Can't recover from JS loops

[AgentOrange]

On Pale Moon 28.16.0 (official 64-bit build) on Fedora 32, I accidentally clicked "Debug script" instead of "Stop Script" on this page, and bricked the browser when trying to close the debugger (it consumed 100% of 1 core for over 40 minutes as I did other tasks, stuck as pictured in the attached screenshot.)

Since this browser plans to keep the UI thread married to the JS thread indefinitely, could there at least be more frequent hang-check interrupts?

[AgentOrange]

(Granted, this is less of an issue now that UBO supports blocking JS per-domain, but it still seems like a bug per se…)

[Moonchild]

Since this browser plans to keep the UI thread married to the JS thread indefinitely

Not sure where you are getting this information but that's not how things work internally. You probably mean that we won't be spawning separate program processes for web content (that can hang up just as hard, by the way) that you -might- be able to kill from a UI process, if you're lucky.

could there at least be more frequent hang-check interrupts?

Some types of hangs are very hard to catch with a check, e.g. recursion issues. The main problem though is that you didn't stop the script but rather tried to feed whatever misbehaving script caused this into the JS debugger of devtools, which is in itself JS-driven, too. Depending on the type of hang, it may just go over the edge and never recover, as you've noticed, if the script that's hanging is not in a sane execution state.