Bug 1341256 - Fix module namespace object get handler r=anba

js/src/builtin/ModuleObject.cpp

@@ -464,8 +464,10 @@ ModuleNamespaceObject::ProxyHandler::get(JSContext* cx, HandleObject proxy, Hand
 
     ModuleEnvironmentObject* env;
     Shape* shape;
-    if (!ns->bindings().lookup(id, &env, &shape))
+    if (!ns->bindings().lookup(id, &env, &shape)) {
-        return false;
+        vp.setUndefined();
+        return true;
+    }
 
     RootedValue value(cx, env->getSlot(shape->slot()));
     if (value.isMagic(JS_UNINITIALIZED_LEXICAL)) {

js/src/jit-test/tests/modules/import-namespace.js

@@ -45,6 +45,9 @@ b.evaluation();
 testHasNames(getModuleEnvironmentNames(b), ["ns", "x"]);
 let ns = getModuleEnvironmentValue(b, "ns");
 testHasNames(Object.keys(ns), ["a", "b"]);
+assertEq(ns.a, 1);
+assertEq(ns.b, 2);
+assertEq(ns.c, undefined);
 assertEq(getModuleEnvironmentValue(b, "x"), 3);
 
 // Test module namespace internal methods as defined in 9.4.6