Fix scope leak in ObservedAspect

micrometer-observation/src/main/java/io/micrometer/observation/aop/ObservedAspect.java

@@ -71,6 +71,7 @@
  * @author Jonatan Ivanov
  * @author Yanming Zhou
  * @author Jeonggi Kim
+ * @author Maksim Petelin
  * @since 1.10.0
  */
 @Aspect
@@ -151,16 +152,16 @@ private Object observe(ProceedingJoinPoint pjp, Method method, Observed observed
             try {
                 Object result = pjp.proceed();
                 if (result == null) {
-                    stopObservation(observation, scope, null);
+                    stopObservation(observation, null);
                     return result;
                 }
                 else {
                     CompletionStage<?> stage = (CompletionStage<?>) result;
-                    return stage.whenComplete((res, error) -> stopObservation(observation, scope, error));
+                    return stage.whenComplete((res, error) -> stopObservation(observation, error));
                 }
             }
             catch (Throwable error) {
-                stopObservation(observation, scope, error);
+                stopObservation(observation, error);
                 throw error;
             }
             finally {
@@ -191,11 +192,10 @@ private Method getMethod(ProceedingJoinPoint pjp) throws NoSuchMethodException {
         return method;
     }
 
-    private void stopObservation(Observation observation, Observation.Scope scope, @Nullable Throwable error) {
+    private void stopObservation(Observation observation, @Nullable Throwable error) {
         if (error != null) {
             observation.error(error);
         }
-        scope.close();
         observation.stop();
     }
 

samples/micrometer-samples-spring-framework6/src/test/java/io/micrometer/samples/spring6/aop/ObservedAspectTests.java

@@ -170,6 +170,26 @@ void annotatedAsyncCallShouldBeObservedAndErrorRecorded() {
             .isEqualTo(simulatedException);
     }
 
+    @Test
+    void observationShouldNotLeakToFutureCompletionThread() {
+        registry.observationConfig().observationHandler(new ObservationTextPublisher());
+
+        AspectJProxyFactory pf = new AspectJProxyFactory(new ObservedService());
+        pf.addAspect(new ObservedAspect(registry));
+
+        ObservedService service = pf.getProxy();
+        FakeAsyncTask fakeAsyncTask = new FakeAsyncTask("test-result");
+
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+        CompletableFuture<String> asyncResult = service.supply(() -> service.async(fakeAsyncTask, executor));
+        // must run in the thread of the executor (async task)
+        CompletableFuture<Void> asyncAssertion = asyncResult
+            .thenRunAsync(() -> assertThat(registry).doesNotHaveAnyRemainingCurrentObservation(), executor);
+        fakeAsyncTask.proceed();
+
+        assertThat(asyncAssertion).succeedsWithin(Duration.ofMillis(200));
+    }
+
     @Test
     void customObservationConventionShouldBeUsed() {
         registry.observationConfig().observationHandler(new ObservationTextPublisher());
@@ -392,14 +412,28 @@ void error() {
 
         @Observed(name = "test.async")
         CompletableFuture<String> async(FakeAsyncTask fakeAsyncTask) {
-            System.out.println("async");
             ContextSnapshot contextSnapshot = ContextSnapshotFactory.builder()
                 .captureKeyPredicate(key -> true)
                 .contextRegistry(ContextRegistry.getInstance())
                 .build()
                 .captureAll();
-            return CompletableFuture.supplyAsync(fakeAsyncTask,
-                    contextSnapshot.wrapExecutor(Executors.newSingleThreadExecutor()));
+            return supplyAsync(fakeAsyncTask, contextSnapshot.wrapExecutor(Executors.newSingleThreadExecutor()));
+        }
+
+        @Observed(name = "test.async")
+        CompletableFuture<String> async(FakeAsyncTask fakeAsyncTask, Executor singleThreadExecutor) {
+            return supplyAsync(fakeAsyncTask, singleThreadExecutor);
+        }
+
+        @Observed(name = "test.supply")
+        <T> T supply(Supplier<T> supplier) {
+            System.out.println("supply");
+            return supplier.get();
+        }
+
+        private CompletableFuture<String> supplyAsync(FakeAsyncTask fakeAsyncTask, Executor executor) {
+            System.out.println("async");
+            return CompletableFuture.supplyAsync(fakeAsyncTask, executor);
         }
 
     }