Make name and message non-enumerable on Error object (this is a partial fix for issue 1215)

test/mjsunit/error-constructors.js

 // 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 41 matching lines @@
 // dont-delete. This is not specified, but allowing overwriting the
 // name property with a getter can leaks error objects from different
 // script tags in the same context in a browser setting. We therefore
 // disallow changes to the name property on error objects.
 assertEquals("ReferenceError", ReferenceError.prototype.name);
 delete ReferenceError.prototype.name;
 assertEquals("ReferenceError", ReferenceError.prototype.name);
 ReferenceError.prototype.name = "not a reference error";
 assertEquals("ReferenceError", ReferenceError.prototype.name);
 
+// Check that message and name are not enumerable on Error objects.
+var desc = Object.getOwnPropertyDescriptor(Error.prototype, 'name');
+assertFalse(desc['enumerable']);
+desc = Object.getOwnPropertyDescriptor(Error.prototype, 'message');
+assertFalse(desc['enumerable']);
+
+var e = new Error("foobar");
+desc = Object.getOwnPropertyDescriptor(e, 'message');
+assertFalse(desc['enumerable']);
+desc = Object.getOwnPropertyDescriptor(e, 'arguments');
+assertFalse(desc['enumerable']);
+desc = Object.getOwnPropertyDescriptor(e, 'type');
+assertFalse(desc['enumerable']);
+desc = Object.getOwnPropertyDescriptor(e, 'stack');
+assertFalse(desc['enumerable']);
+
+// Name is not an own property, test that it is not enumerable by running
+// through all properties of e.
+for (var v in e) {

[Mads Ager (chromium), 2011/06/15 13:41:54]

Error objects should have no enumerable properties at this point, right? So you
could even assertUnreachable unconditionally in the body. Maybe some of the code
above prevents that? In that case, move this up so you can do it?

[Rico, 2011/06/15 13:54:33]

Done, but I kept the assertions above (to guarantee that the properties are
actually there)

+  if (v == 'name') assertUnreachable();
+}