Firefox-based browsers hanging completely for 6-8 seconds straight when loading Misskey

[temtemy]

💡 Summary

This bug first appeared in 2024.5.0. Can be seen even when logged out (haven't tested while logged in to one that has upgraded to 2024.5.0 or 2024.7.0 yet). The hanging (which also affects the UI of the browser, which is strange because e10s/multiprocess should've prevented this and only made it so that the Misskey tab is the only one hanging) can last up to 8 seconds straight before the browser can register any action from me again.

The hanging will only happen the first time you load the Misskey in a browser session. However since I close the browser often when I'm done with it, all this hanging can annoyingly add up over time.

Example URLs:

• https://misskey.io/tags/Misskey (2024.5.0 as of writing)
• https://mk.udongein.reisen/tags/Misskey (2024.7.0)

🥰 Expected Behavior

Loading any webpage of a Misskey 2024.5.0+ instance shouldn't hang at all in a new-enough PC that is using Firefox

🤬 Actual Behavior

Loading any webpage of a Misskey 2024.5.0+ instance (I usually do the /tags section since I like to look at other instances' hashtag timelines for the most up-to-date info) hangs Firefox, even with a beefy PC like mine as you can see below.

📝 Steps to Reproduce

No response

💻 Frontend Environment

* Model and OS of the device(s): ASUS laptop with Ryzen 7 4800H, Windows 11 23H2 x64
* Browser: Firefox 128.0.3
* Server URL: mk.udongein.reisen
* Misskey: 2024.7.0

🛰 Backend Environment (for server admin)

No response

Do you want to address this bug yourself?

• [ ] Yes, I will patch the bug myself and send a pull request