pdfjs-dist fails to compile with Turbopack (webpackIgnore comment not respected)

[timneutkens]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/pdf-viewer-forked-h3gdsc?file=%2Fcomponents%2FTestPage.tsx

To Reproduce

1. Open https://codesandbox.io/p/devbox/pdf-viewer-forked-h3gdsc?file=%2Fcomponents%2FTestPage.tsx
2. Observe the compilation failing with Module not found (example: https://h3gdsc-3000.csb.app/)

Current vs. Expected behavior

pdfjs-dist ships with a webpack specific ignore comment (:til: that is a feature) as they use import() to load a file based on an option being passed in.

Specifically const worker = await import(/* webpackIgnore: true */ this.workerSrc); fails to compile as it can't find this.workerSrc statically.

I'm not sure what the best behavior is for this, adding support for the comment or ignoring such imports when they don't include a path.

Provide environment information

Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP PREEMPT_DYNAMIC Sun Aug  6 20:05:33 UTC 2023
  Available memory (MB): 4102
  Available CPU cores: 2
Binaries:
  Node: 20.12.0
  npm: 10.5.0
  Yarn: 1.22.19
  pnpm: 8.15.6
Relevant Packages:
  next: 14.3.0-canary.40 // Latest available version is detected (14.3.0-canary.40).
  eslint-config-next: 14.1.0
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.3.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Turbopack

Which stage(s) are affected? (Select all that apply)

next dev (local), next build (local), next start (local), Vercel (Deployed), Other (Deployed)

Additional context

This is failing on all versions with Turbopack as it doesn't support the ignore comment.

_PACK-3046

[timneutkens]

This issue came out of #63385 (comment)

[timneutkens]

@enricoros adding screenshots of CLI output is not helpful in general. If you want to share that you're running into the same issue you can use GitHub's emoji reactions on the initial post to add a 👍

Thanks!

[husseinraoouf]

@timneutkens this is the only thing preventing me from using turbopack with next dev now, shouldn't we add a test for the webpackIgnore case in general to make sure turbo have 100% compatibility with current webpack setup in nextjs and to better to show in the areweturboyet.com

[dmkotan]

Used bun patch for a workaround. patch-package should work too.

diff --git a/build/pdf.mjs b/build/pdf.mjs
--- a/build/pdf.mjs
+++ b/build/pdf.mjs
@@ -11936,7 +11936,8 @@ class PDFWorker {
       if (this.#mainThreadWorkerMessageHandler) {
         return this.#mainThreadWorkerMessageHandler;
       }
-      const worker = await import( /*webpackIgnore: true*/this.workerSrc);
+      // https://github.com/vercel/next.js/issues/65406
+      const worker = await import( /*webpackIgnore: true*/this.workerSrc ?? "./pdf.worker.mjs");
       return worker.WorkerMessageHandler;
     };
     return shadow(this, "_setupFakeWorkerGlobal", loader());

[gurkerl83]

It seems Vercel has made progress in handling Workers within Turbopack. As of Next.js 15.0.0-canary.148, the previously reported error has been resolved. This error was still present in canary.146, but no longer appears in the latest canary release.

Thx!

[timneutkens]

Thanks for checking @gurkerl83 this issue has indeed been resolved, we added support for webpackIgnore and turbopackIgnore and it's available on next@canary, will be in Next.js 15 RC.2 soon!

Related PR: #69768

[github-actions]

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