Bug 277588 – iOS Web Extension service worker fails to load unless I delay all JS via setTimeout

• Status: RESOLVED
• Resolution: DUPLICATE
• Component: Service Workers

[@fregante]

In the latest version of Refined GitHub on the App Store, currently v24.7.10, the service worker fails to load: https://apps.apple.com/us/app/refined-github/id1519867270

- This only happens on iOS, including the simulator
- There are no syntax errors or uncaught errors in the code
- The same file works when loaded via `background.scripts` instead of `background.service_worker`
- It's impossible to debug because the "Service worker" does not appear in Safari's Develop -> MyDevice list
- It seems to occasionally run on my iPhone, e.g. it responds to action.onClicked, but rarely, and it never responds to runtime.sendMessage.

Most importantly:

- The same file works if I wrap the entire background.js contents in `setTimeout(() => {/*contents*/}, 1000)`

Versions:

- iOS 17.5 and 17.6 iPhone 15 Pro Max Simulator

Questions:

- If you'd like me to attach a repro, would .xcarchive be enough?
- How can I debug service worker failures on iOS? It seems impossible because "Automatically Show Web Inspector for JSContexts" does not work for other devices

Repro:

- GitHub repo with the extension: https://github.com/refined-github/refined-github/tree/24.7.10
- It needs Node 21+, `npm install && npm run build`. The Xcode project is in /safari

References:

- https://github.com/refined-github/refined-github/issues/7590
- https://github.com/refined-github/refined-github/issues/7629

Workarounds:

- I'll have to ship `background.scripts` until this is resolved

[Radar WebKit Bug Importer]

<rdar://problem/133593437>

[@fregante]

Some updates:

- It has been working recently, maybe thanks to iOS 17.6.1. I have not checked the Simulator though
- Version 24.8.20 has been released on the App Store and it was reverted to a background script anyway

If you need a build of the service worker version let me know. 

Overall I wish there was *any* way to debug these issues. I don't know if the service worker can be debugged at all in extensions, if it fails on launch.

[Brent Fulgham]

This was actually resolved in:
<rdar://126825362>

[Brent Fulgham]

*** This bug has been marked as a duplicate of bug 274331 ***