[BUGFIX beta] Fixes #14298 rendering aliased paths

When dirtying an object, other objects with aliases
that path through this object should dirty as well.

(cherry picked from commit 1cb8975)

packages/ember-glimmer/tests/integration/content-test.js

@@ -403,6 +403,45 @@ class DynamicContentTest extends RenderingTest {
     this.assertContent('hello');
     this.assertInvariants();
   }
+
+  ['@test it can render a readOnly property of a path']() {
+    let Messenger = EmberObject.extend({
+      message: computed.readOnly('a.b.c')
+    });
+
+    let messenger = Messenger.create({
+      a: {
+        b: {
+          c: 'hello'
+        }
+      }
+    });
+
+    this.renderPath('messenger.message', { messenger });
+
+    this.assertContent('hello');
+
+    this.assertStableRerender();
+
+    this.runTask(() => set(messenger, 'a.b.c', 'hi'));
+
+    this.assertContent('hi');
+    this.assertInvariants();
+
+    this.runTask(() => set(this.context, 'messenger.a.b', {
+      c: 'goodbye'
+    }));
+
+    this.assertContent('goodbye');
+    this.assertInvariants();
+
+    this.runTask(() => set(this.context, 'messenger', {
+      message: 'hello'
+    }));
+
+    this.assertContent('hello');
+    this.assertInvariants();
+  }
 }
 
 const EMPTY = {};

packages/ember-metal/lib/alias.js

@@ -34,27 +34,15 @@ AliasedProperty.prototype.set = function AliasedProperty_set(obj, keyName, value
   return set(obj, this.altKey, value);
 };
 
-AliasedProperty.prototype.willWatch = function(obj, keyName) {
-  addDependentKeys(this, obj, keyName, meta(obj));
-};
-
-AliasedProperty.prototype.didUnwatch = function(obj, keyName) {
-  removeDependentKeys(this, obj, keyName, meta(obj));
-};
-
 AliasedProperty.prototype.setup = function(obj, keyName) {
   assert(`Setting alias '${keyName}' on self`, this.altKey !== keyName);
   let m = meta(obj);
-  if (m.peekWatching(keyName)) {
-    addDependentKeys(this, obj, keyName, m);
-  }
+  addDependentKeys(this, obj, keyName, m);
 };
 
 AliasedProperty.prototype.teardown = function(obj, keyName) {
   let m = meta(obj);
-  if (m.peekWatching(keyName)) {
-    removeDependentKeys(this, obj, keyName, m);
-  }
+  removeDependentKeys(this, obj, keyName, m);
 };
 
 AliasedProperty.prototype.readOnly = function() {

packages/ember-metal/tests/alias_test.js

@@ -5,6 +5,7 @@ import { set } from '../property_set';
 import { meta } from '../meta';
 import { isWatching } from '../watching';
 import { addObserver, removeObserver } from '../observer';
+import { tagFor } from '../tags';
 
 let obj, count;
 
@@ -33,15 +34,6 @@ QUnit.test('should proxy set to alt key', function() {
   equal(get(obj, 'foo.faz'), 'BAR');
 });
 
-QUnit.test('basic lifecycle', function() {
-  defineProperty(obj, 'bar', alias('foo.faz'));
-  let m = meta(obj);
-  addObserver(obj, 'bar', incrementCount);
-  equal(m.peekDeps('foo.faz', 'bar'), 1);
-  removeObserver(obj, 'bar', incrementCount);
-  equal(m.peekDeps('foo.faz', 'bar'), 0);
-});
-
 QUnit.test('old dependent keys should not trigger property changes', function() {
   let obj1 = Object.create(null);
   defineProperty(obj1, 'foo', null, null);
@@ -59,8 +51,13 @@ QUnit.test('old dependent keys should not trigger property changes', function()
   equal(count, 1);
 });
 
-QUnit.test('overridden dependent keys should not trigger property changes', function() {
+QUnit.test(`inheriting an observer of the alias from the prototype then
+            redefining the alias on the instance to another property dependent on same key
+            does not call the observer twice`, function() {
   let obj1 = Object.create(null);
+
+  meta(obj1).proto = obj1;
+
   defineProperty(obj1, 'foo', null, null);
   defineProperty(obj1, 'bar', alias('foo'));
   defineProperty(obj1, 'baz', alias('foo'));
@@ -78,22 +75,34 @@ QUnit.test('overridden dependent keys should not trigger property changes', func
   equal(count, 1);
 });
 
-QUnit.test('begins watching alt key as soon as alias is watched', function() {
+QUnit.test('an observer of the alias works if added after defining the alias', function() {
   defineProperty(obj, 'bar', alias('foo.faz'));
   addObserver(obj, 'bar', incrementCount);
   ok(isWatching(obj, 'foo.faz'));
   set(obj, 'foo.faz', 'BAR');
   equal(count, 1);
 });
 
-QUnit.test('immediately sets up dependencies if already being watched', function() {
+QUnit.test('an observer of the alias works if added before defining the alias', function() {
   addObserver(obj, 'bar', incrementCount);
   defineProperty(obj, 'bar', alias('foo.faz'));
   ok(isWatching(obj, 'foo.faz'));
   set(obj, 'foo.faz', 'BAR');
   equal(count, 1);
 });
 
+QUnit.test('object with alias is dirtied if interior object of alias is set', function () {
+  defineProperty(obj, 'bar', alias('foo.faz'));
+  assertDirty(obj, () => set(obj, 'foo.faz', 'BAR'), 'setting the aliased key should dirty the object');
+});
+
 QUnit.test('setting alias on self should fail assertion', function() {
   expectAssertion(() => defineProperty(obj, 'bar', alias('bar')), 'Setting alias \'bar\' on self');
 });
+
+function assertDirty(obj, callback, label) {
+  let tag = tagFor(obj);
+  let tagValue = tag.value();
+  callback();
+  ok(!tag.validate(tagValue), label);
+}