Fix default target destination when using "." as path separator

Issue: SPR-11660

spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SendToMethodReturnValueHandler.java

@@ -32,6 +32,7 @@ import org.springframework.messaging.simp.user.DestinationUserNameProvider;
 import org.springframework.messaging.support.MessageHeaderInitializer;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
+import org.springframework.util.StringUtils;
 
 import java.lang.annotation.Annotation;
 import java.security.Principal;
@@ -187,7 +188,11 @@ public class SendToMethodReturnValueHandler implements HandlerMethodReturnValueH
 			}
 		}
 		String name = DestinationPatternsMessageCondition.LOOKUP_DESTINATION_HEADER;
-		return new String[] { defaultPrefix + message.getHeaders().get(name) };
+		String destination = (String)message.getHeaders().get(name);
+		if (StringUtils.hasLength(destination) && !destination.startsWith("/")) {
+			destination = "/" + destination;
+		}
+		return new String[] { defaultPrefix + destination };
 	}
 
 	private MessageHeaders createHeaders(String sessionId) {

spring-messaging/src/test/java/org/springframework/messaging/simp/annotation/support/SendToMethodReturnValueHandlerTests.java

@@ -185,6 +185,21 @@ public class SendToMethodReturnValueHandlerTests {
 		assertNull("Subscription id should not be copied", headers.getSubscriptionId());
 	}
 
+	@Test
+	public void sendToDefaultDestinationWithoutLeadingSlash() throws Exception {
+
+		when(this.messageChannel.send(any(Message.class))).thenReturn(true);
+
+		Message<?> inputMessage = createInputMessage("sess1", "sub1", "/app", "dest", null);
+		this.handler.handleReturnValue(PAYLOAD, this.sendToDefaultDestReturnType, inputMessage);
+
+		verify(this.messageChannel, times(1)).send(this.messageCaptor.capture());
+
+		Message<?> message = this.messageCaptor.getAllValues().get(0);
+		SimpMessageHeaderAccessor headers = SimpMessageHeaderAccessor.wrap(message);
+		assertEquals("/topic/dest", headers.getDestination());
+	}
+
 	@Test
 	public void testHeadersToSend() throws Exception {
 
@@ -297,6 +312,22 @@ public class SendToMethodReturnValueHandlerTests {
 		assertEquals("/user/" + user.getName() + "/queue/dest", headers.getDestination());
 	}
 
+	@Test
+	public void sendToUserDefaultDestinationWithoutLeadingSlash() throws Exception {
+
+		when(this.messageChannel.send(any(Message.class))).thenReturn(true);
+
+		TestUser user = new TestUser();
+		Message<?> inputMessage = createInputMessage("sess1", "sub1", "/app", "dest", user);
+		this.handler.handleReturnValue(PAYLOAD, this.sendToUserDefaultDestReturnType, inputMessage);
+
+		verify(this.messageChannel, times(1)).send(this.messageCaptor.capture());
+
+		Message<?> message = this.messageCaptor.getAllValues().get(0);
+		SimpMessageHeaderAccessor headers = SimpMessageHeaderAccessor.wrap(message);
+		assertEquals("/user/" + user.getName() + "/queue/dest", headers.getDestination());
+	}
+
 	@Test
 	public void sendToUserDefaultDestinationSingleSession() throws Exception {