Remove ember-application-engines feature flag.

Flag has been enabled by default :)

features.json

@@ -3,7 +3,6 @@
     "features-stripped-test": null,
     "ember-routing-route-configured-query-params": null,
     "ember-libraries-isregistered": null,
-    "ember-application-engines": true,
     "ember-runtime-computed-uniq-by": true,
     "ember-improved-instrumentation": null,
     "ember-runtime-enumerable-includes": true,

packages/ember-application/lib/index.js

@@ -1,5 +1,4 @@
 import Ember from 'ember-metal/core'; // reexports
-import isEnabled from 'ember-metal/features';
 import { runLoadHooks } from 'ember-runtime/system/lazy_load';
 
 /**
@@ -17,17 +16,11 @@ import Engine from './system/engine';
 import EngineInstance from './system/engine-instance';
 
 Ember.Application = Application;
+Ember.ApplicationInstance = ApplicationInstance;
+Ember.Engine = Engine;
+Ember.EngineInstance = EngineInstance;
 Ember.DefaultResolver = Ember.Resolver = DefaultResolver;
 
-if (isEnabled('ember-application-engines')) {
-  Ember.Engine = Engine;
-
-  // Expose `EngineInstance` and `ApplicationInstance` for easy overriding.
-  // Reanalyze whether to continue exposing these after feature flag is removed.
-  Ember.EngineInstance = EngineInstance;
-  Ember.ApplicationInstance = ApplicationInstance;
-}
-
 // add domTemplates initializer (only does something if `ember-template-compiler`
 // is loaded already)
 import './initializers/dom-templates';

packages/ember-application/lib/system/engine-instance.js

@@ -14,7 +14,6 @@ import { assert } from 'ember-metal/debug';
 import run from 'ember-metal/run_loop';
 import RSVP from 'ember-runtime/ext/rsvp';
 import { guidFor } from 'ember-metal/utils';
-import isEnabled from 'ember-metal/features';
 
 /**
   The `EngineInstance` encapsulates all of the stateful aspects of a
@@ -25,7 +24,6 @@ import isEnabled from 'ember-metal/features';
   @extends Ember.Object
   @uses RegistryProxyMixin
   @uses ContainerProxyMixin
-  @category ember-application-engines
 */
 
 const EngineInstance = EmberObject.extend(RegistryProxy, ContainerProxy, {
@@ -101,9 +99,7 @@ const EngineInstance = EmberObject.extend(RegistryProxy, ContainerProxy, {
 
     assert('An engine instance\'s parent must be set via `setEngineParent(engine, parent)` prior to calling `engine.boot()`.', getEngineParent(this));
 
-    if (isEnabled('ember-application-engines')) {
-      this.cloneParentDependencies();
-    }
+    this.cloneParentDependencies();
 
     this.setupRegistry(options);
 
@@ -139,6 +135,66 @@ const EngineInstance = EmberObject.extend(RegistryProxy, ContainerProxy, {
   willDestroy() {
     this._super(...arguments);
     run(this.__container__, 'destroy');
+  },
+
+  /**
+    Build a new `Ember.EngineInstance` that's a child of this instance.
+
+    Engines must be registered by name with their parent engine
+    (or application).
+
+    @private
+    @method buildChildEngineInstance
+    @param name {String} the registered name of the engine.
+    @param options {Object} options provided to the engine instance.
+    @return {Ember.EngineInstance,Error}
+  */
+  buildChildEngineInstance(name, options = {}) {
+    let Engine = this.lookup(`engine:${name}`);
+
+    if (!Engine) {
+      throw new EmberError(`You attempted to mount the engine '${name}', but it is not registered with its parent.`);
+    }
+
+    let engineInstance = Engine.buildInstance(options);
+
+    setEngineParent(engineInstance, this);
+
+    return engineInstance;
+  },
+
+  /**
+    Clone dependencies shared between an engine instance and its parent.
+
+    @private
+    @method cloneParentDependencies
+  */
+  cloneParentDependencies() {
+    let parent = getEngineParent(this);
+
+    let registrations = [
+      'route:basic',
+      'event_dispatcher:main',
+      'service:-routing',
+      'service:-glimmer-environment'
+    ];
+
+    registrations.forEach(key => this.register(key, parent.resolveRegistration(key)));
+
+    let env = parent.lookup('-environment:main');
+    this.register('-environment:main', env, { instantiate: false });
+
+    let singletons = [
+      'router:main',
+      P`-bucket-cache:main`,
+      '-view-registry:main',
+      `renderer:-${env.isInteractive ? 'dom' : 'inert'}`
+    ];
+
+    singletons.forEach(key => this.register(key, parent.lookup(key), { instantiate: false }));
+
+    this.inject('view', '_environment', '-environment:main');
+    this.inject('route', '_environment', '-environment:main');
   }
 });
 
@@ -166,68 +222,4 @@ EngineInstance.reopenClass({
   }
 });
 
-if (isEnabled('ember-application-engines')) {
-  EngineInstance.reopen({
-    /**
-      Build a new `Ember.EngineInstance` that's a child of this instance.
-
-      Engines must be registered by name with their parent engine
-      (or application).
-
-      @private
-      @method buildChildEngineInstance
-      @param name {String} the registered name of the engine.
-      @param options {Object} options provided to the engine instance.
-      @return {Ember.EngineInstance,Error}
-    */
-    buildChildEngineInstance(name, options = {}) {
-      let Engine = this.lookup(`engine:${name}`);
-
-      if (!Engine) {
-        throw new EmberError(`You attempted to mount the engine '${name}', but it is not registered with its parent.`);
-      }
-
-      let engineInstance = Engine.buildInstance(options);
-
-      setEngineParent(engineInstance, this);
-
-      return engineInstance;
-    },
-
-    /**
-      Clone dependencies shared between an engine instance and its parent.
-
-      @private
-      @method cloneParentDependencies
-    */
-    cloneParentDependencies() {
-      let parent = getEngineParent(this);
-
-      let registrations = [
-        'route:basic',
-        'event_dispatcher:main',
-        'service:-routing',
-        'service:-glimmer-environment'
-      ];
-
-      registrations.forEach(key => this.register(key, parent.resolveRegistration(key)));
-
-      let env = parent.lookup('-environment:main');
-      this.register('-environment:main', env, { instantiate: false });
-
-      let singletons = [
-        'router:main',
-        P`-bucket-cache:main`,
-        '-view-registry:main',
-        `renderer:-${env.isInteractive ? 'dom' : 'inert'}`
-      ];
-
-      singletons.forEach(key => this.register(key, parent.lookup(key), { instantiate: false }));
-
-      this.inject('view', '_environment', '-environment:main');
-      this.inject('route', '_environment', '-environment:main');
-    }
-  });
-}
-
 export default EngineInstance;

packages/ember-application/lib/system/engine.js

@@ -47,7 +47,6 @@ function props(obj) {
   @namespace Ember
   @extends Ember.Namespace
   @uses RegistryProxy
-  @category ember-application-engines
   @public
 */
 const Engine = Namespace.extend(RegistryProxy, {

packages/ember-application/tests/system/application_instance_test.js

@@ -4,7 +4,6 @@ import ApplicationInstance from 'ember-application/system/application-instance';
 import run from 'ember-metal/run_loop';
 import jQuery from 'ember-views/system/jquery';
 import factory from 'container/tests/test-helpers/factory';
-import isEnabled from 'ember-metal/features';
 import { privatize as P } from 'container';
 import EmberObject from 'ember-runtime/system/object';
 
@@ -139,67 +138,65 @@ QUnit.test('unregistering a factory clears all cached instances of that factory'
   assert.notStrictEqual(postController1, postController2, 'lookup creates a brand new instance, because the previous one was reset');
 });
 
-if (isEnabled('ember-application-engines')) {
-  QUnit.test('can build and boot a registered engine', function(assert) {
-    assert.expect(10);
+QUnit.test('can build and boot a registered engine', function(assert) {
+  assert.expect(10);
 
-    let ChatEngine = Engine.extend();
-    let chatEngineInstance;
+  let ChatEngine = Engine.extend();
+  let chatEngineInstance;
 
-    application.register('engine:chat', ChatEngine);
+  application.register('engine:chat', ChatEngine);
 
-    run(() => {
-      appInstance = ApplicationInstance.create({ application });
-      appInstance.setupRegistry();
-      chatEngineInstance = appInstance.buildChildEngineInstance('chat');
-    });
+  run(() => {
+    appInstance = ApplicationInstance.create({ application });
+    appInstance.setupRegistry();
+    chatEngineInstance = appInstance.buildChildEngineInstance('chat');
+  });
 
-    return chatEngineInstance.boot()
-      .then(() => {
-        assert.ok(true, 'boot successful');
-
-        let registrations = [
-          'route:basic',
-          'event_dispatcher:main',
-          'service:-routing',
-          'service:-glimmer-environment'
-        ];
-
-        registrations.forEach(key => {
-          assert.strictEqual(
-            chatEngineInstance.resolveRegistration(key),
-            appInstance.resolveRegistration(key),
-            `Engine and parent app share registrations for '${key}'`);
-        });
-
-        let singletons = [
-          'router:main',
-          P`-bucket-cache:main`,
-          '-view-registry:main',
-          '-environment:main'
-        ];
-
-        let env = appInstance.lookup('-environment:main');
-        singletons.push(env.isInteractive ? 'renderer:-dom' : 'renderer:-inert');
-
-        singletons.forEach(key => {
-          assert.strictEqual(
-            chatEngineInstance.lookup(key),
-            appInstance.lookup(key),
-            `Engine and parent app share singleton '${key}'`);
-        });
+  return chatEngineInstance.boot()
+    .then(() => {
+      assert.ok(true, 'boot successful');
+
+      let registrations = [
+        'route:basic',
+        'event_dispatcher:main',
+        'service:-routing',
+        'service:-glimmer-environment'
+      ];
+
+      registrations.forEach(key => {
+        assert.strictEqual(
+          chatEngineInstance.resolveRegistration(key),
+          appInstance.resolveRegistration(key),
+          `Engine and parent app share registrations for '${key}'`);
       });
-  });
 
-  QUnit.test('can build a registry via Ember.ApplicationInstance.setupRegistry() -- simulates ember-test-helpers', function(assert) {
-    let namespace = EmberObject.create({
-      Resolver: { create: function() { } }
+      let singletons = [
+        'router:main',
+        P`-bucket-cache:main`,
+        '-view-registry:main',
+        '-environment:main'
+      ];
+
+      let env = appInstance.lookup('-environment:main');
+      singletons.push(env.isInteractive ? 'renderer:-dom' : 'renderer:-inert');
+
+      singletons.forEach(key => {
+        assert.strictEqual(
+          chatEngineInstance.lookup(key),
+          appInstance.lookup(key),
+          `Engine and parent app share singleton '${key}'`);
+      });
     });
+});
 
-    let registry = Application.buildRegistry(namespace);
+QUnit.test('can build a registry via Ember.ApplicationInstance.setupRegistry() -- simulates ember-test-helpers', function(assert) {
+  let namespace = EmberObject.create({
+    Resolver: { create: function() { } }
+  });
 
-    ApplicationInstance.setupRegistry(registry);
+  let registry = Application.buildRegistry(namespace);
 
-    assert.equal(registry.resolve('service:-document'), document);
-  });
-}
+  ApplicationInstance.setupRegistry(registry);
+
+  assert.equal(registry.resolve('service:-document'), document);
+});