Add rule SpringAsyncRules.AsyncMethodsNotCalledFromSameClass

src/main/docs/userguide.adoc

@@ -1,4 +1,5 @@
 :toc:
+:toclevels: 4
 :toc-placement!:
 
 = ArchUnit Spring Integration
@@ -100,6 +101,13 @@ It is most convenient that such methods return `void` or an object implementing
 
 If such methods have other return types, Spring may discard the return value or calling such a method may lead to an exception.
 
+===== Rule AsyncMethodsNotCalledFromSameClass
+
+The rule `SpringAsyncRules.AsyncMethodsNotCalledFromSameClass` ensures that methods annotated with `@Async` or `@Asynchronous` are not called from within the same class.
+Such internal calls bypass Spring's proxy mechanism, causing the intended asynchronous behavior to be ignored.
+
+This rule should only be used if caching is used in proxy mode (which is the default mode), see the `@EnableAsync` annotation.
+
 ==== SpringCacheRules
 
 ===== Rule CacheableMethodsAreProxyable

src/main/java/de/rweisleder/archunit/spring/framework/SpringAsyncRules.java

@@ -71,6 +71,18 @@ private SpringAsyncRules() {
             .that(are(annotatedWithAsyncOrAsynchronous()))
             .should(haveRawReturnType(assignableTo(Void.TYPE).or(assignableTo(Future.class))).as("have return type void or java.util.concurrent.Future"));
 
+    /**
+     * A rule that checks that methods annotated with {@code @Async} or {@code @Asynchronous} are not called from within the same class.
+     * Such internal calls bypass Spring's proxy mechanism, causing the intended asynchronous behavior to be ignored.
+     * <p>
+     * This rule should only be used if caching is used in proxy mode, see the {@code @EnableAsync} annotation.
+     *
+     * @see SpringProxyRules#notBeCalledFromWithinTheSameClass()
+     */
+    public static final ArchRule AsyncMethodsNotCalledFromSameClass = methods()
+            .that(are(annotatedWithAsyncOrAsynchronous()))
+            .should(notBeCalledFromWithinTheSameClass());
+
     private static DescribedPredicate<JavaMethod> annotatedWithAsyncOrAsynchronous() {
         DescribedPredicate<JavaMethod> async = springAnnotatedWith("org.springframework.scheduling.annotation.Async").forSubtype();
 

src/test/java/de/rweisleder/archunit/spring/framework/SpringAsyncRulesTest.java

@@ -45,4 +45,14 @@ void provides_a_description() {
             assertThat(description).isEqualTo("methods that are annotated with @Async or @Asynchronous should have return type void or java.util.concurrent.Future");
         }
     }
+
+    @Nested
+    class Rule_AsyncMethodsNotCalledFromSameClass {
+
+        @Test
+        void provides_a_description() {
+            String description = SpringAsyncRules.AsyncMethodsNotCalledFromSameClass.getDescription();
+            assertThat(description).isEqualTo("methods that are annotated with @Async or @Asynchronous should not be called from within the same class");
+        }
+    }
 }