Stop sending Object.observe notifications for API accessor properties

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 <sstream>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
@@ skipping 3979 matching lines @@
         UNREACHABLE();
 
       case LookupIterator::ACCESS_CHECK:
         if (!it.isolate()->MayNamedAccess(object, name, v8::ACCESS_SET)) {
           return SetPropertyWithFailedAccessCheck(&it, value, SLOPPY);
         }
         break;
 
       case LookupIterator::ACCESSOR: {
         PropertyDetails details = it.property_details();
-        Handle<Object> old_value = it.isolate()->factory()->the_hole_value();
         // Ensure the context isn't changed after calling into accessors.
         AssertNoContextChange ncc(it.isolate());
 
         Handle<Object> accessors = it.GetAccessors();
 
-        if (is_observed && accessors->IsAccessorInfo()) {
-          ASSIGN_RETURN_ON_EXCEPTION(
-              it.isolate(), old_value,
-              GetPropertyWithAccessor(it.GetReceiver(), it.name(),
-                                      it.GetHolder<JSObject>(), accessors),
-              Object);
-        }
-
         // Special handling for ExecutableAccessorInfo, which behaves like a
         // data property.
         if (handling == DONT_FORCE_FIELD &&
             accessors->IsExecutableAccessorInfo()) {
           Handle<Object> result;
           ASSIGN_RETURN_ON_EXCEPTION(
               it.isolate(), result,
               JSObject::SetPropertyWithAccessor(it.GetReceiver(), it.name(),
                                                 value, it.GetHolder<JSObject>(),
                                                 accessors, STRICT),
               Object);
           DCHECK(result->SameValue(*value));
 
           if (details.attributes() == attributes) {
-            // Regular property update if the attributes match.
-            if (is_observed && !old_value->SameValue(*value)) {
-              // If we are setting the prototype of a function and are
-              // observed, don't send change records because the prototype
-              // handles that itself.
-              if (!object->IsJSFunction() ||
-                  !Name::Equals(it.isolate()->factory()->prototype_string(),
-                                name) ||
-                  !Handle<JSFunction>::cast(object)->should_have_prototype()) {
-                RETURN_ON_EXCEPTION(
-                    it.isolate(),
-                    EnqueueChangeRecord(object, "update", name, old_value),
-                    Object);
-              }
-            }
             return value;
           }
 
           // Reconfigure the accessor if attributes mismatch.
           Handle<ExecutableAccessorInfo> new_data = Accessors::CloneAccessor(
               it.isolate(), Handle<ExecutableAccessorInfo>::cast(accessors));
           new_data->set_property_attributes(attributes);
           // By clearing the setter we don't have to introduce a lookup to
           // the setter, simply make it unavailable to reflect the
           // attributes.
           if (attributes & READ_ONLY) new_data->clear_setter();
           SetPropertyCallback(object, name, new_data, attributes);
           if (is_observed) {
-            if (old_value->SameValue(*value)) {
-              old_value = it.isolate()->factory()->the_hole_value();
-            }
             RETURN_ON_EXCEPTION(
                 it.isolate(),
-                EnqueueChangeRecord(object, "reconfigure", name, old_value),
+                EnqueueChangeRecord(object, "reconfigure", name,
+                                    it.isolate()->factory()->the_hole_value()),
                 Object);
           }
           return value;
         }
 
         it.ReconfigureDataProperty(value, attributes);
         it.PrepareForDataProperty(value);
         it.WriteDataValue(value);
 
         if (is_observed) {
-          if (old_value->SameValue(*value)) {
-            old_value = it.isolate()->factory()->the_hole_value();
-          }
           RETURN_ON_EXCEPTION(
               it.isolate(),
-              EnqueueChangeRecord(object, "reconfigure", name, old_value),
+              EnqueueChangeRecord(object, "reconfigure", name,
+                                  it.isolate()->factory()->the_hole_value()),
               Object);
         }
 
         return value;
       }
 
       case LookupIterator::DATA: {
         PropertyDetails details = it.property_details();
         Handle<Object> old_value = it.isolate()->factory()->the_hole_value();
         // Regular property update if the attributes match.
@@ skipping 12843 matching lines @@
   Handle<DependentCode> codes =
       DependentCode::Insert(handle(cell->dependent_code(), info->isolate()),
                             DependentCode::kPropertyCellChangedGroup,
                             info->object_wrapper());
   if (*codes != cell->dependent_code()) cell->set_dependent_code(*codes);
   info->dependencies(DependentCode::kPropertyCellChangedGroup)->Add(
       cell, info->zone());
 }
 
 } }  // namespace v8::internal