[strong] Add tests for loading from proxy, super, with access checks

test/mjsunit/strong/load-proxy.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-proxies --strong-mode
+
+// Forwarding proxies adapted from proposal definition
+function handlerMaker1(obj) {
+  return {
+    getPropertyDescriptor: function(name) {
+      var desc;
+      var searchObj = obj;
+      while (desc === undefined && searchObj != null) {
+        desc = Object.getOwnPropertyDescriptor(searchObj, name);
+        searchObj = searchObj.__proto__;
+      }
+      // a trapping proxy's properties must always be configurable
+      if (desc !== undefined) { desc.configurable = true; }
+      return desc;
+    },
+    fix: function() {
+      if (Object.isFrozen(obj)) {
+        var result = {};
+        Object.getOwnPropertyNames(obj).forEach(function(name) {
+          result[name] = Object.getOwnPropertyDescriptor(obj, name);
+        });
+        return result;
+      }
+      // As long as obj is not frozen, the proxy won't allow itself to be fixed
+      return undefined; // will cause a TypeError to be thrown
+    }
+  };
+}
+function handlerMaker2(obj) {
+  return {
+    get: function(receiver, name) {
+      return obj[name];
+    },
+    fix: function() {
+      if (Object.isFrozen(obj)) {
+        var result = {};
+        Object.getOwnPropertyNames(obj).forEach(function(name) {
+          result[name] = Object.getOwnPropertyDescriptor(obj, name);
+        });
+        return result;
+      }
+      // As long as obj is not frozen, the proxy won't allow itself to be fixed
+      return undefined; // will cause a TypeError to be thrown
+    }
+  };
+}
+var baseObj = {};
+var proxy1 = Proxy.create(handlerMaker1(baseObj));
+var proxy2 = Proxy.create(handlerMaker2(baseObj));
+var childObj1 = { __proto__: proxy1 };
+var childObj2 = { __proto__: proxy2 };
+var childObjAccessor1 = { set foo(_){}, set "1"(_){}, __proto__: proxy1 };
+var childObjAccessor2 = { set foo(_){}, set "1"(_){}, __proto__: proxy2 };
+
+(function() {
+  "use strong";
+  assertDoesNotThrow(function(){proxy1.foo});

[rossberg, 2015/06/30 12:38:03]

Maybe add an explanatory TODO here that says that this is merely a sanity test,
and probably not the semantics we ultimately want for proxies.

[conradw, 2015/06/30 15:12:56]

Done.

+  assertDoesNotThrow(function(){proxy1[1]});
+  assertDoesNotThrow(function(){proxy2.foo});
+  assertDoesNotThrow(function(){proxy2[1]});
+  assertDoesNotThrow(function(){childObj1.foo});
+  assertDoesNotThrow(function(){childObj1[1]});
+  assertDoesNotThrow(function(){childObj2.foo});
+  assertDoesNotThrow(function(){childObj2[1]});
+  assertThrows(function(){baseObj.foo}, TypeError);
+  assertThrows(function(){baseObj[1]}, TypeError);
+  assertThrows(function(){childObjAccessor1.foo}, TypeError);
+  assertThrows(function(){childObjAccessor1[1]}, TypeError);
+  assertThrows(function(){childObjAccessor2.foo}, TypeError);
+  assertThrows(function(){childObjAccessor2[1]}, TypeError);
+
+  // Once the proxy is no longer trapping, property access should have strong
+  // semantics.
+  Object.freeze(baseObj);
+  Object.freeze(proxy1);
+  Object.freeze(proxy2);
+  assertThrows(function(){proxy1.foo}, TypeError);
+  assertThrows(function(){proxy1[1]}, TypeError);
+  assertThrows(function(){proxy2.foo}, TypeError);
+  assertThrows(function(){proxy2[1]}, TypeError);
+  assertThrows(function(){childObj1.foo}, TypeError);
+  assertThrows(function(){childObj1[1]}, TypeError);
+  assertThrows(function(){childObj2.foo}, TypeError);
+  assertThrows(function(){childObj2[1]}, TypeError);
+  assertThrows(function(){childObjAccessor1.foo}, TypeError);
+  assertThrows(function(){childObjAccessor1[1]}, TypeError);
+  assertThrows(function(){childObjAccessor2.foo}, TypeError);
+  assertThrows(function(){childObjAccessor2[1]}, TypeError);
+})();