Deprecate import Ember from 'ember'

RFC: emberjs/rfcs#1003
Guide: ember-learn/deprecation-app#1381
Advancement: emberjs/rfcs#1015

Author: NullVoxPopuli

packages/@ember/-internals/deprecations/index.ts

@@ -2,6 +2,7 @@ import type { DeprecationOptions } from '@ember/debug/lib/deprecate';
 import { ENV } from '@ember/-internals/environment';
 import { VERSION } from '@ember/version';
 import { deprecate, assert } from '@ember/debug';
+import { dasherize } from '../string/index';
 
 function isEnabled(options: DeprecationOptions) {
   return Object.hasOwnProperty.call(options.since, 'enabled') || ENV._ALL_DEPRECATIONS_ENABLED;
@@ -90,6 +91,17 @@ function deprecation(options: DeprecationOptions) {
   test the behavior without encountering the deprecated feature, just as users would.
  */
 export const DEPRECATIONS = {
+  DEPRECATE_IMPORT_EMBER(importName: string) {
+    return deprecation({
+      id: `deprecate-import-${dasherize(importName).toLowerCase()}-from-ember`,
+      for: 'ember-source',
+      since: { available: '5.9.0' },
+      until: '6.0.0',
+      url: `https://deprecations.emberjs.com/id/import-${dasherize(
+        importName
+      ).toLowerCase()}-from-ember`,
+    });
+  },
   DEPRECATE_IMPLICIT_ROUTE_MODEL: deprecation({
     id: 'deprecate-implicit-route-model',
     for: 'ember-source',

packages/ember-testing/tests/reexports_test.js

@@ -1,7 +1,8 @@
 import Ember from 'ember';
-import { confirmExport } from 'internal-test-helpers';
+import { confirmExport, testUnless } from 'internal-test-helpers';
 import { moduleFor, AbstractTestCase } from 'internal-test-helpers';
 import * as emberTesting from 'ember-testing';
+import { DEPRECATIONS } from '@ember/-internals/deprecations';
 
 class ReexportsTestCase extends AbstractTestCase {}
 
@@ -19,7 +20,15 @@ class ReexportsTestCase extends AbstractTestCase {}
     exportName = path;
   }
 
-  ReexportsTestCase.prototype[`@test Ember.${path} exports correctly`] = function (assert) {
+  ReexportsTestCase.prototype[
+    `${testUnless(
+      DEPRECATIONS.DEPRECATE_IMPORT_EMBER(path).isRemoved
+    )} Ember.${path} exports correctly`
+  ] = function (assert) {
+    expectDeprecation(
+      /'ember' barrel file is deprecated/,
+      DEPRECATIONS.DEPRECATE_IMPORT_EMBER(path || exportName).isEnabled
+    );
     confirmExport(Ember, assert, path, moduleId, exportName, emberTesting);
   };
 });