[Bug]: electron.launch() fails with Electron 30+ - "bad option: --remote-debugging-port"

[MihaiSora]

Version

1.58.0

Steps to reproduce

1. Clone the reproduction repo
2. npm install
3. npm test
4. Observe the error: bad option: --remote-debugging-port=0

Expected behavior

Electron app launches successfully and Playwright connects via CDP.

Actual behavior

Launch fails immediately with:

electron.launch: Process failed to launch!
Call log:
  - <launching> .../Electron.app/Contents/MacOS/Electron --inspect=0 --remote-debugging-port=0 main.js
  - [err] .../Electron.app/Contents/MacOS/Electron: bad option: --remote-debugging-port=0

The Electron binary rejects --remote-debugging-port=0 as an invalid CLI argument before any JavaScript executes.

Root cause: Playwright passes --remote-debugging-port=0 as a CLI argument, but Electron 30+ rejects this flag at the CLI level before the Node.js script starts.

Tested with both Playwright 1.57.0 and 1.58.0 - same issue.

Additional context

• Electron docs list --remote-debugging-port as supported, but it only works via app.commandLine.appendSwitch() in Electron 30+, not as a CLI argument
• This affects both the npm electron package and custom executablePath configurations
• The nodeCliInspect fuse documentation doesn't mention --remote-debugging-port being affected
• Workarounds attempted (all failed):
  • Pass flag after script path with -- → Flag ignored
  • Environment variable + app.commandLine.appendSwitch() in app → app.commandLine undefined due to ES module hoisting
  • Playwright's loader.js preload → Never executes because Electron rejects the flag first
• Cypress documented similar issues: cypress-io/cypress#7994

Environment

System:
  OS: macOS 15.6.1
  CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  Memory: 160.07 MB / 16.00 GB
Binaries:
  Node: 20.19.6 - /node/20.19.6/bin/node
  Yarn: 4.12.0 - /yarn/4.12.0/bin/yarn
  npm: 10.8.2 - /node/20.19.6/bin/npm
npmPackages:
  @playwright/test: 1.58.0
  electron: 36.9.5