[es6] Make sure we call add property when adding a new property

src/objects.cc

 // Copyright 2013 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 <iomanip>
 #include <sstream>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
@@ skipping 3315 matching lines @@
       UNREACHABLE();
       break;
 
     case LookupIterator::INTERCEPTOR:
     case LookupIterator::JSPROXY:
     case LookupIterator::ACCESS_CHECK: {
       bool found = false;
       MaybeHandle<Object> result = SetPropertyInternal(
           &own_lookup, value, language_mode, store_mode, &found);
       if (found) return result;
-      return SetDataProperty(&own_lookup, value);
+      return AddDataProperty(&own_lookup, value, NONE, language_mode,

[arv (Not doing code reviews), 2015/06/01 14:17:58]

AddDataProperty has a DCHECK that the receiver is not a proxy.

Can found be false afte a proxy trap is invoked?

[caitp (gmail), 2015/06/01 14:36:38]

In the current implementation, found can be false if the property key is a
Symbol (the proxy trap is never invoked in this case).

[Toon Verwaest, 2015/06/01 14:37:03]

Not if the receiver is the proxy, as is the case here.

[Toon Verwaest, 2015/06/01 14:41:29]

I think you'd want to make this switch nested in a for-loop like is the case for
other Set with iterator. After ruling out the interceptor / access check, you
just continue with whatever is behind the interceptor / access check. Behind the
access check could be an interceptor. Behind the interceptor could be data, or
not-found.

+                             store_mode);
     }
   }
 
   UNREACHABLE();
   return MaybeHandle<Object>();
 }
 
 
 MaybeHandle<Object> Object::WriteToReadOnlyProperty(
     LookupIterator* it, Handle<Object> value, LanguageMode language_mode) {
@@ skipping 14017 matching lines @@
 void PropertyCell::SetValueWithInvalidation(Handle<PropertyCell> cell,
                                             Handle<Object> new_value) {
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 } }  // namespace v8::internal