Make Object.freeze/seal/preventExtensions observable

test/mjsunit/harmony/object-observe.js

 // Copyright 2012 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 282 matching lines @@
 obj[''] = '';
 obj[''] = ' ';
 delete obj[''];
 Object.deliverChangeRecords(observer.callback);
 observer.assertCallbackRecords([
   { object: obj, type: 'new', name: '' },
   { object: obj, type: 'updated', name: '', oldValue: '' },
   { object: obj, type: 'deleted', name: '', oldValue: ' ' },
 ]);
 
+// Object.preventExtensions

[rossberg, 2013/10/30 19:11:45]

Cases you could add:

- invoking preventExtensions/seal/freeze on an object that already has
preventExtensions (should not create a preventExtensions change record)

- invoking seal/freeze on an object where not all properties can be
sealed/frozen (should still generate a preventExtensions change record, IIRC)

[rafaelw, 2013/10/30 23:00:30]

Good catch. Note that we now exit early from JSObject::PreventExtensions if the
map is already marked non-extensible.
I can't think of how to generate this case. How can this arise?

[rossberg, 2013/10/31 08:03:20]

Can you add a similar test for seal and freeze?
I'm sorry, you are right, it can't -- I keep forgetting that JavaScript has this
crank semantics where you can still change a data property from writable to
non-writable, even if it's allegedly non-configurable. 8/

[rafaelw, 2013/11/05 12:20:31]

Done.

+reset();
+var obj = { foo: 'bar'};
+Object.observe(obj, observer.callback);
+obj.baz = 'bat';
+Object.preventExtensions(obj);
+
+Object.deliverChangeRecords(observer.callback);
+observer.assertCallbackRecords([
+  { object: obj, type: 'new', name: 'baz' },
+  { object: obj, type: 'preventExtensions' },
+]);
+
+// Object.freeze
+reset();
+var obj = { a: 'a' };
+Object.defineProperty(obj, 'b', {
+  writable: false,
+  configurable: true,
+  value: 'b'
+});
+Object.defineProperty(obj, 'c', {
+  writable: true,
+  configurable: false,
+  value: 'c'
+});
+Object.defineProperty(obj, 'd', {
+  writable: false,
+  configurable: false,
+  value: 'd'
+});
+Object.observe(obj, observer.callback);
+Object.freeze(obj);
+
+Object.deliverChangeRecords(observer.callback);
+observer.assertCallbackRecords([
+  { object: obj, type: 'reconfigured', name: 'a' },
+  { object: obj, type: 'reconfigured', name: 'b' },
+  { object: obj, type: 'reconfigured', name: 'c' },
+  { object: obj, type: 'preventExtensions' },
+]);
+
+// Object.seal
+reset();
+var obj = { a: 'a' };
+Object.defineProperty(obj, 'b', {
+  writable: false,
+  configurable: true,
+  value: 'b'
+});
+Object.defineProperty(obj, 'c', {
+  writable: true,
+  configurable: false,
+  value: 'c'
+});
+Object.defineProperty(obj, 'd', {
+  writable: false,
+  configurable: false,
+  value: 'd'
+});
+Object.observe(obj, observer.callback);
+Object.seal(obj);
+
+Object.deliverChangeRecords(observer.callback);
+observer.assertCallbackRecords([
+  { object: obj, type: 'reconfigured', name: 'a' },
+  { object: obj, type: 'reconfigured', name: 'b' },
+  { object: obj, type: 'preventExtensions' },
+]);
+
 // Observing a continuous stream of changes, while itermittantly unobserving.
 reset();
+var obj = {};
 Object.observe(obj, observer.callback);
 Object.getNotifier(obj).notify({
   type: 'updated',
   val: 1
 });
 
 Object.unobserve(obj, observer.callback);
 Object.getNotifier(obj).notify({
   type: 'updated',
   val: 2
@@ skipping 1314 matching lines @@
     for (var n1 = 0; n1 < 3; ++n1)
       for (var n2 = 0; n2 < 3; ++n2)
         for (var i in mutation)
           TestFastElementsLength(mutation[i], b1 != 0, b2 != 0, 20*n1, 20*n2);
 
 for (var b1 = 0; b1 < 2; ++b1)
   for (var b2 = 0; b2 < 2; ++b2)
     for (var n = 0; n < 3; ++n)
       for (var i in mutationByIncr)
         TestFastElementsLength(mutationByIncr[i], b1 != 0, b2 != 0, 7*n, 7*n+1);