Build fails after full package upgrade – “The symbol $i has already been declared”

[iolk]

Hi everyone,

I recently upgraded all the packages in my Vue codebase, carefully followed each migration guide, and fixed every TypeScript error. The dev server runs fine, but when I run a production build it consistently fails during chunk generation.

Here’s the output:

> vue-tsc --noEmit

> vite build

vite v7.1.5 building for production...
✓ 6757 modules transformed.
✗ Build failed in 39.37s
error during build:
[vite:esbuild-transpile] Transform failed with 1 error:
assets/index-!~{001}~.js:168011:22: ERROR: The symbol "$i" has already been declared
file: assets/index-!~{001}~.js:168011:22

The symbol "$i" has already been declared
168009 |    );
168010 |  }
168011 |  const Di = Pi(), [Ya, $i] = te("ConfigProvider");
       |                        ^
168012 |  let Bi = "useandom-26T198340PX75pxJACKVERYMINDBUSHWOLF_GQZbfghjklqvwyzrict", Ii = (a2 = 21) => {
168013 |    let t = "", e = a2;

This is my vite.config.mts

import tailwindcss from '@tailwindcss/vite'
import vue from '@vitejs/plugin-vue'
import path from 'path'
import friendlyTypeImports from 'rollup-plugin-friendly-type-imports'
import { defineConfig, loadEnv } from 'vite'
import mkcert from 'vite-plugin-mkcert'
import svgLoader from 'vite-svg-loader'

export default defineConfig(({ command, mode }) => {
  const env = loadEnv(mode, process.cwd(), '')

  return {
    define: {
      __APP_ENV__: env.APP_ENV,
    },
    plugins: [
      vue(),
      tailwindcss(),
      svgLoader(),
      friendlyTypeImports(),
      mkcert({
        hosts: ['*.local.test'],
      }),
    ],
    build: {
      sourcemap: false,
      manifest: true,
    },
    resolve: {
      alias: {
        '@': path.resolve(__dirname, './src'),
      },
      dedupe: ['vue'],
    },
    server: {
      host: '0.0.0.0',
      port: 3000,
    },
    preview: {
      port: 3000,
    },
  }
})

I can’t figure out where this duplicate declaration is coming from...
Has anyone encountered a similar issue or have suggestions on how to debug this?
Any help would be greatly appreciated!

Thanks in advance.

[vofronte]

Hi @iolk!

Looks like a minification conflict.

Try adding build: { minify: false } to your vite config. The error should then show the real variable name.

That ConfigProvider bit suggests it's your UI library. Which one you're using?

[fashion98]

Hello, this issue is actually caused by the upgrade of the plugin rollup referenced by Vite, rollup@4.50.1 This error will occur, and if it is @ 4.50.0 or earlier versions, it should be normal. You can try manually installing versions 4.50.0 or earlier to verify this issue. Because I have encountered the same problem as you. Vite should specify the dependent version based on its own version, which can prevent the upgrade of its dependent packages from causing problems that appear to be with the Vite version. Also, we need to wait for Rollup to release a patch version as soon as possible to fix this issue.

[iolk]

Thanks a lot for taking the time to help!

@vofronte your tip about disabling minification is super useful for debugging, I’ll remember that.

@fashion98 thanks for pointing out the Rollup version issue, it fixed the problem. I’ll lock it to 4.50.0 for now and watch for the patch release.

Really appreciate both of your suggestions!