repl: Enable tab completion for global properties.

When `useGlobal` is false, tab completion in the repl does not enumerate global properties. Instead of just setting these properties blindly on the global context, e.g. context[prop] = global[prop] Use `Object.defineProperty` and the property descriptor found on `global` for the new property in `context`. Also addresses a previously unnoticed issue where `console` is writable when `useGlobal` is false. Ref: #7353
nodejs · lance · Jun 22, 2016 · Jun 23, 2016 · Jun 23, 2016 · Jun 24, 2016
commit dcaf20b30459f355cf885b3189f07f0b2eaff253
diff --git a/lib/repl.js b/lib/repl.js
@@ -582,10 +582,20 @@ REPLServer.prototype.createContext = function() {
     context = global;
   } else {
     context = vm.createContext();
-    for (var i in global) context[i] = global[i];
-    context.console = new Console(this.outputStream);
-    context.global = context;
-    context.global.global = context;
+    const _console = new Console(this.outputStream);
+    Object.getOwnPropertyNames(global).forEach((name) => {
+      if (name === 'console') {
+        Object.defineProperty(context, name, {
+          configurable: true,
+          enumerable: true,
+          value: _console
+        });
+      }
+      else {
+        Object.defineProperty(context, name,
+          Object.getOwnPropertyDescriptor(global, name));
+      }
+    });
   }
 
   const module = new Module('<repl>');

diff --git a/test/parallel/test-repl-console.js b/test/parallel/test-repl-console.js
@@ -18,3 +18,6 @@ assert(r.context.console);
 
 // ensure that the repl console instance is not the global one
 assert.notStrictEqual(r.context.console, console);
+
+// ensure that the repl console instance does not have a setter
+assert.throws(() => r.context.console = 'foo', TypeError);
diff --git a/test/parallel/test-repl-tab-complete.js b/test/parallel/test-repl-tab-complete.js
@@ -267,3 +267,14 @@ putIn.run(['.clear']);
 testMe.complete('.b', common.mustCall((error, data) => {
   assert.deepStrictEqual(data, [['break'], 'b']);
 }));
+
+var testNonGlobal = repl.start({
+  input: putIn,
+  output: putIn,
+  useGlobal: false
+});
+
+testNonGlobal.complete('I', common.mustCall((error, data) => {
+  assert.deepStrictEqual(data, [['Infinity', '', 'Int16Array', 'Int32Array',
+                                 'Int8Array', 'Intl'], 'I']);
+}));