mutation event handler error: error.JSExecCallback (16x) and hangs

[marcuskbr]

On Ubuntu 22.04.5 lightpanda issues 16 times the same error and then hangs (not using CPU time).

./lightpanda-2025-03-14 version
43f42f9
./lightpanda-2025-03-14 fetch --dump https://WWW.minefun.io/
info(browser): GET https://WWW.minefun.io/ 200
info(browser): fetch https://WWW.minefun.io/assets/index-3423aac2.js: http.Status.ok
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
error(events): mutation event handler error: error.JSExecCallback
info(events): mutation observer event handler error: TypeError: r is not iterable
^C

[krichprollsch]

I have a similar, but not exactly the same error:

info(events): mutation observer event handler error: TypeError: o is not iterable
error(events): mutation event handler error: error.JSExecCallback

I think it could come from this code:

    new MutationObserver(o => {
        for (const r of o)
            if (r.type === "childList")
                for (const l of r.addedNodes)
                    l.tagName === "LINK" && l.rel === "modulepreload" && s(l)
    }