fix(legacy): fix broken build when renderModernChunks=false & polyfills=false (fix #14324)

packages/plugin-legacy/src/index.ts

@@ -258,34 +258,34 @@ function viteLegacyPlugin(options: Options = {}): Plugin[] {
       }
 
       // legacy bundle
-      if (legacyPolyfills.size) {
+      if (options.polyfills !== false) {
         // check if the target needs Promise polyfill because SystemJS relies on it
         // https://github.com/systemjs/systemjs#ie11-support
         await detectPolyfills(
           `Promise.resolve(); Promise.all();`,
           targets,
           legacyPolyfills,
         )
+      }
 
-        isDebug &&
-          console.log(
-            `[@vitejs/plugin-legacy] legacy polyfills:`,
-            legacyPolyfills,
-          )
-
-        await buildPolyfillChunk(
-          config.mode,
+      isDebug &&
+        console.log(
+          `[@vitejs/plugin-legacy] legacy polyfills:`,
           legacyPolyfills,
-          bundle,
-          facadeToLegacyPolyfillMap,
-          // force using terser for legacy polyfill minification, since esbuild
-          // isn't legacy-safe
-          config.build,
-          'iife',
-          opts,
-          options.externalSystemJS,
         )
-      }
+
+      await buildPolyfillChunk(
+        config.mode,
+        legacyPolyfills,
+        bundle,
+        facadeToLegacyPolyfillMap,
+        // force using terser for legacy polyfill minification, since esbuild
+        // isn't legacy-safe
+        config.build,
+        'iife',
+        opts,
+        options.externalSystemJS,
+      )
     },
   }
 

playground/legacy/__tests__/no-polyfills/no-polyfills.spec.ts

@@ -0,0 +1,20 @@
+import { test } from 'vitest'
+import { isBuild, page, untilUpdated, viteTestUrl } from '~utils'
+
+test('should load and execute the JS file', async () => {
+  await page.goto(viteTestUrl + '/no-polyfills.html')
+  await untilUpdated(() => page.textContent('main'), '👋', true)
+})
+
+test.runIf(isBuild)('includes a script tag for SystemJS', async () => {
+  await untilUpdated(
+    () => page.getAttribute('#vite-legacy-polyfill', 'src'),
+    /.\/assets\/polyfills-legacy-(.+)\.js/,
+    true,
+  )
+  await untilUpdated(
+    () => page.getAttribute('#vite-legacy-entry', 'data-src'),
+    /.\/assets\/index-legacy-(.+)\.js/,
+    true,
+  )
+})

playground/legacy/no-polyfills.html

@@ -0,0 +1,3 @@
+<meta charset="UTF-8" />
+<main></main>
+<script type="module" src="./no-polyfills.js"></script>

playground/legacy/no-polyfills.js

@@ -0,0 +1 @@
+document.querySelector('main').innerHTML = '👋'

playground/legacy/package.json

@@ -8,6 +8,7 @@
     "build": "vite build --debug legacy",
     "build:custom-filename": "vite --config ./vite.config-custom-filename.js build  --debug legacy",
     "build:multiple-output": "vite --config ./vite.config-multiple-output.js build",
+    "build:no-polyfills": "vite --config ./vite.config-no-polyfills.js build",
     "debug": "node --inspect-brk ../../packages/vite/bin/vite",
     "preview": "vite preview"
   },

playground/legacy/vite.config-no-polyfills.js

@@ -0,0 +1,29 @@
+import path from 'node:path'
+import legacy from '@vitejs/plugin-legacy'
+import { defineConfig } from 'vite'
+
+export default defineConfig({
+  base: './',
+  plugins: [
+    legacy({
+      renderModernChunks: false,
+      polyfills: false,
+    }),
+    {
+      name: 'remove crossorigin attribute',
+      transformIndexHtml: (html) => html.replaceAll('crossorigin', ''),
+      enforce: 'post',
+    },
+  ],
+
+  build: {
+    rollupOptions: {
+      input: {
+        index: path.resolve(__dirname, 'no-polyfills.html'),
+      },
+    },
+  },
+  testConfig: {
+    baseRoute: '/no-polyfills/',
+  },
+})