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

[Rico, 2011/01/05 13:40:39]

period at end of comment

[Peter Hallam, 2011/01/05 23:50:31]

Done.

 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
+// the non configurable property.

[Rico, 2011/01/05 13:40:39]

a the -> a

[Peter Hallam, 2011/01/05 23:50:31]

Done.

+try {
+  var descAccessor = { get: function() { return 0; } };

[Rico, 2011/01/05 13:37:01]

could we also try with descElementNonWritable, which should also throw

[Peter Hallam, 2011/01/05 23:50:31]

I've added a test for descElementNonWritable. Interestingly enough it does not
throw. I confirmed with a thread on es-discuss.

On 2011/01/05 13:37:01, Rico wrote:

+  Object.defineProperty(obj6, '2', descAccessor);
   assertUnreachable();
 } catch (e) {
   assertTrue(/Cannot redefine property/.test(e));
 }
 
 Object.defineProperty(obj6, '3', descElementNonWritable);
 desc = Object.getOwnPropertyDescriptor(obj6, '3');
 assertEquals(desc.value, 'foofoo');
 assertFalse(desc.writable);
 assertTrue(desc.enumerable);
@@ skipping 55 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

[Rico, 2011/01/05 13:40:39]

period at end of comment

[Peter Hallam, 2011/01/05 23:50:31]

Done.

 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; } };

[Rico, 2011/01/05 13:37:01]

Again, could we also try with descElementNonWritable and descNonEnumerable which
should both throw

[Peter Hallam, 2011/01/05 23:50:31]

Done. See comment above.

+  Object.defineProperty(arr, '2', descAccessor);
   assertUnreachable();
 } catch (e) {
   assertTrue(/Cannot redefine property/.test(e));
 }
 
 Object.defineProperty(arr, '3', descElementNonWritable);
 desc = Object.getOwnPropertyDescriptor(arr, '3');
 assertEquals(desc.value, 'foofoo');
 assertFalse(desc.writable);
 assertTrue(desc.enumerable);
@@ skipping 48 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);