Bug 893858 - More testing for CPOWs and fix some small bugs. r=dvander

content/base/test/chrome/cpows_child.js

@@ -27,8 +27,15 @@ function make_object()
   o.b = true;
   o.s = "hello";
   o.x = { i: 10 };
-  o.f = function () { return 99; }
+  o.f = function () { return 99; };
+
+  // Doing anything with this Proxy will throw.
+  var throwing = new Proxy({}, new Proxy({}, {
+      get: function (trap) { throw trap; }
+    }));
+
   return { "data": o,
+           "throwing": throwing,
            "document": content.document
          };
 }

content/base/test/chrome/cpows_parent.xul

@@ -37,6 +37,39 @@
       ok(data.b === false, "boolean property");
       ok(data.s === "bye", "string property");
       ok(data.x === null, "nested property");
+
+      let throwing = message.objects.throwing;
+      // Based on the table on:
+      // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy
+      let tests = [
+        () => Object.getOwnPropertyDescriptor(throwing, 'test'),
+        () => Object.getOwnPropertyNames(throwing),
+        () => Object.defineProperty(throwing, 'test', {value: 1}),
+        () => delete throwing.test,
+        () => "test" in throwing,
+        () => Object.prototype.hasOwnProperty.call(throwing, 'test'),
+        () => throwing.test,
+        () => { throwing.test = 1 },
+        // () => { for (let prop in throwing) {} }, Bug 783829
+        () => { for (let prop of throwing) {} },
+        () => Object.keys(throwing),
+        () => Function.prototype.call.call(throwing),
+        () => new throwing,
+        () => Object.preventExtensions(throwing),
+        () => Object.freeze(throwing),
+        () => Object.seal(throwing),
+      ]
+
+      for (let test of tests) {
+        let threw = false;
+        try {
+          test()
+        } catch (e) {
+          threw = true;
+        }
+        ok(threw, "proxy operation threw exception");
+      }
+
     }
 
     function recvAsyncMessage(message) {

js/ipc/JavaScriptChild.cpp

@@ -271,6 +271,8 @@ JavaScriptChild::AnswerDelete(const ObjectId &objId, const nsString &id, ReturnS
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
+    *success = false;
+
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;
@@ -299,6 +301,8 @@ JavaScriptChild::AnswerHas(const ObjectId &objId, const nsString &id, ReturnStat
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
+    *bp = false;
+
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;
@@ -323,6 +327,8 @@ JavaScriptChild::AnswerHasOwn(const ObjectId &objId, const nsString &id, ReturnS
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
+    *bp = false;
+
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;
@@ -434,7 +440,7 @@ JavaScriptChild::AnswerIsExtensible(const ObjectId &objId, ReturnStatus *rs, boo
         return fail(cx, rs);
 
     *result = !!extensible;
-    return true;
+    return ok(rs);
 }
 
 bool
@@ -548,7 +554,6 @@ JavaScriptChild::AnswerObjectClassIs(const ObjectId &objId, const uint32_t &clas
     JSAutoCompartment comp(cx, obj);
 
     *result = js_ObjectClassIs(cx, obj, (js::ESClassValue)classValue);
-
     return true;
 }
 
@@ -588,7 +593,7 @@ JavaScriptChild::AnswerGetPropertyNames(const ObjectId &objId, const uint32_t &f
     for (size_t i = 0; i < props.length(); i++) {
         nsString name;
         if (!convertIdToGeckoString(cx, props.handleAt(i), &name))
-            return false;
+            return fail(cx, rs);
 
         names->AppendElement(name);
     }
@@ -603,6 +608,8 @@ JavaScriptChild::AnswerInstanceOf(const ObjectId &objId, const JSIID &iid, Retur
     AutoSafeJSContext cx;
     JSAutoRequest request(cx);
 
+    *instanceof = false;
+
     RootedObject obj(cx, findObject(objId));
     if (!obj)
         return false;

js/src/jsapi.cpp

@@ -7212,12 +7212,11 @@ JS_GetScriptedGlobal(JSContext *cx)
 JS_PUBLIC_API(JSBool)
 JS_PreventExtensions(JSContext *cx, JS::HandleObject obj)
 {
-    JSBool extensible;
-    if (!JS_IsExtensible(cx, obj, &extensible))
-        return JS_TRUE;
-    if (extensible)
-        return JS_TRUE;
-
+    bool extensible;
+    if (!JSObject::isExtensible(cx, obj, &extensible))
+        return false;
+    if (!extensible)
+        return true;
     return JSObject::preventExtensions(cx, obj);
 }