First cut at bug 992

test/mjsunit/object-define-property.js

 // Copyright 2010 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 731 matching lines @@
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
 Object.defineProperty(obj6, '2', descElementNonConfigurable);
 desc = Object.getOwnPropertyDescriptor(obj6, '2');
 assertEquals(desc.value, 'barfoo');
 assertTrue(desc.writable);
 assertTrue(desc.enumerable);
 assertFalse(desc.configurable);
 
-// Ensure that we can't overwrite the non configurable element.
+// Can use defineProperty to change the value of a non
+// configurable property.
 try {
   Object.defineProperty(obj6, '2', descElement);
+  desc = Object.getOwnPropertyDescriptor(obj6, '2');
+  assertEquals(desc.value, 'foobar');
+} catch (e) {
+  assertUnreachable();
+}
+
+// Ensure that we can't change the descriptor of a
+// non configurable property.
+try {
+  var descAccessor = { get: function() { return 0; } };
+  Object.defineProperty(obj6, '2', descAccessor);
   assertUnreachable();
 } catch (e) {
   assertTrue(/Cannot redefine property/.test(e));
 }
 
+Object.defineProperty(obj6, '2', descElementNonWritable);
+desc = Object.getOwnPropertyDescriptor(obj6, '2');
+assertEquals(desc.value, 'foofoo');
+assertFalse(desc.writable);
+assertTrue(desc.enumerable);
+assertFalse(desc.configurable);
+
 Object.defineProperty(obj6, '3', descElementNonWritable);
 desc = Object.getOwnPropertyDescriptor(obj6, '3');
 assertEquals(desc.value, 'foofoo');
 assertFalse(desc.writable);
 assertTrue(desc.enumerable);
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
 Object.defineProperty(obj6, '4', descElementNonEnumerable);
 desc = Object.getOwnPropertyDescriptor(obj6, '4');
@@ skipping 50 matching lines @@
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
 Object.defineProperty(arr, '2', descElementNonConfigurable);
 desc = Object.getOwnPropertyDescriptor(arr, '2');
 assertEquals(desc.value, 'barfoo');
 assertTrue(desc.writable);
 assertTrue(desc.enumerable);
 assertFalse(desc.configurable);
 
-// Ensure that we can't overwrite the non configurable element.
+// Can use defineProperty to change the value of a non
+// configurable property of an array.
 try {
   Object.defineProperty(arr, '2', descElement);
+  desc = Object.getOwnPropertyDescriptor(arr, '2');
+  assertEquals(desc.value, 'foobar');
+} catch (e) {
+  assertUnreachable();
+}
+
+// Ensure that we can't change the descriptor of a
+// non configurable property.
+try {
+  var descAccessor = { get: function() { return 0; } };
+  Object.defineProperty(arr, '2', descAccessor);
   assertUnreachable();
 } catch (e) {
   assertTrue(/Cannot redefine property/.test(e));
 }
 
+Object.defineProperty(arr, '2', descElementNonWritable);
+desc = Object.getOwnPropertyDescriptor(arr, '2');
+assertEquals(desc.value, 'foofoo');
+assertFalse(desc.writable);
+assertTrue(desc.enumerable);
+assertFalse(desc.configurable);
+
 Object.defineProperty(arr, '3', descElementNonWritable);
 desc = Object.getOwnPropertyDescriptor(arr, '3');
 assertEquals(desc.value, 'foofoo');
 assertFalse(desc.writable);
 assertTrue(desc.enumerable);
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
 Object.defineProperty(arr, '4', descElementNonEnumerable);
 desc = Object.getOwnPropertyDescriptor(arr, '4');
@@ skipping 43 matching lines @@
 assertEquals(undefined, o.x);
 o.x = 37;
 assertEquals(undefined, o.x);
 
 // Ignore inherited properties.
 o = { __proto__ : { x : 87 } };
 Object.defineProperty(o, "x", { writable: false });
 assertEquals(undefined, o.x);
 o.x = 37;
 assertEquals(undefined, o.x);