Make Function.length and Function.name configurable properties.

test/mjsunit/harmony/object-observe.js

Index: test/mjsunit/harmony/object-observe.js
diff --git a/test/mjsunit/harmony/object-observe.js b/test/mjsunit/harmony/object-observe.js
index 72a9cadbf8ecb9df05a37593055e58e3c44f7efc..49822d251540e697f3a356b4417aad143465b6c0 100644
--- a/test/mjsunit/harmony/object-observe.js
+++ b/test/mjsunit/harmony/object-observe.js
@@ -975,16 +975,26 @@ observer.assertNotCalled();
 
 
 // Test all kinds of objects generically.
-function TestObserveConfigurable(obj, prop) {
+function TestObserveConfigurable(obj, prop, is_writable) {
   reset();
+  var valueWhenDeleted = is_writable ? 3 : obj[prop];
   Object.observe(obj, observer.callback);
   Object.unobserve(obj, observer.callback);
   obj[prop] = 1;
   Object.observe(obj, observer.callback);
   obj[prop] = 2;
-  obj[prop] = 3;
+  obj[prop] = valueWhenDeleted;
   delete obj[prop];
-  obj[prop] = 4;
+  // If the deleted obj[prop] exposed another 'prop' along
+  // the prototype chain, do not update it, but create an
+  // own property with the descriptor that [[Put]] mandates
+  // for a new property (ES-5.1, 8.12.5.6)
+  //
+  // (Q: do this unconditionally?)
+  if (Object.getPrototypeOf(obj) && (prop in Object.getPrototypeOf(obj)))

[rossberg, 2014/01/09 12:26:39]

Only do this fall-back when really necessary, i.e., if the inherited property is
read-only (or a JS accessor, but I don't think that comes up here).

Nit: redundant parens

[sof, 2014/01/09 14:04:51]

Done, I think (but it feels counterintuitive to "reuse" any property up the
prototype chain in this test.)

+    Object.defineProperty(obj, prop, {value: 4, writable: true, enumerable: true, configurable: true});

[rossberg, 2014/01/09 12:26:39]

Nit: line length

+  else
+    obj[prop] = 4;
   obj[prop] = 4;  // ignored
   obj[prop] = 5;
   Object.defineProperty(obj, prop, {value: 6});
@@ -1014,34 +1024,40 @@ function TestObserveConfigurable(obj, prop) {
   delete obj[prop];
   Object.defineProperty(obj, prop, {value: 11, configurable: true});
   Object.deliverChangeRecords(observer.callback);
-  observer.assertCallbackRecords([
-    { object: obj, name: prop, type: "update", oldValue: 1 },
-    { object: obj, name: prop, type: "update", oldValue: 2 },
-    { object: obj, name: prop, type: "delete", oldValue: 3 },
-    { object: obj, name: prop, type: "add" },
-    { object: obj, name: prop, type: "update", oldValue: 4 },
-    { object: obj, name: prop, type: "update", oldValue: 5 },
-    { object: obj, name: prop, type: "reconfigure" },
-    { object: obj, name: prop, type: "update", oldValue: 6 },
-    { object: obj, name: prop, type: "reconfigure", oldValue: 8 },
-    { object: obj, name: prop, type: "reconfigure", oldValue: 7 },
-    { object: obj, name: prop, type: "reconfigure" },
-    { object: obj, name: prop, type: "reconfigure" },
-    { object: obj, name: prop, type: "reconfigure" },
-    { object: obj, name: prop, type: "reconfigure" },
-    { object: obj, name: prop, type: "reconfigure" },
-    { object: obj, name: prop, type: "delete" },
-    { object: obj, name: prop, type: "add" },
-    { object: obj, name: prop, type: "delete" },
-    { object: obj, name: prop, type: "add" },
-    { object: obj, name: prop, type: "reconfigure" },
-    { object: obj, name: prop, type: "update", oldValue: 9 },
-    { object: obj, name: prop, type: "update", oldValue: 10 },
-    { object: obj, name: prop, type: "update", oldValue: 11 },
-    { object: obj, name: prop, type: "update", oldValue: 12 },
-    { object: obj, name: prop, type: "delete", oldValue: 36 },
-    { object: obj, name: prop, type: "add" },
-  ]);
+
+  var expected = [
+     { object: obj, name: prop, type: "delete", oldValue: valueWhenDeleted },
+     { object: obj, name: prop, type: "add" },
+     { object: obj, name: prop, type: "update", oldValue: 4 },
+     { object: obj, name: prop, type: "update", oldValue: 5 },
+     { object: obj, name: prop, type: "reconfigure" },
+     { object: obj, name: prop, type: "update", oldValue: 6 },
+     { object: obj, name: prop, type: "reconfigure", oldValue: 8 },
+     { object: obj, name: prop, type: "reconfigure", oldValue: 7 },
+     { object: obj, name: prop, type: "reconfigure" },
+     { object: obj, name: prop, type: "reconfigure" },
+     { object: obj, name: prop, type: "reconfigure" },
+     { object: obj, name: prop, type: "reconfigure" },
+     { object: obj, name: prop, type: "reconfigure" },
+     { object: obj, name: prop, type: "delete" },
+     { object: obj, name: prop, type: "add" },
+     { object: obj, name: prop, type: "delete" },
+     { object: obj, name: prop, type: "add" },
+     { object: obj, name: prop, type: "reconfigure" },
+     { object: obj, name: prop, type: "update", oldValue: 9 },
+     { object: obj, name: prop, type: "update", oldValue: 10 },
+     { object: obj, name: prop, type: "update", oldValue: 11 },
+     { object: obj, name: prop, type: "update", oldValue: 12 },
+     { object: obj, name: prop, type: "delete", oldValue: 36 },
+     { object: obj, name: prop, type: "add" },
+  ];
+
+  if (is_writable) {
+      expected.unshift({ object: obj, name: prop, type: "update", oldValue: 1 },
+                       { object: obj, name: prop, type: "update", oldValue: 2 });
+  }
+
+  observer.assertCallbackRecords(expected);
   Object.unobserve(obj, observer.callback);
   delete obj[prop];
 }
@@ -1143,7 +1159,7 @@ for (var i in objects) for (var j in properties) {
   var desc = Object.getOwnPropertyDescriptor(obj, prop);
   print("***", typeof obj, stringifyNoThrow(obj), prop);
   if (!desc || desc.configurable)
-    TestObserveConfigurable(obj, prop);
+    TestObserveConfigurable(obj, prop, !desc || desc.writable);
   else if (desc.writable)
     TestObserveNonConfigurable(obj, prop, desc);
 }