[DONT BACKPORT][BUGFIX lts] Make {{hash}} object properties settable

package.json

@@ -51,7 +51,7 @@
     "@babel/plugin-transform-block-scoping": "^7.8.3",
     "@babel/plugin-transform-object-assign": "^7.8.3",
     "@ember/edition-utils": "^1.2.0",
-    "@glimmer/vm-babel-plugins": "0.79.1",
+    "@glimmer/vm-babel-plugins": "0.79.2",
     "babel-plugin-debug-macros": "^0.3.3",
     "babel-plugin-filter-imports": "^4.0.0",
     "broccoli-concat": "^4.2.4",
@@ -75,19 +75,19 @@
   },
   "devDependencies": {
     "@babel/preset-env": "^7.9.5",
-    "@glimmer/compiler": "0.79.1",
-    "@glimmer/destroyable": "0.79.1",
+    "@glimmer/compiler": "0.79.2",
+    "@glimmer/destroyable": "0.79.2",
     "@glimmer/env": "^0.1.7",
-    "@glimmer/global-context": "0.79.1",
-    "@glimmer/interfaces": "0.79.1",
-    "@glimmer/manager": "0.79.1",
-    "@glimmer/node": "0.79.1",
-    "@glimmer/opcode-compiler": "0.79.1",
-    "@glimmer/owner": "0.79.1",
-    "@glimmer/program": "0.79.1",
-    "@glimmer/reference": "0.79.1",
-    "@glimmer/runtime": "0.79.1",
-    "@glimmer/validator": "0.79.1",
+    "@glimmer/global-context": "0.79.2",
+    "@glimmer/interfaces": "0.79.2",
+    "@glimmer/manager": "0.79.2",
+    "@glimmer/node": "0.79.2",
+    "@glimmer/opcode-compiler": "0.79.2",
+    "@glimmer/owner": "0.79.2",
+    "@glimmer/program": "0.79.2",
+    "@glimmer/reference": "0.79.2",
+    "@glimmer/runtime": "0.79.2",
+    "@glimmer/validator": "0.79.2",
     "@simple-dom/document": "^1.4.0",
     "@types/qunit": "^2.11.1",
     "@types/rsvp": "^4.0.3",

packages/@ember/-internals/glimmer/lib/environment.ts

@@ -125,6 +125,14 @@ const VM_DEPRECATION_OVERRIDES: (DeprecationOptions & {
       enabled: '3.27.0',
     },
   },
+  {
+    id: 'setting-on-hash',
+    until: '4.4.0',
+    for: 'ember-source',
+    since: {
+      enabled: '3.28.0',
+    },
+  },
 ];
 
 const VM_ASSERTION_OVERRIDES: { id: string; message: string }[] = [];

packages/@ember/-internals/glimmer/tests/integration/helpers/hash-test.js

@@ -2,7 +2,8 @@ import { RenderingTestCase, moduleFor, runTask } from 'internal-test-helpers';
 
 import { Component } from '../../utils/helpers';
 
-import { set } from '@ember/-internals/metal';
+import { set, computed } from '@ember/-internals/metal';
+import { HAS_NATIVE_PROXY } from '@ember/-internals/utils';
 
 moduleFor(
   'Helpers test: {{hash}}',
@@ -186,5 +187,78 @@ moduleFor(
 
       this.assertText('Chad Hietala');
     }
+
+    ['@test works with computeds']() {
+      let FooBarComponent = Component.extend({
+        fullName: computed('hash.firstName', 'hash.lastName', function () {
+          return `${this.hash.firstName} ${this.hash.lastName}`;
+        }),
+      });
+
+      this.registerComponent('foo-bar', {
+        ComponentClass: FooBarComponent,
+        template: `{{this.fullName}}`,
+      });
+
+      this.render(`{{foo-bar hash=(hash firstName=this.firstName lastName=this.lastName)}}`, {
+        firstName: 'Chad',
+        lastName: 'Hietala',
+      });
+
+      this.assertText('Chad Hietala');
+
+      runTask(() => this.rerender());
+
+      this.assertText('Chad Hietala');
+
+      runTask(() => {
+        set(this.context, 'firstName', 'Godfrey');
+        set(this.context, 'lastName', 'Chan');
+      });
+
+      this.assertText('Godfrey Chan');
+    }
+
+    ['@test works when properties are set dynamically']() {
+      let fooBarInstance;
+      let FooBarComponent = Component.extend({
+        init() {
+          this._super();
+          fooBarInstance = this;
+        },
+      });
+
+      this.registerComponent('foo-bar', {
+        ComponentClass: FooBarComponent,
+        template: `{{this.hash.firstName}} {{this.hash.lastName}}`,
+      });
+
+      this.render(`{{foo-bar hash=(hash firstName=this.firstName)}}`, {
+        firstName: 'Chad',
+      });
+
+      this.assertText('Chad ');
+
+      runTask(() => {
+        if (HAS_NATIVE_PROXY) {
+          expectDeprecation(() => {
+            set(fooBarInstance.hash, 'lastName', 'Hietala');
+          }, /You set the '.*' property on a {{hash}} object/);
+        } else {
+          set(fooBarInstance.hash, 'lastName', 'Hietala');
+        }
+      });
+
+      this.assertText('Chad Hietala');
+
+      runTask(() => {
+        expectDeprecation(() => {
+          set(fooBarInstance.hash, 'firstName', 'Godfrey');
+          set(fooBarInstance.hash, 'lastName', 'Chan');
+        }, /You set the '.*' property on a {{hash}} object/);
+      });
+
+      this.assertText('Godfrey Chan');
+    }
   }
 );