fix: disable lazy barrel in bundled dev

Author: mturac

packages/vite/src/node/server/bundledDev.ts

@@ -353,6 +353,9 @@ export class BundledDev {
         this.environment.getTopLevelConfig(),
       ),
     }
+    // disable lazy barrel optimization due to a bug in Rolldown dev mode
+    // https://github.com/vitejs/vite/issues/22749
+    rolldownOptions.experimental.lazyBarrel = false
 
     // disable inlineConst optimization due to a bug in Rolldown
     // https://github.com/vitejs/vite/issues/21843

playground/bundled-dev/__tests__/bundled-dev.spec.ts

@@ -0,0 +1,23 @@
+import { expect, test } from 'vitest'
+import { isBuild, page } from '~utils'
+
+if (isBuild) {
+  test('should render', async () => {
+    await expect.poll(() => page.textContent('.app')).toBe('hello')
+    await expect
+      .poll(() => page.textContent('.date-fns-locale'))
+      .toBe('czerwca')
+  })
+} else {
+  test('bundles locale barrel imports', async () => {
+    const reloadPromise = page.waitForEvent('load')
+    await expect
+      .poll(() => page.textContent('body'))
+      .toContain('Bundling in progress')
+    await reloadPromise
+    await expect.poll(() => page.textContent('.app')).toBe('hello')
+    await expect
+      .poll(() => page.textContent('.date-fns-locale'))
+      .toBe('czerwca')
+  })
+}

playground/bundled-dev/index.html

@@ -0,0 +1,4 @@
+<div class="app"></div>
+<div class="date-fns-locale"></div>
+
+<script type="module" src="./main.js"></script>

playground/bundled-dev/main.js

@@ -0,0 +1,9 @@
+import { format } from 'date-fns'
+import { pl } from 'date-fns/locale'
+
+text('.app', 'hello')
+text('.date-fns-locale', format(new Date(2020, 5, 1), 'MMMM', { locale: pl }))
+
+function text(el, text) {
+  document.querySelector(el).textContent = text
+}

playground/bundled-dev/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "@vitejs/test-bundled-dev",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "dependencies": {
+    "date-fns": "4.1.0"
+  },
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "preview": "vite preview"
+  }
+}

playground/bundled-dev/vite.config.ts

@@ -0,0 +1,48 @@
+import { type Plugin, defineConfig } from 'vite'
+
+export default defineConfig({
+  experimental: {
+    bundledDev: true,
+  },
+  plugins: [waitBundleCompleteUntilAccess()],
+})
+
+function waitBundleCompleteUntilAccess(): Plugin {
+  let resolvers: PromiseWithResolvers<void>
+
+  return {
+    name: 'wait-bundle-complete-until-access',
+    apply: 'serve',
+    configureServer(server) {
+      let accessCount = 0
+      resolvers = promiseWithResolvers()
+
+      server.middlewares.use((_req, _res, next) => {
+        accessCount++
+        if (accessCount === 1) {
+          resolvers.resolve()
+        }
+        next()
+      })
+    },
+    async generateBundle() {
+      await resolvers.promise
+    },
+  }
+}
+
+interface PromiseWithResolvers<T> {
+  promise: Promise<T>
+  resolve: (value: T | PromiseLike<T>) => void
+  reject: (reason?: any) => void
+}
+
+function promiseWithResolvers<T>(): PromiseWithResolvers<T> {
+  let resolve: any
+  let reject: any
+  const promise = new Promise<T>((_resolve, _reject) => {
+    resolve = _resolve
+    reject = _reject
+  })
+  return { promise, resolve, reject }
+}