GH-484 - Let CompletionRegisteringAdvisor forward EventExternalized event.

Author: odrotbohm

spring-modulith-events/spring-modulith-events-core/src/main/java/org/springframework/modulith/events/support/CompletionRegisteringAdvisor.java

@@ -175,7 +175,10 @@ public Object invoke(MethodInvocation invocation) throws Throwable {
 				if (result instanceof CompletableFuture<?> future) {
 
 					return future
-							.thenAccept(it -> markCompleted(method, argument))
+							.thenApply(it -> {
+								markCompleted(method, argument);
+								return it;
+							})
 							.exceptionallyCompose(it -> {
 								handleFailure(method, it);
 								return CompletableFuture.failedFuture(it);

spring-modulith-events/spring-modulith-events-core/src/test/java/org/springframework/modulith/events/support/CompletionRegisteringAdvisorUnitTests.java

@@ -89,6 +89,14 @@ void marksLazilyComputedCompletableFutureAsCompleted() throws Throwable {
 		verify(registry).markCompleted(any(), any());
 	}
 
+	@Test // GH-484
+	void exposesResultForCompletableFuture() throws Exception {
+
+		CompletableFuture<?> future = createProxyFor(bean).asyncWithResult(false);
+
+		assertThat(future.get()).isNotNull();
+	}
+
 	private void assertCompletion(BiConsumer<SomeEventListener, Object> consumer) {
 		assertCompletion(consumer, true);
 	}