[api] Throw in defineProperty() when necessary.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 0f6ce61c06f0bd58af6bae4d9887c3cf8b1ac6c1..fd8843da16cb6e40ff8ccd7c23746b1c6147e7b2 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -1685,6 +1685,15 @@ Maybe<bool> DefinePropertyWithInterceptorInternal(
   // 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>();