Allow microtasks to throw exceptions and handle them gracefully

test/cctest/test-thread-termination.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 340 matching lines @@
   v8::Handle<v8::ObjectTemplate> global = CreateGlobalTemplate(
       isolate, TerminateCurrentThread, DoLoopCancelTerminate);
   v8::Handle<v8::Context> context = v8::Context::New(isolate, NULL, global);
   v8::Context::Scope context_scope(context);
   CHECK(!v8::V8::IsExecutionTerminating(CcTest::isolate()));
   v8::Handle<v8::String> source = v8::String::NewFromUtf8(
       isolate, "try { doloop(); } catch(e) { fail(); } 'completed';");
   // Check that execution completed with correct return value.
   CHECK(v8::Script::Compile(source)->Run()->Equals(v8_str("completed")));
 }
+
+
+void MicrotaskShouldNotRun(const v8::FunctionCallbackInfo<v8::Value>& info) {
+  CHECK(false);
+}
+
+
+void MicrotaskLoopForever(const v8::FunctionCallbackInfo<v8::Value>& info) {
+  v8::Isolate* isolate = info.GetIsolate();
+  v8::HandleScope scope(isolate);
+  // Enqueue another should-not-run task to ensure we clean out the queue
+  // when we terminate.
+  isolate->EnqueueMicrotask(v8::Function::New(isolate, MicrotaskShouldNotRun));
+  CompileRun("terminate(); while (true) { }");
+  CHECK(v8::V8::IsExecutionTerminating());
+}
+
+
+TEST(TerminateFromOtherThreadWhileMicrotaskRunning) {
+  semaphore = new v8::internal::Semaphore(0);
+  TerminatorThread thread(CcTest::i_isolate());
+  thread.Start();
+
+  v8::Isolate* isolate = CcTest::isolate();
+  isolate->SetAutorunMicrotasks(false);
+  v8::HandleScope scope(isolate);
+  v8::Handle<v8::ObjectTemplate> global =
+      CreateGlobalTemplate(CcTest::isolate(), Signal, DoLoop);
+  v8::Handle<v8::Context> context =
+      v8::Context::New(CcTest::isolate(), NULL, global);
+  v8::Context::Scope context_scope(context);
+  isolate->EnqueueMicrotask(v8::Function::New(isolate, MicrotaskLoopForever));
+  // The second task should never be run because we bail out if we're
+  // terminating.
+  isolate->EnqueueMicrotask(v8::Function::New(isolate, MicrotaskShouldNotRun));
+  isolate->RunMicrotasks();
+
+  v8::V8::CancelTerminateExecution(isolate);
+  isolate->RunMicrotasks();  // should not run MicrotaskShouldNotRun
+
+  thread.Join();
+  delete semaphore;
+  semaphore = NULL;
+}