Follow jsc on not throwing when trying to add a property to a non-extensible object.

src/objects.cc

Index: src/objects.cc
===================================================================
--- src/objects.cc	(revision 7276)
+++ src/objects.cc	(working copy)
@@ -1438,13 +1438,19 @@
 
 MaybeObject* JSObject::AddProperty(String* name,
                                    Object* value,
-                                   PropertyAttributes attributes) {
+                                   PropertyAttributes attributes,
+                                   StrictModeFlag strict_mode) {
   ASSERT(!IsJSGlobalProxy());
   Heap* heap = GetHeap();
   if (!map()->is_extensible()) {
-    Handle<Object> args[1] = {Handle<String>(name)};
-    return heap->isolate()->Throw(
-        *FACTORY->NewTypeError("object_not_extensible", HandleVector(args, 1)));
+    if (strict_mode == kNonStrictMode) {
+      return heap->undefined_value();
+    } else {
+      Handle<Object> args[1] = {Handle<String>(name)};
+      return heap->isolate()->Throw(
+          *FACTORY->NewTypeError("object_not_extensible",
+                                 HandleVector(args, 1)));
+    }
   }
   if (HasFastProperties()) {
     // Ensure the descriptor array does not get too big.
@@ -1485,7 +1491,7 @@
     return SetProperty(&result, name, value, attributes, strict_mode);
   }
   // Add a new real property.
-  return AddProperty(name, value, attributes);
+  return AddProperty(name, value, attributes, strict_mode);
 }
 
 
@@ -1989,7 +1995,7 @@
   }
   if (!result->IsFound()) {
     // Neither properties nor transitions found.
-    return AddProperty(name, value, attributes);
+    return AddProperty(name, value, attributes, strict_mode);
   }
   if (result->IsReadOnly() && result->IsProperty()) {
     if (strict_mode == kStrictMode) {
@@ -2096,7 +2102,7 @@
   // Check for accessor in prototype chain removed here in clone.
   if (!result.IsFound()) {
     // Neither properties nor transitions found.
-    return AddProperty(name, value, attributes);
+    return AddProperty(name, value, attributes, kNonStrictMode);
   }
 
   PropertyDetails details = PropertyDetails(attributes, NORMAL);
@@ -7347,13 +7353,17 @@
         // When we set the is_extensible flag to false we always force
         // the element into dictionary mode (and force them to stay there).
         if (!map()->is_extensible()) {
-          Handle<Object> number(isolate->factory()->NewNumberFromUint(index));
-          Handle<String> index_string(
-              isolate->factory()->NumberToString(number));
-          Handle<Object> args[1] = { index_string };
-          return isolate->Throw(
-              *isolate->factory()->NewTypeError("object_not_extensible",
-                                                HandleVector(args, 1)));
+          if (strict_mode == kNonStrictMode) {
+            return isolate->heap()->undefined_value();
+          } else {
+            Handle<Object> number(isolate->factory()->NewNumberFromUint(index));
+            Handle<String> index_string(
+                isolate->factory()->NumberToString(number));
+            Handle<Object> args[1] = { index_string };
+            return isolate->Throw(
+                *isolate->factory()->NewTypeError("object_not_extensible",
+                                                  HandleVector(args, 1)));
+          }
         }
         Object* result;
         { MaybeObject* maybe_result = dictionary->AtNumberPut(index, value);