Topic/Reply Textbox Lagging using Phoenix Patchset on Firefox

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AI-generated summary

A user reports a lagging issue with the topic/reply textbox when using the Phoenix patchset on Firefox, linking to a bug report. Another user responds with a fix suggestion: enabling javascript.options.baselinejit resolves the issue but at a security cost. The response notes poor optimization, with console errors and performance degradation likely affecting other browsers that disable JIT, such as Cromite, Edge, Safari, Tor Browser, and Vanadium. The user also mentions that the issue appears to be related to the Composer component and that disabling JIT causes the lag, though they haven’t seen any console spam. The user concludes by asking if others are experiencing the same issue.

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Hi all, x-posting this bug from the one I filed with Phoenix (Firefox hardening patchset, also used by IronFox on Android):

It seems the issue is relating to the Javascript used by this feature, not sure if this is something that can be resolved or not but figured it was worth flagging. This behavior doesn’t exhibit itself in Chromium browsers, or hardened forks like Vandium

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Reply on the bug tracker is:

Thanks for the report! I apologize for the delayed response here. I was able to replicate the issue, and it appears that, at the cost of security, setting javascript.options.baselinejit to true should resolve it. This functionality appears to be very poorly optimized - I can see it spamming console errors even on stock Firefox. The degraded performance likely occurs on other browsers that disable JIT as well (ex. Cromite, Microsoft Edge, Safari, Tor Browser, Vanadium), so it’s definitely something they need to fix.
I went ahead and documented this on the Web Compat page.

I did not see any spamming in the console, can you share that with us?

I did have a little look at profiling, clearly we can not reproduce any of this on browsers that JIT compile, but from what I can tell the slowdown is not coming from ProseMirror the underlying library.

@cmahns can you confirm that you notice no slowdown on default setup when you type stuff into https://prosemirror.net/

From what I can tell @david / @renato the slowest parts when typing are coming from queuing stuff on the Ember runloop.