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

src/runtime.cc

Index: src/runtime.cc
===================================================================
--- src/runtime.cc	(revision 8272)
+++ src/runtime.cc	(working copy)
@@ -3995,6 +3995,24 @@
       return *value;
     }
 
+    // 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.
+    if (((attr & (DONT_DELETE | DONT_ENUM | READ_ONLY)) != 0)) {
+      // 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;
+    }
+
     Handle<Object> result = SetElement(js_object, index, value, strict_mode);
     if (result.is_null()) return Failure::Exception();
     return *value;
@@ -4003,6 +4021,23 @@
   if (key->IsString()) {
     Handle<Object> result;
     if (Handle<String>::cast(key)->AsArrayIndex(&index)) {

[Erik Corry, 2011/06/14 13:21:51]

There's a ton of copied code here.
You could create a helper or just recurse:  return SetObjectProperty(isolate,
object, Smi::fromInt(index), value, attr, strict_mode);

[Rico, 2011/06/14 13:44:23]

Done.

+      // 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.
+      if (((attr & (DONT_DELETE | DONT_ENUM | READ_ONLY)) != 0)) {
+        // 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;
+      }
       result = SetElement(js_object, index, value, strict_mode);
     } else {
       Handle<String> key_string = Handle<String>::cast(key);