Build fails when Web Worker dynamically imports module also dynamically imported by the main thread

[esturcke]

Describe the bug

I have created a Web Worker with type: module that dynamically imports a module shared with the main thread. In dev mode this works as expected, but when building I get (full logs below)

rendering chunks (2)...The emitted file "assets/logger.c9021ab8.js" overwrites a previously emitted file of the same name.
[vite:build-import-analysis] Cannot read property 'importedCss' of undefined

Reproduction

git clone https:/esturcke/web-worker-dynamic-import-error
cd web-worker-dynamic-import-error
yarn && yarn build

System Info

System:
    OS: macOS 12.5.1
    CPU: (10) x64 Apple M1 Pro
    Memory: 33.20 MB / 16.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 14.19.1 - ~/Library/Caches/fnm_multishells/39357_1662750145123/bin/node
    Yarn: 1.22.19 - /opt/homebrew/bin/yarn
    npm: 6.14.16 - ~/Library/Caches/fnm_multishells/39357_1662750145123/bin/npm
    Watchman: 2022.07.04.00 - /opt/homebrew/bin/watchman
  Browsers:
    Brave Browser: 102.1.39.122
    Chrome: 105.0.5195.102
    Chrome Canary: 107.0.5290.0
    Edge: 105.0.1343.33
    Firefox Developer Edition: 105.0
    Safari: 15.6.1
    Safari Technology Preview: 16.0
  npmPackages:
    vite: ^3.1.0 => 3.1.0

Used Package Manager

yarn

Logs

Click to expand!

❯ yarn build --debug     
yarn run v1.22.19
$ tsc && vite build --debug
  vite:config bundled config file loaded in 85.98ms +0ms
  vite:esbuild init tsconfck (root: /Users/esturcke/work/web-worker-dynamic-import-error) +0ms
  vite:esbuild init tsconfck (root: /Users/esturcke/work/web-worker-dynamic-import-error) +1ms
  vite:esbuild init tsconfck (root: /Users/esturcke/work/web-worker-dynamic-import-error) +1ms
  vite:esbuild init tsconfck (root: /Users/esturcke/work/web-worker-dynamic-import-error) +0ms
  vite:esbuild init tsconfck end +1ms
  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   worker: {
  vite:config     format: 'es',
  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   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   configFile: '/Users/esturcke/work/web-worker-dynamic-import-error/vite.config.ts',
  vite:config   configFileDependencies: [
  vite:config     '/Users/esturcke/work/web-worker-dynamic-import-error/vite.config.ts'
  vite:config   ],
  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   root: '/Users/esturcke/work/web-worker-dynamic-import-error',
  vite:config   base: '/',
  vite:config   resolve: { alias: [ [Object], [Object] ] },
  vite:config   publicDir: '/Users/esturcke/work/web-worker-dynamic-import-error/public',
  vite:config   cacheDir: '/Users/esturcke/work/web-worker-dynamic-import-error/node_modules/.vite',
  vite:config   command: 'build',
  vite:config   mode: 'production',
  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   appType: 'spa',
  vite:config   experimental: { importGlobRestoreExtension: false, hmrPartialAccept: false },
  vite:config   getSortedPlugins: [Function: getSortedPlugins],
  vite:config   getSortedPluginHooks: [Function: getSortedPluginHooks]
  vite:config } +13ms
vite v3.1.0 building for production...
✓ 2 modules transformed.
✓ 8 modules transformed.
rendering chunks (2)...The emitted file "assets/logger.c9021ab8.js" overwrites a previously emitted file of the same name.
[vite:build-import-analysis] Cannot read property 'importedCss' of undefined
error during build:
TypeError: Cannot read property 'importedCss' of undefined
    at addDeps (file:///Users/esturcke/work/web-worker-dynamic-import-error/node_modules/vite/dist/node/chunks/dep-665b0112.js:43002:60)
    at Object.generateBundle (file:///Users/esturcke/work/web-worker-dynamic-import-error/node_modules/vite/dist/node/chunks/dep-665b0112.js:43024:33)
    at file:///Users/esturcke/work/web-worker-dynamic-import-error/node_modules/rollup/dist/es/shared/rollup.js:22710:40
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

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• 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 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]

For a workaround, add a module that re-exports everything from logger.ts and use it instead in worker.

// logger2.ts
export * from './logger'

// worker.ts
onmessage = e => {
    import("./logger2").then(({ log }: any) => log(`worker: ${e.data}`)) // use logger2
}

export {}

[esturcke]

Thanks @sapphi-red, this looks like a nice workaround for direct imports. Unfortunately I ran into this while porting a project from Webpack to Vite and there are multiple dynamic imports brought in indirectly several levels deep. I'm not sure how feasible it will be to fork the entire call chain.

Update: I was able to get it to work with the workaround. Thanks!

[jedrichards]

Also struggling with this. In my case I'm not sure how to apply the workaround. My worker is a tiny wrapper around a class.

// Worker.ts
import { MyClass } from './MyClass'
import { expose } from 'comlink'
expose(MyClass)

MyClass is sometimes used within a worker, sometimes directly, depending on some settings.

Inside MyClass I make a dynamic import to a JS module, and since that is an implementation detail of MyClass, and not something I do directly in the worker, I'm not sure how to apply the workaround.

@esturcke It sounds similar to your case. Could you shed any light on your approach?

[shkreios]

Interestingly, when using worker that requires the vite react plugin both the main app & the worker i don't get any of these errors and just see that all the dependencies have been bundled twice. Once for the use inside the worker and once in the main thread.
This is the same result when using the workaround of reexporting the module suggested by @sapphi-red.

Even though this works, it increases the bundle size considerably in my case because both react and a large lib i.e. @react-pdf/renderer is getting bundled twice.