src: use correct outer Context’s microtask queue

common.gypi

@@ -36,7 +36,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.20',
+    'v8_embedder_string': '-node.21',
 
     ##### V8 defaults for Node.js #####
 

deps/v8/include/v8.h

@@ -10417,9 +10417,12 @@ class V8_EXPORT Context {
    */
   void Exit();
 
-  /** Returns an isolate associated with a current context. */
+  /** Returns the isolate associated with a current context. */
   Isolate* GetIsolate();
 
+  /** Returns the microtask queue associated with a current context. */
+  MicrotaskQueue* GetMicrotaskQueue();
+
   /**
    * The field at kDebugIdIndex used to be reserved for the inspector.
    * It now serves no purpose.

deps/v8/src/api/api.cc

@@ -6118,6 +6118,12 @@ v8::Isolate* Context::GetIsolate() {
   return reinterpret_cast<Isolate*>(env->GetIsolate());
 }
 
+v8::MicrotaskQueue* Context::GetMicrotaskQueue() {
+  i::Handle<i::Context> env = Utils::OpenHandle(this);
+  CHECK(env->IsNativeContext());
+  return i::Handle<i::NativeContext>::cast(env)->microtask_queue();
+}
+
 v8::Local<v8::Object> Context::Global() {
   i::Handle<i::Context> context = Utils::OpenHandle(this);
   i::Isolate* isolate = context->GetIsolate();

deps/v8/test/cctest/test-api.cc

@@ -28348,3 +28348,13 @@ TEST(TriggerThreadSafeMetricsEvent) {
   CHECK_EQ(recorder->count_, 1);  // Increased.
   CHECK_EQ(recorder->module_count_, 42);
 }
+
+THREADED_TEST(MicrotaskQueueOfContext) {
+  auto microtask_queue = v8::MicrotaskQueue::New(CcTest::isolate());
+  v8::HandleScope scope(CcTest::isolate());
+  v8::Local<Context> context = Context::New(
+      CcTest::isolate(), nullptr, v8::MaybeLocal<ObjectTemplate>(),
+      v8::MaybeLocal<Value>(), v8::DeserializeInternalFieldsCallback(),
+      microtask_queue.get());
+  CHECK_EQ(context->GetMicrotaskQueue(), microtask_queue.get());
+}

src/async_wrap.cc

@@ -827,7 +827,8 @@ void AsyncWrap::EmitDestroy(Environment* env, double async_id) {
   // interrupt to get this Microtask scheduled as fast as possible.
   if (env->destroy_async_id_list()->size() == 16384) {
     env->RequestInterrupt([](Environment* env) {
-      env->isolate()->EnqueueMicrotask(
+      env->context()->GetMicrotaskQueue()->EnqueueMicrotask(
+        env->isolate(),
         [](void* arg) {
           DestroyAsyncIdsCallback(static_cast<Environment*>(arg));
         }, env);

src/node_contextify.cc

@@ -199,7 +199,9 @@ MaybeLocal<Context> ContextifyContext::CreateV8Context(
       object_template,
       {},       // global object
       {},       // deserialization callback
-      microtask_queue() ? microtask_queue().get() : nullptr);
+      microtask_queue() ?
+          microtask_queue().get() :
+          env->isolate()->GetCurrentContext()->GetMicrotaskQueue());
   if (ctx.IsEmpty()) return MaybeLocal<Context>();
   // Only partially initialize the context - the primordials are left out
   // and only initialized when necessary.

src/node_task_queue.cc

@@ -96,7 +96,8 @@ static void EnqueueMicrotask(const FunctionCallbackInfo<Value>& args) {
 
   CHECK(args[0]->IsFunction());
 
-  isolate->EnqueueMicrotask(args[0].As<Function>());
+  isolate->GetCurrentContext()->GetMicrotaskQueue()
+      ->EnqueueMicrotask(isolate, args[0].As<Function>());
 }
 
 static void RunMicrotasks(const FunctionCallbackInfo<Value>& args) {

test/cctest/test_environment.cc

@@ -608,3 +608,58 @@ TEST_F(NodeZeroIsolateTestFixture, CtrlCWithOnlySafeTerminationTest) {
   isolate->Dispose();
 }
 #endif  // _WIN32
+
+TEST_F(EnvironmentTest, NestedMicrotaskQueue) {
+  const v8::HandleScope handle_scope(isolate_);
+  const Argv argv;
+
+  std::unique_ptr<v8::MicrotaskQueue> queue = v8::MicrotaskQueue::New(isolate_);
+  v8::Local<v8::Context> context = v8::Context::New(
+      isolate_, nullptr, {}, {}, {}, queue.get());
+  node::InitializeContext(context);
+  v8::Context::Scope context_scope(context);
+
+  int callback_calls = 0;
+  v8::Local<v8::Function> must_call = v8::Function::New(
+      context,
+      [](const v8::FunctionCallbackInfo<v8::Value>& info) {
+        int* callback_calls =
+            static_cast<int*>(info.Data().As<v8::External>()->Value());
+        *callback_calls |= info[0].As<v8::Int32>()->Value();
+      },
+      v8::External::New(isolate_, static_cast<void*>(&callback_calls)))
+          .ToLocalChecked();
+  context->Global()->Set(
+      context,
+      v8::String::NewFromUtf8Literal(isolate_, "mustCall"),
+      must_call).Check();
+
+  node::IsolateData* isolate_data = node::CreateIsolateData(
+      isolate_, &NodeTestFixture::current_loop, platform.get());
+  CHECK_NE(nullptr, isolate_data);
+
+  node::Environment* env = node::CreateEnvironment(
+      isolate_data, context, {}, {});
+  CHECK_NE(nullptr, env);
+
+  node::LoadEnvironment(
+      env,
+      "Promise.resolve().then(() => mustCall(1 << 0));\n"
+      "require('vm').runInNewContext("
+      "    'Promise.resolve().then(() => mustCall(1 << 1))',"
+      "    { mustCall },"
+      "    { microtaskMode: 'afterEvaluate' }"
+      ");"
+      "require('vm').runInNewContext("
+      "    'Promise.resolve().then(() => mustCall(1 << 2))',"
+      "    { mustCall }"
+      ");").ToLocalChecked();
+  EXPECT_EQ(callback_calls, 1 << 1);
+  isolate_->PerformMicrotaskCheckpoint();
+  EXPECT_EQ(callback_calls, 1 << 1);
+  queue->PerformCheckpoint(isolate_);
+  EXPECT_EQ(callback_calls, (1 << 0) | (1 << 1) | (1 << 2));
+
+  node::FreeEnvironment(env);
+  node::FreeIsolateData(isolate_data);
+}