[WEB COMPAT] Sveltekit tutorial's web container immediately crashes #326

mjoanmiller commented 2026年06月25日 10:54:11 +02:00

Confirmation Checklist

• I confirm that this issue occurs on the latest release of Phoenix. You can check what the latest version is on the Releases page.
• I confirm that this issue is NOT already listed on the Website Compatibility wiki page.
• I confirm that this issue has NOT already been reported on the Codeberg issue tracker, the GitLab issue tracker, and/or the GitHub issue tracker.

Which domain(s) are you experiencing this issue on?

https://svelte.dev

What web browser(s) are you using with Phoenix?

Firefox

Other

No response

What operating system(s) are you experiencing this issue on?

Arch Linux

Other

No response

What version of Firefox/Gecko and Phoenix are you using?

152.0.2 (Phoenix: 2026年06月10日.1)

If you remember, what version of Firefox/Gecko and Phoenix did you first notice the issue on?

No response

Does the issue occur on a new browser profile?

• Yes
• No

Please share your browser's distribution ID.

mozilla-official

Please share your browser's update channel.

No response

Please share a list of your currently installed browser add-ons/extensions, as well as the versions you have installed.

No response

Please explain the issue you are experiencing.

The web container in the sveltekit tutorial breaks with the error message included in the screenshot.

Please provide detailed steps to reproduce the issue.

https://svelte.dev/tutorial/kit/introducing-sveltekit visit and wait for the web container to crash

### Confirmation Checklist - [x] I confirm that this issue occurs on the **latest release** of Phoenix. You can check what the latest version is on [the `Releases` page](https://codeberg.org/celenity/Phoenix/releases). - [x] I confirm that this issue is **NOT** already listed on [the Website Compatibility wiki page](https://phoenix.celenity.dev/compat). - [x] I confirm that this issue has **NOT** already been reported on [the Codeberg issue tracker](https://codeberg.org/celenity/Phoenix/issues), [the GitLab issue tracker](https://gitlab.com/celenityy/Phoenix/-/issues), **and/or** [the GitHub issue tracker](https://github.com/celenityy/Phoenix/issues). ### Which domain(s) are you experiencing this issue on? https://svelte.dev ### What web browser(s) are you using with Phoenix? Firefox ### Other _No response_ ### What operating system(s) are you experiencing this issue on? Arch Linux ### Other _No response_ ### What version of Firefox/Gecko and Phoenix are you using? 152.0.2 (Phoenix: 2026年06月10日.1) ### If you remember, what version of Firefox/Gecko and Phoenix did you first notice the issue on? _No response_ ### Does the issue occur on a new browser profile? - [x] Yes - [ ] No ### Please share your browser's distribution ID. mozilla-official ### Please share your browser's update channel. _No response_ ### Please share a list of your currently installed browser add-ons/extensions, as well as the versions you have installed. _No response_ ### Please explain the issue you are experiencing. The web container in the sveltekit tutorial breaks with the error message included in the screenshot. ### Please provide detailed steps to reproduce the issue. https://svelte.dev/tutorial/kit/introducing-sveltekit visit and wait for the web container to crash

koru commented 2026年06月25日 20:35:36 +02:00

I can reproduce.

Log as text:

Yikes!
We couldn't start the app. Please ensure [third party cookies](https://support.mozilla.org/en-US/kb/third-party-cookies-firefox-tracking-protection) are enabled for this site, and disable Enhanced Tracking Protection.
If you have 'Delete cookies and site data when Firefox is closed' enabled in `about:preferences#privacy`, make sure `svelte.dev` is included as an exception.
**The WebAssembly.Memory object cannot be serialized. The Cross-Origin-Opener-Policy and Cross-Origin-Embedder-Policy HTTP headers can be used to enable this.**

I can reproduce. Log as text: ```markdown Yikes! We couldn't start the app. Please ensure [third party cookies](https://support.mozilla.org/en-US/kb/third-party-cookies-firefox-tracking-protection) are enabled for this site, and disable Enhanced Tracking Protection. If you have 'Delete cookies and site data when Firefox is closed' enabled in `about:preferences#privacy`, make sure `svelte.dev` is included as an exception. **The WebAssembly.Memory object cannot be serialized. The Cross-Origin-Opener-Policy and Cross-Origin-Embedder-Policy HTTP headers can be used to enable this.** ```