Throw when a holey property is set in Array.sort

src/objects.cc

 // Copyright 2015 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <memory>
 #include <sstream>
@@ skipping 16862 matching lines @@
 }
 
 
 // Collects all defined (non-hole) and non-undefined (array) elements at
 // the start of the elements array.
 // If the object is in dictionary mode, it is converted to fast elements
 // mode.
 Handle<Object> JSObject::PrepareElementsForSort(Handle<JSObject> object,
                                                 uint32_t limit) {
   Isolate* isolate = object->GetIsolate();
-  if (object->HasSloppyArgumentsElements()) {
+  if (object->HasSloppyArgumentsElements() || !object->map()->is_extensible()) {
     return handle(Smi::FromInt(-1), isolate);
   }
 
   if (object->HasStringWrapperElements()) {
     int len = String::cast(Handle<JSValue>::cast(object)->value())->length();
     return handle(Smi::FromInt(len), isolate);
   }
 
   if (object->HasDictionaryElements()) {
     // Convert to fast elements containing only the existing properties.
@@ skipping 3131 matching lines @@
       // depend on this.
       return DICTIONARY_ELEMENTS;
     }
     DCHECK_LE(kind, LAST_ELEMENTS_KIND);
     return kind;
   }
 }
 
 }  // namespace internal
 }  // namespace v8