Correctly set ReadOnly flag on indexed properties when using the API Set method (fixes issue 1470)

src/runtime.cc

 // Copyright 2011 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 3917 matching lines @@
   }
 
   return Runtime::ForceSetObjectProperty(isolate,
                                          js_object,
                                          name,
                                          obj_value,
                                          attr);
 }
 
 
+// Special case for elements if any of the flags are true.
+// If elements are in fast case we always implicitly assume that:
+// DONT_DELETE: false, DONT_ENUM: false, READ_ONLY: false.
+static MaybeObject* NormalizeObjectSetElement(Isolate* isolate,
+                                              Handle<JSObject> js_object,
+                                              uint32_t index,
+                                              Handle<Object> value,
+                                              PropertyAttributes attr) {
+  // Normalize the elements to enable attributes on the property.
+  NormalizeElements(js_object);
+  Handle<NumberDictionary> dictionary(js_object->element_dictionary());
+  // Make sure that we never go back to fast case.
+  dictionary->set_requires_slow_elements();
+  PropertyDetails details = PropertyDetails(attr, NORMAL);
+  Handle<NumberDictionary> extended_dictionary =
+      NumberDictionarySet(dictionary, index, value, details);
+  if (*extended_dictionary != *dictionary) {
+    js_object->set_elements(*extended_dictionary);
+  }
+  return *value;
+}
+
+
 MaybeObject* Runtime::SetObjectProperty(Isolate* isolate,
                                         Handle<Object> object,
                                         Handle<Object> key,
                                         Handle<Object> value,
                                         PropertyAttributes attr,
                                         StrictModeFlag strict_mode) {
   HandleScope scope(isolate);
 
   if (object->IsUndefined() || object->IsNull()) {
     Handle<Object> args[2] = { key, object };
@@ skipping 15 matching lines @@
     // of a string using [] notation.  We need to support this too in
     // JavaScript.
     // In the case of a String object we just need to redirect the assignment to
     // the underlying string if the index is in range.  Since the underlying
     // string does nothing with the assignment then we can ignore such
     // assignments.
     if (js_object->IsStringObjectWithCharacterAt(index)) {
       return *value;
     }
 
+    if (((attr & (DONT_DELETE | DONT_ENUM | READ_ONLY)) != 0)) {
+      return NormalizeObjectSetElement(isolate, js_object, index, value, attr);
+    }
+
     Handle<Object> result = SetElement(js_object, index, value, strict_mode);
     if (result.is_null()) return Failure::Exception();
     return *value;
   }
 
   if (key->IsString()) {
     Handle<Object> result;
     if (Handle<String>::cast(key)->AsArrayIndex(&index)) {
+      if (((attr & (DONT_DELETE | DONT_ENUM | READ_ONLY)) != 0)) {
+        return NormalizeObjectSetElement(isolate,
+                                         js_object,
+                                         index,
+                                         value,
+                                         attr);
+      }
       result = SetElement(js_object, index, value, strict_mode);
     } else {
       Handle<String> key_string = Handle<String>::cast(key);
       key_string->TryFlatten();
       result = SetProperty(js_object, key_string, value, attr, strict_mode);
     }
     if (result.is_null()) return Failure::Exception();
     return *value;
   }
 
@@ skipping 8349 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal