Fix Ember global deprecation

A minimal fix for #600. We should probably follow through with the
refactor suggested by @rwjblue in #600 but that can be done later.

This is probably not very embroider friendly, but neither is the
current code. It's probably easier to just rewrite the shims in
terms of ES modules and embroider macros, i.e. what was suggested
in #337.

assets/browser-fetch.js.t

@@ -1,7 +1,5 @@
 (function (originalGlobal) {
-  define('fetch', ['exports'], function(exports) {
-    'use strict';
-    var Promise = originalGlobal.Ember.RSVP.Promise;
+  <%= moduleHeader %>
     var supportProps = [
       'FormData',
       'FileReader',
@@ -49,8 +47,8 @@
       return result;
     }
 
-    if (originalGlobal.Ember.Test) {
-      originalGlobal.Ember.Test.registerWaiter(function() {
+    if (Ember.Test) {
+      Ember.Test.registerWaiter(function() {
         return pending === 0;
       });
 

index.js

@@ -27,6 +27,7 @@ const map = stew.map;
 const Rollup = require('broccoli-rollup');
 const BroccoliDebug = require('broccoli-debug');
 const calculateCacheKeyForTree = require('calculate-cache-key-for-tree');
+const VersionChecker = require('ember-cli-version-checker');
 
 const debug = BroccoliDebug.buildDebugCallback('ember-fetch');
 
@@ -73,6 +74,9 @@ module.exports = {
     let hasEmberFetch = !!this.project.findAddonByName('ember-fetch');
     let hasEmberCliFastboot = !!this.project.findAddonByName('ember-cli-fastboot');
 
+    let emberSource = new VersionChecker(this.project).for('ember-source');
+    let hasEmberSourceModules = emberSource.exists() && emberSource.gte('3.27.0');
+
     if(isApp && hasEmberCliFastboot && !hasEmberFetch) {
       throw new Error(`Ember fetch is not installed as top-level dependency of the application using fastboot. Add ember-fetch as dependecy in application's package.json.
       For details check here - https://github.com/ember-cli/ember-fetch#top-level-addon`);
@@ -88,6 +92,7 @@ module.exports = {
     app._fetchBuildConfig = Object.assign({
       preferNative: false,
       alwaysIncludePolyfill: false,
+      hasEmberSourceModules,
       browsers: this.project.targets && this.project.targets.browsers
     }, app.options['ember-fetch']);
 
@@ -216,8 +221,19 @@ module.exports = {
       sourceMapConfig: { enabled: false }
     }), 'after-concat');
 
+    const moduleHeader = options.hasEmberSourceModules ? `
+  define('fetch', ['exports', 'ember', 'rsvp'], function(exports, Ember__module, RSVP__module) {
+    'use strict';
+    var Ember = 'default' in Ember__module ? Ember__module['default'] : Ember__module;
+    var RSVP = 'default' in RSVP__module ? RSVP__module['default'] : RSVP__module;` : `
+  define('fetch', ['exports'], function(exports) {
+    'use strict';
+    var Ember = originalGlobal.Ember;
+    var RSVP = Ember.RSVP;`
+
     return debug(new Template(polyfillNode, TEMPLATE_PATH, function(content) {
       return {
+        moduleHeader,
         moduleBody: content
       };
     }), 'browser-fetch');

package.json

@@ -36,6 +36,7 @@
     "caniuse-api": "^3.0.0",
     "ember-cli-babel": "^7.23.1",
     "ember-cli-typescript": "^3.1.3",
+    "ember-cli-version-checker": "^5.1.2",
     "node-fetch": "^2.6.1",
     "whatwg-fetch": "^3.6.2"
   },