addressing comments

packages/core/src/app.ts

@@ -393,7 +393,7 @@ export class AppBuilder<TreeNames> {
     ]);
 
     // this is @embroider/macros configured for full stage3 resolution
-    babel.plugins.push(this.macrosConfig.babelPluginConfig());
+    babel.plugins = babel.plugins.concat(this.macrosConfig.babelPluginConfig());
 
     babel.plugins.push([require.resolve('./template-colocation-plugin')]);
 

packages/macros/package.json

@@ -27,6 +27,7 @@
     "@embroider/shared-internals": "0.43.4",
     "assert-never": "^1.2.1",
     "ember-cli-babel": "^7.26.6",
+    "find-up": "^5.0.0",
     "lodash": "^4.17.21",
     "resolve": "^1.20.0",
     "semver": "^7.3.2"

packages/macros/src/ember-addon-main.ts

@@ -1,6 +1,4 @@
-import fs from 'fs';
 import { join } from 'path';
-import crypto from 'crypto';
 import { MacrosConfig, isEmbroiderMacrosPlugin } from './node';
 
 export = {
@@ -71,38 +69,7 @@ export = {
     if (!babelPlugins.some(isEmbroiderMacrosPlugin)) {
       let appInstance = this._findHost();
       let source = appOrAddonInstance.root || appOrAddonInstance.project.root;
-      babelPlugins.unshift(MacrosConfig.for(appInstance).babelPluginConfig(source));
-
-      let yarnLockPath = join(appInstance.project.root, 'yarn.lock');
-      let npmLockPath = join(appInstance.project.root, 'package-lock.json');
-      let pnpmLockPath = join(appInstance.project.root, 'pnpm-lock.yaml');
-      let packagePath = join(appInstance.project.root, 'package.json');
-      let lockFileBuffer;
-
-      if (fs.existsSync(yarnLockPath)) {
-        lockFileBuffer = fs.readFileSync(yarnLockPath);
-      } else if (fs.existsSync(npmLockPath)) {
-        lockFileBuffer = fs.readFileSync(npmLockPath);
-      } else if (fs.existsSync(pnpmLockPath)) {
-        lockFileBuffer = fs.readFileSync(pnpmLockPath);
-      } else {
-        // no lock file found, using package.json as a fall back
-        lockFileBuffer = fs.readFileSync(packagePath);
-      }
-
-      // @embroider/macros provides a macro called dependencySatisfies which checks if a given
-      // package name satisfies a given semver version range. Due to the way babel caches this can
-      // cause a problem where the macro plugin does not run (because it has been cached) but the version
-      // of the dependency being checked for changes (due to installing a different version). This will lead to
-      // the old evaluated state being used which might be invalid. This cache busting plugin keeps track of a
-      // hash representing the lock file of the app and if it ever changes forces babel to rerun its plugins.
-      // more information in issue #906
-      let cacheKey = crypto.createHash('sha256').update(lockFileBuffer).digest('hex');
-      babelPlugins.push([
-        require.resolve('@embroider/shared-internals/src/babel-plugin-cache-busting.js'),
-        { version: cacheKey },
-        '@embroider/macros cache buster',
-      ]);
+      babelOptions.plugins = babelPlugins.concat(MacrosConfig.for(appInstance).babelPluginConfig(source));
     }
   },
 

packages/macros/src/macros-config.ts

@@ -1,4 +1,7 @@
+import fs from 'fs';
 import { join } from 'path';
+import crypto from 'crypto';
+import findUp from 'find-up';
 import type { PluginItem } from '@babel/core';
 import { PackageCache, getOrCreate } from '@embroider/shared-internals';
 import { makeFirstTransform, makeSecondTransform } from './glimmer/ast-transform';
@@ -255,7 +258,7 @@ export default class MacrosConfig {
   // normal node_modules resolution can find their dependencies. In other words,
   // owningPackageRoot is needed when you use this inside classic ember-cli, and
   // it's not appropriate inside embroider.
-  babelPluginConfig(owningPackageRoot?: string): PluginItem {
+  babelPluginConfig(owningPackageRoot?: string): PluginItem[] {
     let self = this;
     let opts: State['opts'] = {
       // this is deliberately lazy because we want to allow everyone to finish
@@ -281,7 +284,31 @@ export default class MacrosConfig {
 
       importSyncImplementation: this.importSyncImplementation,
     };
-    return [join(__dirname, 'babel', 'macros-babel-plugin.js'), opts];
+
+    let lockFilePath = findUp.sync(['yarn.lock', 'package-lock.json', 'pnpm-lock.yaml']);
+
+    if (!lockFilePath) {
+      lockFilePath = findUp.sync('package.json');
+    }
+
+    let lockFileBuffer = lockFilePath ? fs.readFileSync(lockFilePath) : 'no-cache-key';
+
+    // @embroider/macros provides a macro called dependencySatisfies which checks if a given
+    // package name satisfies a given semver version range. Due to the way babel caches this can
+    // cause a problem where the macro plugin does not run (because it has been cached) but the version
+    // of the dependency being checked for changes (due to installing a different version). This will lead to
+    // the old evaluated state being used which might be invalid. This cache busting plugin keeps track of a
+    // hash representing the lock file of the app and if it ever changes forces babel to rerun its plugins.
+    // more information in issue #906
+    let cacheKey = crypto.createHash('sha256').update(lockFileBuffer).digest('hex');
+    return [
+      [join(__dirname, 'babel', 'macros-babel-plugin.js'), opts],
+      [
+        require.resolve('@embroider/shared-internals/src/babel-plugin-cache-busting.js'),
+        { version: cacheKey },
+        `@embroider/macros cache buster: ${owningPackageRoot}`,
+      ],
+    ];
   }
 
   static astPlugins(owningPackageRoot?: string): {

packages/macros/tests/babel/helpers.ts

@@ -54,7 +54,7 @@ export function makeBabelConfig(_babelVersion: number, macroConfig: MacrosConfig
   return {
     filename: join(__dirname, 'sample.js'),
     presets: [],
-    plugins: [macroConfig.babelPluginConfig()],
+    plugins: macroConfig.babelPluginConfig(),
   };
 }
 
@@ -100,7 +100,7 @@ export function allBabelVersions(createTests: CreateTests | CreateTestsWithConfi
       return {
         filename: join(__dirname, 'sample.js'),
         presets: [],
-        plugins: [config.babelPluginConfig()],
+        plugins: config.babelPluginConfig(),
       };
     },
 

tests/scenarios/macro-test.ts

@@ -7,6 +7,17 @@ import { loadFromFixtureData } from './helpers';
 import fs from 'fs-extra';
 const { module: Qmodule, test } = QUnit;
 
+function updateLodashVersion(app: PreparedApp, version: string) {
+  let pkgJson = fs.readJsonSync(join(app.dir, 'package.json'));
+  let pkgJsonLodash = fs.readJsonSync(join(app.dir, 'node_modules', 'lodash', 'package.json'));
+
+  pkgJson.devDependencies.lodash = version;
+  pkgJsonLodash.version = version;
+
+  fs.writeJsonSync(join(app.dir, 'package.json'), pkgJson);
+  fs.writeJsonSync(join(app.dir, 'node_modules', 'lodash', 'package.json'), pkgJsonLodash);
+}
+
 appScenarios
   .map('macro-tests', project => {
     let macroSampleAddon = Project.fromDir(dirname(require.resolve('../addon-template/package.json')), {
@@ -36,8 +47,12 @@ appScenarios
   .forEachScenario(scenario => {
     Qmodule(scenario.name, function (hooks) {
       let app: PreparedApp;
+      let pkgJson: any;
+      let pkgJsonLodash: any;
+
       hooks.before(async () => {
         app = await scenario.prepare();
+        updateLodashVersion(app, '4.0.0');
       });
 
       test(`yarn test`, async function (assert) {
@@ -56,27 +71,30 @@ appScenarios
         assert.equal(result.exitCode, 0, result.output);
       });
 
-      test(`multiple dependency check`, async function (assert) {
-        let pkgJson = fs.readJsonSync(join(app.dir, 'package.json'));
-        let pkgJsonLodash = fs.readJsonSync(join(app.dir, 'node_modules', 'lodash', 'package.json'));
+      test(`@embroider/macros babel caching plugin works`, async function (assert) {
+        let lodashFourRun = await app.execute(`yarn test`);
+        assert.equal(lodashFourRun.exitCode, 0, lodashFourRun.output);
 
-        pkgJson.devDependencies.lodash = '4.0.0';
-        pkgJsonLodash.version = '4.0.0';
+        // simulate a different version being installed
+        updateLodashVersion(app, '3.0.0');
 
-        fs.writeJsonSync(join(app.dir, 'package.json'), pkgJson);
-        fs.writeJsonSync(join(app.dir, 'node_modules', 'lodash', 'package.json'), pkgJsonLodash);
+        let lodashThreeRun = await app.execute(`cross-env LODASH_VERSION=three yarn test`);
+        assert.equal(lodashThreeRun.exitCode, 0, lodashThreeRun.output);
+      });
 
-        let lodashFourRun = await app.execute(`yarn test`);
+      test(`CLASSIC=true @embroider/macros babel caching plugin works`, async function (assert) {
+        updateLodashVersion(app, '4.0.1');
+
+        let lodashFourRun = await app.execute(`cross-env CLASSIC=true yarn test`);
         assert.equal(lodashFourRun.exitCode, 0, lodashFourRun.output);
 
-        // downgrade lodash to 3.0.0
-        pkgJson.devDependencies.lodash = '3.0.0';
-        pkgJsonLodash.version = '3.0.0';
+        // simulate a different version being installed
+        updateLodashVersion(app, '3.0.0');
 
         fs.writeJsonSync(join(app.dir, 'package.json'), pkgJson);
         fs.writeJsonSync(join(app.dir, 'node_modules', 'lodash', 'package.json'), pkgJsonLodash);
 
-        let lodashThreeRun = await app.execute(`cross-env LODASH_VERSION=three yarn test`);
+        let lodashThreeRun = await app.execute(`cross-env LODASH_VERSION=three CLASSIC=true yarn test`);
         assert.equal(lodashThreeRun.exitCode, 0, lodashThreeRun.output);
       });
     });