Works in Dev, Not in Prod - imported module has undefined exports

[KevinBrogan]

Describe the bug

I am importing a package that has been installed via npm.
Development works fine
The package imports are undefined in production

Reproduction

https://stackblitz.com/edit/vitejs-vite-vtgp1g?file=main.js

Steps to reproduce

vite build
vite preview

check console in preview window and see that the logged module is empty
Note how dev had the module contents

System Info

stackblitz

❯ npx envinfo --system --npmPackages '{vite,@vitejs/*}' --binaries --browsers
success Install finished in 1.074s

  System:
    OS: Linux 5.0 undefined
    CPU: (8) 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: 1.22.19 - /usr/local/bin/yarn
    npm: 7.17.0 - /usr/local/bin/npm
  npmPackages:
    vite: ^3.1.8 => 3.1.8

Used Package Manager

npm

Logs

Click to expand!

❯ vite build --debug
  vite:config no config file found. +0ms
  vite:esbuild init tsconfck (root: /home/projects/vitejs-vite-vtgp1g) +0ms
  vite:esbuild init tsconfck (root: /home/projects/vitejs-vite-vtgp1g) +1ms
  vite:esbuild init tsconfck (root: /home/projects/vitejs-vite-vtgp1g) +1ms
  vite:esbuild init tsconfck (root: /home/projects/vitejs-vite-vtgp1g) +0ms
  vite:esbuild init tsconfck end +2ms
  vite:esbuild init tsconfck end +0ms
  vite:esbuild init tsconfck end +0ms
  vite:esbuild init tsconfck end +0ms
  vite:config using resolved config: {
  vite:config   root: '/home/projects/vitejs-vite-vtgp1g',
  vite:config   base: '/',
  vite:config   mode: 'production',
  vite:config   configFile: undefined,
  vite:config   logLevel: undefined,
  vite:config   clearScreen: undefined,
  vite:config   optimizeDeps: {
  vite:config     disabled: 'build',
  vite:config     force: undefined,
  vite:config     esbuildOptions: { preserveSymlinks: undefined }
  vite:config   },
  vite:config   build: {
  vite:config     target: [ 'es2020', 'edge88', 'firefox78', 'chrome87', 'safari13' ],
  vite:config     polyfillModulePreload: true,
  vite:config     outDir: 'dist',
  vite:config     assetsDir: 'assets',
  vite:config     assetsInlineLimit: 4096,
  vite:config     cssCodeSplit: true,
  vite:config     cssTarget: [ 'es2020', 'edge88', 'firefox78', 'chrome87', 'safari13' ],
  vite:config     sourcemap: false,
  vite:config     rollupOptions: {},
  vite:config     minify: 'esbuild',
  vite:config     terserOptions: {},
  vite:config     write: true,
  vite:config     emptyOutDir: null,
  vite:config     manifest: false,
  vite:config     lib: false,
  vite:config     ssr: false,
  vite:config     ssrManifest: false,
  vite:config     reportCompressedSize: true,
  vite:config     chunkSizeWarningLimit: 500,
  vite:config     watch: null,
  vite:config     commonjsOptions: { include: [Array], extensions: [Array] },
  vite:config     dynamicImportVarsOptions: { warnOnError: true, exclude: [Array] }
  vite:config   },
  vite:config   configFileDependencies: [],
  vite:config   inlineConfig: {
  vite:config     root: undefined,
  vite:config     base: undefined,
  vite:config     mode: undefined,
  vite:config     configFile: undefined,
  vite:config     logLevel: undefined,
  vite:config     clearScreen: undefined,
  vite:config     optimizeDeps: { force: undefined },
  vite:config     build: {}
  vite:config   },
  vite:config   resolve: { alias: [ [Object], [Object] ] },
  vite:config   publicDir: '/home/projects/vitejs-vite-vtgp1g/public',
  vite:config   cacheDir: '/home/projects/vitejs-vite-vtgp1g/node_modules/.vite',
  vite:config   command: 'build',
  vite:config   ssr: {
  vite:config     format: 'esm',
  vite:config     target: 'node',
  vite:config     optimizeDeps: { disabled: true, esbuildOptions: [Object] }
  vite:config   },
  vite:config   isWorker: false,
  vite:config   mainConfig: null,
  vite:config   isProduction: true,
  vite:config   plugins: [
  vite:config     'vite:build-metadata',
  vite:config     'vite:pre-alias',
  vite:config     'alias',
  vite:config     'vite:modulepreload-polyfill',
  vite:config     'vite:resolve',
  vite:config     'vite:html-inline-proxy',
  vite:config     'vite:css',
  vite:config     'vite:esbuild',
  vite:config     'vite:json',
  vite:config     'vite:wasm-helper',
  vite:config     'vite:worker',
  vite:config     'vite:asset',
  vite:config     'vite:wasm-fallback',
  vite:config     'vite:define',
  vite:config     'vite:css-post',
  vite:config     'vite:build-html',
  vite:config     'vite:worker-import-meta-url',
  vite:config     'vite:force-systemjs-wrap-complete',
  vite:config     'vite:watch-package-data',
  vite:config     'commonjs',
  vite:config     'vite:data-uri',
  vite:config     'vite:asset-import-meta-url',
  vite:config     'vite:dynamic-import-vars',
  vite:config     'vite:import-glob',
  vite:config     'vite:build-import-analysis',
  vite:config     'vite:esbuild-transpile',
  vite:config     'vite:terser',
  vite:config     'vite:reporter',
  vite:config     'vite:load-fallback'
  vite:config   ],
  vite:config   server: {
  vite:config     preTransformRequests: true,
  vite:config     middlewareMode: false,
  vite:config     fs: { strict: true, allow: [Array], deny: [Array] }
  vite:config   },
  vite:config   preview: {
  vite:config     port: undefined,
  vite:config     strictPort: undefined,
  vite:config     host: undefined,
  vite:config     https: undefined,
  vite:config     open: undefined,
  vite:config     proxy: undefined,
  vite:config     cors: undefined,
  vite:config     headers: undefined
  vite:config   },
  vite:config   env: { BASE_URL: '/', MODE: 'production', DEV: false, PROD: true },
  vite:config   assetsInclude: [Function: assetsInclude],
  vite:config   logger: {
  vite:config     hasWarned: false,
  vite:config     info: [Function: info],
  vite:config     warn: [Function: warn],
  vite:config     warnOnce: [Function: warnOnce],
  vite:config     error: [Function: error],
  vite:config     clearScreen: [Function: clearScreen],
  vite:config     hasErrorLogged: [Function: hasErrorLogged]
  vite:config   },
  vite:config   packageCache: Map(0) { set: [Function (anonymous)] },
  vite:config   createResolver: [Function: createResolver],
  vite:config   worker: {
  vite:config     format: 'iife',
  vite:config     plugins: [
  vite:config       'vite:build-metadata',
  vite:config       'vite:pre-alias',
  vite:config       'alias',
  vite:config       'vite:modulepreload-polyfill',
  vite:config       'vite:resolve',
  vite:config       'vite:html-inline-proxy',
  vite:config       'vite:css',
  vite:config       'vite:esbuild',
  vite:config       'vite:json',
  vite:config       'vite:wasm-helper',
  vite:config       'vite:worker',
  vite:config       'vite:asset',
  vite:config       'vite:wasm-fallback',
  vite:config       'vite:define',
  vite:config       'vite:css-post',
  vite:config       'vite:build-html',
  vite:config       'vite:worker-import-meta-url',
  vite:config       'vite:force-systemjs-wrap-complete',
  vite:config       'vite:watch-package-data',
  vite:config       'commonjs',
  vite:config       'vite:data-uri',
  vite:config       'vite:asset-import-meta-url',
  vite:config       'vite:dynamic-import-vars',
  vite:config       'vite:import-glob',
  vite:config       'vite:build-import-analysis',
  vite:config       'vite:esbuild-transpile',
  vite:config       'vite:terser',
  vite:config       'vite:reporter',
  vite:config       'vite:load-fallback'
  vite:config     ],
  vite:config     rollupOptions: {},
  vite:config     getSortedPlugins: [Function: getSortedPlugins],
  vite:config     getSortedPluginHooks: [Function: getSortedPluginHooks]
  vite:config   },
  vite:config   appType: 'spa',
  vite:config   experimental: { importGlobRestoreExtension: false, hmrPartialAccept: false },
  vite:config   getSortedPlugins: [Function: getSortedPlugins],
  vite:config   getSortedPluginHooks: [Function: getSortedPluginHooks]
  vite:config } +10ms
vite v3.1.8 building for production...
✓ 9 modules transformed.
dist/index.html                 0.22 KiB
dist/assets/index.150a79b3.js   3.18 KiB / gzip: 1.60 KiB

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[Tanimodori]

Checkek out https://stackblitz.com/edit/vitejs-vite-nlwsq9?file=vite.config.js

The old siphash has something incompatible with bundlers here:

node_modules\siphash\lib\siphash.js

var SipHash = (function () {
    // ...
    return {
        hash: hash,
        hash_hex: hash_hex,
        hash_uint: hash_uint,
        string16_to_key: string16_to_key,
        string_to_u8: string_to_u8
    };
})();
var module = module || {}, exports = module.exports = SipHash;

The var module = module || {}, here is problematic, which let the bundlers to think that module is a regular variable rather than module exports. Remove the line results in successful build. You can use either rollup transform or patch-package to do the job.

vite.config.js

import { defineConfig } from "vite";

export default defineConfig({
  plugins: [
    {
      name: "fix-siphash-exports",
      transform(code, id) {
        const siphashRE = /node_modules\/siphash\/lib\/.*\.js$/;
        if(siphashRE.test(id)) {
          return code.replace("var module = module || {},", "");
        }
      }
    }
  ]
})

[bluwy]

I tried to fix what Tanimodori explained today. Ultimately, it introduces quite some complexity and given that it's a really edge case, I don't think this is worth fixing. The library should try to avoid the syntax, especially that module.exports directly would've already worked fine.

I'm going to close this as a wontfix, but if anyone is interested in fixing still, here's the rundown of where to fix it.

---

As shown, var module = module || {}, exports = module.exports = SipHash; causes an issue, where the second module is referring to the global module reference, however @rollup/plugin-commonjs wrongly analyzed that it's referring to var module.

This scope analysis is done here in @rollup/plugin-commonjs:

https://github.com/rollup/plugins/blob/4f9fc5a66eac9e6183ec2118caeadd57408a8f30/packages/commonjs/src/transform-commonjs.js#L294

The scope is created through its attachScopes util at:

https://github.com/rollup/plugins/blob/4f9fc5a66eac9e6183ec2118caeadd57408a8f30/packages/pluginutils/src/attachScopes.ts#L61

The utility assigns AST nodes that creates a scope with .scope. This is used by @rollup/plugin-commonjs. To fix this, you need to create another scope for the right-hand-side of var/let/const statements that excludes the variable name as part of the scope. HOWEVER, not for functions/classes in the right-hand side, they could have a different execution order.

// Example case

var module = module || (() => module)(); other()
//           |--------|
//         new scope here (A*)
//                     |--------------|
//                new scope but inherits from A (the existing code would take
//                A* which is incorrect, this needs to be specially handled)
// |-------------------------------------------|
//                parent scope (A)

A* is the new special scope we need to create. In practice, scopes don't really work like that? And it's kinda a special-case "scope" to only fix this issue. So altogether I didn't feel it's worth the effort.