[api] Throw in defineProperty() when necessary.

src/objects.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <memory>
 #include <sstream>
@@ skipping 1667 matching lines @@
 }
 
 Maybe<bool> DefinePropertyWithInterceptorInternal(
     LookupIterator* it, Handle<InterceptorInfo> interceptor,
     Object::ShouldThrow should_throw, PropertyDescriptor& desc) {
   Isolate* isolate = it->isolate();
   // Make sure that the top context does not change when doing callbacks or
   // interceptor calls.
   AssertNoContextChange ncc(isolate);
 
+  // Throw if setter callback is defined and define property is called with a

[jochen (gone - plz use gerrit), 2016/09/14 08:43:01]

how about only doing this if we don't have a definer?

[Franzi, 2016/09/14 16:19:51]

If I understand the IDL specification correctly, we're supposed to throw before
we call 
OrdinaryDefineOwnProperty(), in which we check for a definer. Or is that just an
implementation detail
and the definer should intercept before anything else happens? 

+  // non data descriptor.
+  if (!interceptor->setter()->IsUndefined(isolate) &&
+      !PropertyDescriptor::IsDataDescriptor(&desc)) {
+    isolate->Throw(*isolate->factory()->NewTypeError(
+        MessageTemplate::kDefineDisallowedWithNonDataDescriptor,
+        it->GetName()));
+    return Nothing<bool>();
+  }
   if (interceptor->definer()->IsUndefined(isolate)) return Just(false);
 
   Handle<JSObject> holder = it->GetHolder<JSObject>();
   bool result;
   Handle<Object> receiver = it->GetReceiver();
   if (!receiver->IsJSReceiver()) {
     ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, receiver,
                                      Object::ConvertReceiver(isolate, receiver),
                                      Nothing<bool>());
   }
@@ skipping 17790 matching lines @@
 Handle<Object> JSModule::LoadExport(Handle<JSModule> module,
                                     Handle<String> name) {
   Isolate* isolate = module->GetIsolate();
   LookupIterator it(module, name);
   Handle<Cell> cell = Handle<Cell>::cast(JSObject::GetDataProperty(&it));
   return handle(cell->value(), isolate);
 }
 
 }  // namespace internal
 }  // namespace v8