[Bug]: Playwright crashes WebWorker in a Chromium/FireFox "extension"

[44xtc44]

Version

1.57.0

Steps to reproduce

1. clone repository https://github.com/44xtc44/BUG-Playwright-fail-WebWorker-Extension
2. sudo su # remember your current user_name
   npm install -g n # to be able to downgrade the node version
   n 20 # to install the current max node.js version for playwright
   su user_name # back to last user env
   node -v # check version
3. npm install # see at least no warnings for playwright
4. Load the extension into Chromium to see it running properly. WebWorker sends a message.
5. Extension App, what we do:
   Have a web application extension/add-on with a few web workers that performs any actions.
   Configure "postMessage", "onmessage", "onerror".
   The WebWorker instance don't receive a message, only an empty error object.
6. Extension manifest.json Version 3
   Since Browser brands use different manifest syntax, copy from /tests/manifest/.
   Play around with the config. Perhaps this helps.
7. Test only one Browser brand with an extension!!! Needs the correct manifest.json file.
   import { chromium } from "playwright"; or import { chromium } from "playwright/test";
   or also tested:
   import { firefox } from "playwright"; or import { firefox } from "playwright/test";
8. run the function from test file in terminial /tests/end2end/

   npx run-func chromium.js homePageOpen -y

9. Please test the worker also with an imported module! If you got it working.

Expected behavior

I would expect to see a web worker message.

Actual behavior

I can not see a web worker message. Only an empty error object.

Additional context

Playwright FireFox (Nightly) test run shows the same error as Chromium.

To exclude the started Browser instance from failure start
firefox module via test module and keep the browser instance open.
Use the manifest from /tests/manifest/firefox.

"about:debugging" add temporary Add-on, locate -> bug report repo root folder manifest.json. Fire.
Browser instance works fine, WebWorker instance responds accordingly.

Environment

Playwright Version: 1.57.0
Operating System: Linux Mint 22.1, Cinnamon 64-bit
Node version: v20.19.6; only ES modules used
Browser: Chromium, FireFox
manifest.json Version: 3
System:
Linux: 6.8.0-58-generic
Memory: 32.00 GB

[pavelfeldman]

We don't repro / address use cases that are passing custom arguments to the browser directly (https://github.com/44xtc44/BUG-Playwright-fail-WebWorker-Extension/blob/main/tests/end2end/chromium.js#L29), so we won't be looking at this issue. If you find a solution that other users can benefit from, please comment on this closed issue and hopefully they can use your advice. Thanks!

[44xtc44]

@pavelfeldman Thank you for the quick answer :)

My Browser extension with webWorker runs smoth and tests with Playwright now.
If I do the following:

• worker module is not listed in "manifest.json" at all (fix "test" run at all - had no impact in prod)
• File extension of my JavaScript modules is ".mjs" (fix "test" run at all - had no impact in prod, fix workers unsupported import error)
• required URL style for path to worker module
  this.worker = new Worker(new URL("pathToWorker", import.meta.url), {type: "module",}))
• A boss module with class methods (async) to spawn/kill a worker
• worker module sends events (errors) as JSON (fix Uncaught DataCloneError)
• Playwright test module command line args for chromium

     ... 
      const browserContext = await chromium.launchPersistentContext(userDataDir, {
      channel: "chromium",
      headless: false,
     args: [
        `--disable-extensions-except=${pathToExtension}`, // no more error messages if out comment
        `--load-extension=${pathToExtension}`,
        `--allow-file-access-from-files`,  // my extension loads
      ],});
     ...

Playwright is not showing my animation. I guess there is a Chromium Command Line Switch

Best regards