Fix evaluation order problems in Object.observe hooks.

src/objects.cc

 // Copyright 2013 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 3260 matching lines @@
 
   Handle<Object> hresult;
   if (!result->ToHandle(&hresult, isolate)) return result;
 
   if (FLAG_harmony_observation && map()->is_observed()) {
     if (lookup->IsTransition()) {
       EnqueueChangeRecord(self, "new", name, old_value);
     } else {
       LookupResult new_lookup(isolate);
       self->LocalLookup(*name, &new_lookup, true);
-      if (new_lookup.IsDataProperty() &&
-          !Object::GetProperty(self, name)->SameValue(*old_value)) {
-        EnqueueChangeRecord(self, "updated", name, old_value);
+      if (new_lookup.IsDataProperty()) {
+        Handle<Object> new_value = Object::GetProperty(self, name);
+        if (!new_value->SameValue(*old_value)) {
+          EnqueueChangeRecord(self, "updated", name, old_value);
+        }
       }
     }
   }
 
   return *hresult;
 }
 
 
 // Set a real local property, even if it is READ_ONLY.  If the property is not
 // present, add it with attributes NONE.  This code is an exact clone of
@@ skipping 129 matching lines @@
   if (!result->ToHandle(&hresult, isolate)) return result;
 
   if (is_observed) {
     if (lookup.IsTransition()) {
       EnqueueChangeRecord(self, "new", name, old_value);
     } else if (old_value->IsTheHole()) {
       EnqueueChangeRecord(self, "reconfigured", name, old_value);
     } else {
       LookupResult new_lookup(isolate);
       self->LocalLookup(*name, &new_lookup, true);
-      bool value_changed = new_lookup.IsDataProperty() &&
-          !old_value->SameValue(*Object::GetProperty(self, name));
+      bool value_changed = false;
+      if (new_lookup.IsDataProperty()) {
+        Handle<Object> new_value = Object::GetProperty(self, name);
+        value_changed = !old_value->SameValue(*new_value);
+      }
       if (new_lookup.GetAttributes() != old_attributes) {
         if (!value_changed) old_value = isolate->factory()->the_hole_value();
         EnqueueChangeRecord(self, "reconfigured", name, old_value);
       } else if (value_changed) {
         EnqueueChangeRecord(self, "updated", name, old_value);
       }
     }
   }
 
   return *hresult;
@@ skipping 7522 matching lines @@
   if (old_attributes == ABSENT) {
     EnqueueChangeRecord(self, "new", name, old_value);
     if (self->IsJSArray() &&
         !old_length->SameValue(Handle<JSArray>::cast(self)->length())) {
       EnqueueChangeRecord(
           self, "updated", isolate->factory()->length_string(), old_length);
     }
   } else if (old_value->IsTheHole()) {
     EnqueueChangeRecord(self, "reconfigured", name, old_value);
   } else {
-    bool value_changed =
-        !old_value->SameValue(*Object::GetElement(self, index));
+    Handle<Object> new_value = Object::GetElement(self, index);
+    bool value_changed = !old_value->SameValue(*new_value);
     if (old_attributes != new_attributes) {
       if (!value_changed) old_value = isolate->factory()->the_hole_value();
       EnqueueChangeRecord(self, "reconfigured", name, old_value);
     } else if (value_changed) {
       EnqueueChangeRecord(self, "updated", name, old_value);
     }
   }
 
   return *hresult;
 }
@@ skipping 3540 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal