[BUGFIX beta] Avoid extra work for Ember.Component#layout.

---

Prior to this change, `layout` was a CP that did a few things:

* `get(this, 'layoutName')` (and if set `this.container.lookup`)
* `get(this, 'defaultLayout')`

After this change, `layout` is a simple property that avoids that extra
work.

---

Prior to this change, `defaultLayout` would actually override a layout
that came from the container, this was incorrect (literally the opposite
of what we wanted).

This corrects that logic, and ensures that we only attempt to use the
`layout` property if the layout was not found during the container
lookup (which properly mimics the behavior in 1.0 - 1.12 where `layout`
was injected into the component if a layout was found in the container).

packages/ember-htmlbars/lib/node-managers/component-node-manager.js

@@ -73,7 +73,9 @@ ComponentNodeManager.create = function ComponentNodeManager_create(renderNode, e
   // If the component specifies its layout via the `layout` property
   // instead of using the template looked up in the container, get it
   // now that we have the component instance.
-  layout = get(component, 'layout') || layout;
+  if (!layout) {
+    layout = get(component, 'layout');
+  }
 
   runInDebug(() => {
     if (isAngleBracket) {

packages/ember-routing-views/lib/components/link-to.js

@@ -344,7 +344,7 @@ linkToTemplate.meta.revision = 'Ember@VERSION_STRING_PLACEHOLDER';
   @private
 **/
 let LinkComponent = EmberComponent.extend({
-  defaultLayout: linkToTemplate,
+  layout: linkToTemplate,
 
   tagName: 'a',
 

packages/ember-views/lib/components/component.js

@@ -1,5 +1,5 @@
 import Ember from 'ember-metal/core';
-import { assert } from 'ember-metal/debug';
+import { assert, deprecate } from 'ember-metal/debug';
 
 import TargetActionSupport from 'ember-runtime/mixins/target_action_support';
 import View from 'ember-views/views/view';
@@ -132,12 +132,33 @@ var Component = View.extend(TargetActionSupport, {
   }),
 
   init() {
-    this._super.apply(this, arguments);
+    this._super(...arguments);
     set(this, 'controller', this);
     set(this, 'context', this);
+
+    if (!this.layout && this.layoutName && this.container) {
+      let layoutName = get(this, 'layoutName');
+
+      this.layout = this.templateForName(layoutName);
+    }
+
+    // If a `defaultLayout` was specified move it to the `layout` prop.
+    // `layout` is no longer a CP, so this just ensures that the `defaultLayout`
+    // logic is supported with a deprecation
+    if (this.defaultLayout && !this.layout) {
+      deprecate(
+        `Specifying \`defaultLayout\` to ${this} is deprecated. Please use \`layout\` instead.`,
+        false,
+        { id: 'ember-views.component.defaultLayout', until: '3.0.0' }
+      );
+
+      this.layout = this.defaultLayout;
+    }
   },
 
   template: null,
+  layoutName: null,
+  layout: null,
 
   /**
     If the component is currently inserted into the DOM of a parent view, this

packages/ember-views/tests/views/component_test.js

@@ -62,6 +62,14 @@ QUnit.test('Specifying both templateName and layoutName to a component is NOT de
   equal(get(component, 'layoutName'), 'hum-drum');
 });
 
+QUnit.test('Specifying a defaultLayout to a component is deprecated', function() {
+  expectDeprecation(function() {
+    Component.extend({
+      defaultLayout: 'hum-drum'
+    }).create();
+  }, /Specifying `defaultLayout` to .+ is deprecated\./);
+});
+
 QUnit.test('Specifying a templateName on a component with a layoutName specified in a superclass is NOT deprecated', function() {
   expectNoDeprecation();
   var Parent = Component.extend({

packages/ember/tests/component_registration_test.js

@@ -134,7 +134,7 @@ QUnit.test('Component-like invocations are treated as bound paths if neither tem
   equal(Ember.$('#wrapper').text(), 'machty hello  world', 'The component is composed correctly');
 });
 
-QUnit.test('Assigning templateName to a component should setup the template as a layout', function() {
+QUnit.test('Assigning layoutName to a component should setup the template as a layout', function() {
   expect(1);
 
   Ember.TEMPLATES.application = compile('<div id=\'wrapper\'>{{#my-component}}{{text}}{{/my-component}}</div>');
@@ -154,6 +154,70 @@ QUnit.test('Assigning templateName to a component should setup the template as a
   equal(Ember.$('#wrapper').text(), 'inner-outer', 'The component is composed correctly');
 });
 
+QUnit.test('Assigning layoutName and layout to a component should use the `layout` value', function() {
+  expect(1);
+
+  Ember.TEMPLATES.application = compile('<div id=\'wrapper\'>{{#my-component}}{{text}}{{/my-component}}</div>');
+  Ember.TEMPLATES['foo-bar-baz'] = compile('No way!');
+
+  boot(function() {
+    registry.register('controller:application', Ember.Controller.extend({
+      'text': 'outer'
+    }));
+
+    registry.register('component:my-component', Ember.Component.extend({
+      text: 'inner',
+      layoutName: 'foo-bar-baz',
+      layout: compile('{{text}}-{{yield}}')
+    }));
+  });
+
+  equal(Ember.$('#wrapper').text(), 'inner-outer', 'The component is composed correctly');
+});
+
+QUnit.test('Assigning defaultLayout to a component should set it up as a layout if no layout was found [DEPRECATED]', function() {
+  expect(2);
+
+  Ember.TEMPLATES.application = compile('<div id=\'wrapper\'>{{#my-component}}{{text}}{{/my-component}}</div>');
+
+  expectDeprecation(function() {
+    boot(function() {
+      registry.register('controller:application', Ember.Controller.extend({
+        'text': 'outer'
+      }));
+
+      registry.register('component:my-component', Ember.Component.extend({
+        text: 'inner',
+        defaultLayout: compile('{{text}}-{{yield}}')
+      }));
+    });
+  }, /Specifying `defaultLayout` to .+ is deprecated\./);
+
+  equal(Ember.$('#wrapper').text(), 'inner-outer', 'The component is composed correctly');
+});
+
+QUnit.test('Assigning defaultLayout to a component should set it up as a layout if layout was found [DEPRECATED]', function() {
+  expect(2);
+
+  Ember.TEMPLATES.application = compile('<div id=\'wrapper\'>{{#my-component}}{{text}}{{/my-component}}</div>');
+  Ember.TEMPLATES['components/my-component'] = compile('{{text}}-{{yield}}');
+
+  expectDeprecation(function() {
+    boot(function() {
+      registry.register('controller:application', Ember.Controller.extend({
+        'text': 'outer'
+      }));
+
+      registry.register('component:my-component', Ember.Component.extend({
+        text: 'inner',
+        defaultLayout: compile('should not see this!')
+      }));
+    });
+  }, /Specifying `defaultLayout` to .+ is deprecated\./);
+
+  equal(Ember.$('#wrapper').text(), 'inner-outer', 'The component is composed correctly');
+});
+
 QUnit.test('Using name of component that does not exist', function () {
   Ember.TEMPLATES.application = compile('<div id=\'wrapper\'>{{#no-good}} {{/no-good}}</div>');