1158616 - Attach metadata to synchronous reflow markers about which property get/set or method call triggered the synchronous reflow

Status: RESOLVED INVALID

(DevTools :: Performance Tools (Profiler/Timeline), defect, P3)

Description

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

I'm debugging a performance issue that boils down to a synchronous reflow caused by jQuery.event.fix. I can see which line the synchronous reflow was triggered on, but unfortunately, that doesn't give me as much as I'd hoped:

> i = copy.length;
> while ( i-- ) {
>   prop = copy[ i ];
>   event[ prop ] = originalEvent[ prop ]; // <---- this line
> }

It would be really nice if we just had something like

  Cause: Node.prototype.[get clientHeight]

As it is now, the tool gives me no idea whether it is a getter on originalEvent or a setter on event, nor which property.

Comment 1

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

FWIW, copy is this set of properties:

altKey, bubbles, cancelable, ctrlKey, currentTarget, eventPhase, metaKey, relatedTarget, shiftKey, target, timeStamp, view, which, button, buttons, clientX, clientY, offsetX, offsetY, pageX, pageY, screenX, screenY, toElement

Comment 2

[Victor Porof [:vporof][:vp]]

Triaging. Filter on ADRENOCORTICOTROPIC (yes).

Comment 3

[Jan Honza Odvarko [:Honza] (always need-info? me)]

This report is related to the old DevTools Profiler.
The Performance panel now points to the new Firefox profiler available at profiler.firefox.com
Closing as Invalid bug