[BUGFIX lts] Ensure transpiled builds work when babel helpers are not externalized

lib/index.js

@@ -7,6 +7,7 @@ const resolve = require('resolve');
 const concatBundle = require('./concat-bundle');
 const buildDebugMacroPlugin = require('./build-debug-macro-plugin');
 const buildStripClassCallcheckPlugin = require('./build-strip-class-callcheck-plugin');
+const injectBabelHelpers = require('./transforms/inject-babel-helpers');
 
 const isProduction = process.env.EMBER_ENV === 'production';
 
@@ -71,6 +72,10 @@ module.exports = {
     let appOptions = this.app && this.app.options;
     let babelOptions = (parentOptions || appOptions || {}).babel;
 
+    // We want to enable async/generator helpers if we are developing locally,
+    // but not for any other project.
+    let isEmberSource = this.project.name() === 'ember-source';
+
     let options = {
       'ember-cli-babel': {
         disableDebugTooling: true,
@@ -79,6 +84,7 @@ module.exports = {
       babel: Object.assign({}, babelOptions, {
         loose: true,
         plugins: [
+          injectBabelHelpers(isEmberSource),
           buildDebugMacroPlugin(!isProduction),
           [
             require.resolve('@babel/plugin-transform-block-scoping'),
@@ -157,6 +163,11 @@ module.exports = {
       files: ['jquery.js'],
     });
 
+    let templateCompiler = new Funnel(tree, {
+      destDir: 'ember',
+      include: ['ember-template-compiler.js', 'ember-template-compiler.map'],
+    });
+
     let ember;
     let targets = (this.project && this.project.targets && this.project.targets.browsers) || [];
 
@@ -174,6 +185,6 @@ module.exports = {
       });
     }
 
-    return new MergeTrees([ember, jquery]);
+    return new MergeTrees([ember, templateCompiler, jquery]);
   },
 };

lib/transforms/inject-babel-helpers.js

@@ -0,0 +1,31 @@
+'use strict';
+
+const { addNamed } = require('@babel/helper-module-imports');
+
+function injectBabelHelpers(isEmberSource = false) {
+  function injectBabelHelpersPlugin() {
+    return {
+      pre(file) {
+        file.set('helperGenerator', function(name) {
+          if (name === 'extends') {
+            return addNamed(file.path, 'assign', '@ember/polyfills');
+          } else if (isEmberSource && name === 'asyncToGenerator') {
+            // Returning a falsy value will cause the helper to be inlined,
+            // which is fine for local tests
+            return false;
+          }
+
+          return addNamed(file.path, name, 'ember-babel');
+        });
+      },
+    };
+  }
+
+  injectBabelHelpersPlugin.baseDir = function() {
+    return 'babel-core';
+  };
+
+  return injectBabelHelpersPlugin;
+}
+
+module.exports = injectBabelHelpers;

package.json

@@ -48,6 +48,7 @@
     "test:browserstack": "node bin/run-browserstack-tests.js"
   },
   "dependencies": {
+    "@babel/helper-module-imports": "^7.0.0",
     "@babel/plugin-transform-block-scoping": "^7.4.4",
     "@babel/plugin-transform-object-assign": "^7.2.0",
     "babel-plugin-debug-macros": "^0.3.2",
@@ -70,7 +71,6 @@
     "silent-error": "^1.1.1"
   },
   "devDependencies": {
-    "@babel/helper-module-imports": "^7.0.0",
     "@babel/preset-env": "^7.5.5",
     "@glimmer/compiler": "0.38.5-alpha.2",
     "@glimmer/env": "^0.1.7",