DuplicateRenderCallsAreIgnored

lib/ui/fixtures/ui_test.dart

@@ -1077,14 +1077,19 @@ external void _callHook(
   Object? arg21,
 ]);
 
-Picture CreateRedBox(Size size) {
-  Paint paint = Paint()
+Scene CreateRedBoxScene(Size size) {
+  final SceneBuilder builder = SceneBuilder();
+  builder.pushOffset(0.0, 0.0);
+  final Paint paint = Paint()
     ..color = Color.fromARGB(255, 255, 0, 0)
     ..style = PaintingStyle.fill;
-  PictureRecorder baseRecorder = PictureRecorder();
-  Canvas canvas = Canvas(baseRecorder);
+  final PictureRecorder baseRecorder = PictureRecorder();
+  final Canvas canvas = Canvas(baseRecorder);
   canvas.drawRect(Rect.fromLTRB(0.0, 0.0, size.width, size.height), paint);
-  return baseRecorder.endRecording();
+  final Picture picture = baseRecorder.endRecording();
+  builder.addPicture(Offset(0.0, 0.0), picture);
+  builder.pop();
+  return builder.build();
 }
 
 @pragma('vm:entry-point')
@@ -1093,11 +1098,17 @@ external void notifyNative();
 
 @pragma('vm:entry-point')
 void incorrectImmediateRender() {
-  SceneBuilder builder = SceneBuilder();
-  builder.pushOffset(0.0, 0.0);
-  builder.addPicture(Offset(0.0, 0.0), CreateRedBox(Size(2.0, 2.0)));
-  builder.pop();
-  PlatformDispatcher.instance.views.first.render(builder.build());
-  PlatformDispatcher.instance.scheduleFrame();
-  notifyNative();
+  PlatformDispatcher.instance.views.first.render(CreateRedBoxScene(Size(2, 2)));
+}
+
+@pragma('vm:entry-point')
+void incorrectDoubleRender() {
+  PlatformDispatcher.instance.onBeginFrame = (Duration value) {
+    PlatformDispatcher.instance.views.first.render(CreateRedBoxScene(Size(2, 2)));
+    PlatformDispatcher.instance.views.first.render(CreateRedBoxScene(Size(3, 3)));
+  };
+  PlatformDispatcher.instance.onDrawFrame = () {
+    PlatformDispatcher.instance.views.first.render(CreateRedBoxScene(Size(4, 4)));
+    PlatformDispatcher.instance.views.first.render(CreateRedBoxScene(Size(5, 5)));
+  };
 }

lib/ui/window/platform_configuration_unittests.cc

@@ -444,7 +444,7 @@ TEST_F(PlatformConfigurationTest, SetDartPerformanceMode) {
   DestroyShell(std::move(shell), task_runners);
 }
 
-TEST_F(PlatformConfigurationTest, CallingRenderOutOfScopeIsIgnored) {
+TEST_F(PlatformConfigurationTest, OutOfScopeRenderCallsAreIgnored) {
   Settings settings = CreateSettingsForFixture();
   TaskRunners task_runners = GetTaskRunnersForFixture();
 
@@ -453,25 +453,57 @@ TEST_F(PlatformConfigurationTest, CallingRenderOutOfScopeIsIgnored) {
       std::make_shared<MockPlatformMessageHandler>();
   EXPECT_CALL(client, GetPlatformMessageHandler())
       .WillOnce(Return(platform_message_handler));
+  // Render should not be called.
   EXPECT_CALL(client, Render(_, _)).Times(Exactly(0));
 
   auto context = std::make_unique<MockRuntimeControllerContext>(
       settings, task_runners, client);
 
+  auto configuration = RunConfiguration::InferFromSettings(settings);
+  configuration.SetEntrypoint("incorrectImmediateRender");
+  ViewportMetrics implicit_view_metrics(
+      /*device_pixel_ratio=*/1.0, /*width=*/20, /*height=*/20,
+      /*physical_touch_slop=*/2, /*display_id=*/0);
+  context->LaunchRootIsolate(configuration, implicit_view_metrics);
+
+  // Wait for the Dart main function to end.
   fml::AutoResetWaitableEvent latch;
-  AddNativeCallback("NotifyNative", CREATE_NATIVE_ENTRY([&latch](auto args) {
-                      latch.Signal();
-                    }));
+  PostSync(task_runners.GetUITaskRunner(), [&]() { latch.Signal(); });
+  latch.Wait();
+
+  PostSync(task_runners.GetUITaskRunner(), [&]() { context.reset(); });
+}
+
+TEST_F(PlatformConfigurationTest, DuplicateRenderCallsAreIgnored) {
+  Settings settings = CreateSettingsForFixture();
+  TaskRunners task_runners = GetTaskRunnersForFixture();
+
+  MockRuntimeDelegate client;
+  auto platform_message_handler =
+      std::make_shared<MockPlatformMessageHandler>();
+  EXPECT_CALL(client, GetPlatformMessageHandler())
+      .WillOnce(Return(platform_message_handler));
+  // Render should only be called once, because the second call is ignored.
+  EXPECT_CALL(client, Render(_, _)).Times(Exactly(1));
+
+  auto context = std::make_unique<MockRuntimeControllerContext>(
+      settings, task_runners, client);
 
   auto configuration = RunConfiguration::InferFromSettings(settings);
-  configuration.SetEntrypoint("incorrectImmediateRender");
+  configuration.SetEntrypoint("incorrectDoubleRender");
   ViewportMetrics implicit_view_metrics(
       /*device_pixel_ratio=*/1.0, /*width=*/20, /*height=*/20,
       /*physical_touch_slop=*/2, /*display_id=*/0);
   context->LaunchRootIsolate(configuration, implicit_view_metrics);
 
+  // Wait for the Dart main function to end, which means the callbacks have been
+  // registered.
+  fml::AutoResetWaitableEvent latch;
+  PostSync(task_runners.GetUITaskRunner(), [&]() { latch.Signal(); });
   latch.Wait();
 
+  context->GetController().BeginFrame(fml::TimePoint::Now(), 0);
+
   PostSync(task_runners.GetUITaskRunner(), [&]() { context.reset(); });
 }