The syntax export { default } from ... in vue file leads to Uncaught SyntaxError: Duplicate export of 'default'

[511581884]

Describe the bug

if you write export { default } from ... at script block in vue file, the result is:

• in dev, the broswer will tell you: Uncaught SyntaxError: Duplicate export of 'default'
• in prod, the terminal will tell you: [rollup-plugin-dynamic-import-variables] Duplicate export 'default'

index.ts

import { ref } from 'vue';
export default {
  setup() {
    const count = ref(1);
    return {
      count,
    };
  },
};

index.vue

<template>
  <h1>{{ count }}</h1>
</template>

<script>
export { default } from './index';
</script>

<style ></style>

if you run npm run dev, the browser shows:

if you run npm run build, the terminal shows:

If I write a plugin to transform all export {default} from ... into import xxx from xxx; export default xxx, then vite works corretcly.
Or if I change the following source code about genScriptCode in plugin-vue/src/main.ts, just add a judgement condition, it also works corretcly.

It seems that the problem is in the @vitejs/plugin-vue, the above syntax is not considered in this plugin.

Reproduction

https://stackblitz.com/edit/vitejs-vite-d9ekar?file=src/components/HelloWorld.vue

System Info

System:
    OS: Windows 10 10.0.19042
    CPU: (8) x64 Intel(R) Core(TM) i5-8300H CPU @ 2.30GHz
    Memory: 1.08 GB / 7.86 GB
Binaries:
    Node: 14.17.3 - D:\app\nodejs\node.EXE
    Yarn: 1.22.10 - D:\app\nodejs\node_global\yarn.CMD
    npm: 6.14.13 - D:\app\nodejs\npm.CMD
Browsers:
    Edge: Spartan (44.19041.1266.0), Chromium (101.0.1210.32), ChromiumDev

Used Package Manager

npm

Logs

[rollup-plugin-dynamic-import-variables] Duplicate export 'default' (13:7)
file: E:/project/vite-vue3-ts-example/src/components/HelloWorld.vue:13:7
error during build:
SyntaxError: Duplicate export 'default' (13:7)
    at Parser.pp$4.raise (E:\project\vite-vue3-ts-example\node_modules\_rollup@2.71.1@rollup\dist\shared\rollup.js:19704:13)
    at Parser.pp$8.checkExport (E:\project\vite-vue3-ts-example\node_modules\_rollup@2.71.1@rollup\dist\shared\rollup.js:17958:12)
    at Parser.pp$8.parseExport (E:\project\vite-vue3-ts-example\node_modules\_rollup@2.71.1@rollup\dist\shared\rollup.js:17901:10)
    at Parser.pp$8.parseStatement (E:\project\vite-vue3-ts-example\node_modules\_rollup@2.71.1@rollup\dist\shared\rollup.js:17174:74)
    at Parser.pp$8.parseTopLevel (E:\project\vite-vue3-ts-example\node_modules\_rollup@2.71.1@rollup\dist\shared\rollup.js:17055:21)
    at Parser.parse (E:\project\vite-vue3-ts-example\node_modules\_rollup@2.71.1@rollup\dist\shared\rollup.js:16827:15)
    at Function.parse (E:\project\vite-vue3-ts-example\node_modules\_rollup@2.71.1@rollup\dist\shared\rollup.js:16877:35)
    at Graph.contextParse (E:\project\vite-vue3-ts-example\node_modules\_rollup@2.71.1@rollup\dist\shared\rollup.js:22981:38)
    at Object.transform (E:\project\vite-vue3-ts-example\node_modules\_vite@2.9.7@vite\dist\node\chunks\dep-88bd5805.js:19769:27)
    at E:\project\vite-vue3-ts-example\node_modules\_rollup@2.71.1@rollup\dist\shared\rollup.js:22834:37
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! create@0.0.0 build: `vite build --debug`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the create@0.0.0 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to https://github.com/vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[sapphi-red]

Closing as it is fixed by vuejs/core#5937 which is released on Vue 3.2.34.