optimizeDeps.exclude removes default property from exports

[sagargurtu]

Describe the bug

When a dependency is added in optimizeDeps.exclude, it injects __reExport during dependency pre-bundling (link) which removes default property.

Steps to reproduce:

• Copy the project from https://stackblitz.com/edit/vitejs-vite-u5bre3 to a local dev environment since StackBlitz doesn't show node_modules/ directory.
• The vite configuration is doing two things:
  • Excluding react from optimizeDeps.
  • Declaring a plugin that marks react imports as external and replaces them with external ESM URLs.
• Start dev server and open the URL. It throws error in browser console.
• Search node_modules/.vite/deps for a chunk file that contains // external:react. It has the following code snippet:

  // external:react
  var react_exports = {};
  import * as react_star from "react";
  var init_react = __esm({
    "external:react"() {
      __reExport(react_exports, react_star);
    }
  });
  

• __reExport removes default property from react import:

  var __reExport = (target, mod, secondTarget) => (__copyProps(target, mod, "default"), secondTarget && __copyProps(secondTarget, mod, "default"));
  

• Comment out lines 7-12 (both inclusive) in src/index.tsx. Refresh the webpage, it loads the UI without error.
• Alternatively, comment out optimizeDeps and plugin implementation from vite config. Refresh the webpage, it loads the UI without error.
• Issue: theming.esm.js is trying to access React.Component but it is undefined because react_exports does not contain "default" property.

Reproduction

https://stackblitz.com/edit/vitejs-vite-u5bre3

System Info

System:
  OS: Linux 5.0 undefined
  CPU: (4) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
  Memory: 0 Bytes / 0 Bytes
  Shell: 1.0 - /bin/jsh
Binaries:
  Node: 16.14.2 - /usr/local/bin/node
  Yarn: 1.22.10 - /usr/local/bin/yarn
  npm: 7.17.0 - /usr/local/bin/npm
npmPackages:
  @vitejs/plugin-react: ^2.1.0 => 2.1.0 
  vite: ^3.1.3 => 3.1.3

Used Package Manager

npm

Logs

Console Error:

Uncaught TypeError: Cannot read properties of undefined (reading 'Component')
    at createThemeProvider (theming.js?v=288fcf31:403:27)
    at createTheming (theming.js?v=288fcf31:443:20)
    at theming.js?v=288fcf31:447:22

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• The provided reproduction is a minimal reproducible example of the bug.