Fix Error object value lookups.

src/messages.cc

 // Copyright 2011 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/messages.h"
 
 #include "src/api.h"
 #include "src/execution.h"
 #include "src/isolate-inl.h"
 #include "src/string-builder.h"
@@ skipping 382 matching lines @@
   if (scope.has_visited()) return isolate->factory()->empty_string();
 
   Handle<String> name;
   Handle<String> message;
   Handle<Name> internal_key = isolate->factory()->internal_error_symbol();
   Handle<String> message_string =
       isolate->factory()->NewStringFromStaticChars("message");
   Handle<String> name_string = isolate->factory()->name_string();
   LookupIterator internal_error_lookup(
       error, internal_key, LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
-  LookupIterator message_lookup(
-      error, message_string, LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
-  LookupIterator name_lookup(error, name_string,
-                             LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
 
   // Find out whether an internally created error object is on the prototype
   // chain. If the name property is found on a holder prior to the internally
   // created error object, use that name property. Otherwise just use the
   // constructor name to avoid triggering possible side effects.
   // Similar for the message property. If the message property shadows the
   // internally created error object, use that message property. Otherwise
   // use empty string as message.
-  if (internal_error_lookup.IsFound()) {
-    if (!ShadowsInternalError(isolate, &name_lookup, &internal_error_lookup)) {
-      Handle<JSObject> holder = internal_error_lookup.GetHolder<JSObject>();
-      name = Handle<String>(holder->constructor_name());
-    }
-    if (!ShadowsInternalError(isolate, &message_lookup,
-                              &internal_error_lookup)) {
-      message = isolate->factory()->empty_string();
-    }
-  }
-  if (name.is_null()) {
+  LookupIterator name_lookup(error, name_string,
+                             LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
+  if (internal_error_lookup.IsFound() &&
+      !ShadowsInternalError(isolate, &name_lookup, &internal_error_lookup)) {
+    Handle<JSObject> holder = internal_error_lookup.GetHolder<JSObject>();
+    name = Handle<String>(holder->constructor_name());
+  } else {
     ASSIGN_RETURN_ON_EXCEPTION(
         isolate, name,
         GetStringifiedProperty(isolate, &name_lookup,
                                isolate->factory()->Error_string()),
         String);
   }
-  if (message.is_null()) {
+
+  LookupIterator message_lookup(
+      error, message_string, LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
+  if (internal_error_lookup.IsFound() &&
+      !ShadowsInternalError(isolate, &message_lookup, &internal_error_lookup)) {
+    message = isolate->factory()->empty_string();
+  } else {
     ASSIGN_RETURN_ON_EXCEPTION(
         isolate, message,
         GetStringifiedProperty(isolate, &message_lookup,
                                isolate->factory()->empty_string()),
         String);
   }
 
   if (name->length() == 0) return message;
   if (message->length() == 0) return name;
   IncrementalStringBuilder builder(isolate);
@@ skipping 30 matching lines @@
   if (obj->IsUndefined()) return default_value;
   if (!obj->IsString()) {
     ASSIGN_RETURN_ON_EXCEPTION(isolate, obj, Object::ToString(isolate, obj),
                                String);
   }
   return Handle<String>::cast(obj);
 }
 
 }  // namespace internal
 }  // namespace v8