Allow microtasks to throw exceptions and handle them gracefully

test/cctest/test-api.cc

 // Copyright 2012 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 20742 matching lines @@
   CompileRun("1+1;");
   CHECK_EQ(2, CompileRun("ext1Calls")->Int32Value());
   CHECK_EQ(2, CompileRun("ext2Calls")->Int32Value());
 
   CompileRun("1+1;");
   CHECK_EQ(2, CompileRun("ext1Calls")->Int32Value());
   CHECK_EQ(2, CompileRun("ext2Calls")->Int32Value());
 }
 
 
+static void MicrotaskExceptionOne(
+    const v8::FunctionCallbackInfo<Value>& info) {
+  v8::HandleScope scope(info.GetIsolate());
+  CompileRun("exception1Calls++;");
+  info.GetIsolate()->ThrowException(
+      v8::Exception::Error(v8_str("first")));
+}
+
+
+static void MicrotaskExceptionTwo(
+    const v8::FunctionCallbackInfo<Value>& info) {
+  v8::HandleScope scope(info.GetIsolate());
+  CompileRun("exception2Calls++;");
+  info.GetIsolate()->ThrowException(
+      v8::Exception::Error(v8_str("second")));
+}
+
+
+TEST(RunMicrotasksIgnoresThrownExceptions) {
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope scope(isolate);
+  CompileRun(
+      "var exception1Calls = 0;"
+      "var exception2Calls = 0;");
+  isolate->EnqueueMicrotask(
+      Function::New(isolate, MicrotaskExceptionOne));
+  isolate->EnqueueMicrotask(
+      Function::New(isolate, MicrotaskExceptionTwo));
+  TryCatch try_catch;
+  CompileRun("1+1;");
+  CHECK(!try_catch.HasCaught());
+  CHECK_EQ(1, CompileRun("exception1Calls")->Int32Value());
+  CHECK_EQ(1, CompileRun("exception2Calls")->Int32Value());
+}
+
+
 TEST(SetAutorunMicrotasks) {
   LocalContext env;
   v8::HandleScope scope(env->GetIsolate());
   CompileRun(
       "var ext1Calls = 0;"
       "var ext2Calls = 0;");
   CompileRun("1+1;");
   CHECK_EQ(0, CompileRun("ext1Calls")->Int32Value());
   CHECK_EQ(0, CompileRun("ext2Calls")->Int32Value());
 
@@ skipping 1853 matching lines @@
   Local<Script> script = v8::ScriptCompiler::Compile(
       isolate, &script_source);
   Local<Value> script_name = script->GetUnboundScript()->GetScriptName();
   CHECK(!script_name.IsEmpty());
   CHECK(script_name->IsString());
   String::Utf8Value utf8_name(script_name);
   CHECK_EQ(url, *utf8_name);
   int line_number = script->GetUnboundScript()->GetLineNumber(0);
   CHECK_EQ(13, line_number);
 }