[Development] [fix]: Assistant (and others) burning CPU because of #f27d1ccbb24ec2fd4098f2976503478831006cc8 ?

[René J.V. Bertin]

On Tuesday August 29 2017 02:02:59 Gabriel de Dietrich wrote:
>FYI: QCocoaMenu: Stop update timer (Merged)<https://codereview.qt-project.org/203791>

Thanks for the heads-up.

>
>On Aug 29, 2017, at 9:00 AM, Thiago Macieira <thiago.macieira at intel.com<mailto:thiago.macieira at intel.com>> wrote:
>
>On Monday, 28 August 2017 17:06:18 PDT René J.V. Bertin wrote:
>       killTimer(m_updateTimer);

>Yeah, if you don't kill the timer, it will keep firing.

Which we just rediscovered :) Funny though, apparently 1 misdirected startTimer() call can turn any application in a CPU hog that burns cycles without ever doing anything. Wouldn't it be safer for QObject::timerEvent() to kill any timer that triggers it, possibly even do an abort if it can do some kind of runtime debug mode detection? At least then it's set to a 0 (zero) interval?

It took me an unreasonable amount of time trying to figure out the reason for the burning, the fact that QCocoaMenu::timerEvent() could be being called as fast as possible and for nothing occurred to me only after trying all other possibilities. And I knew only the timer change could be the culprit; I can only imagine how much more time I'd have spent if this bug had been latent for a few months.

BTW, the 1st application in which I noticed this doesn't use the native menubar at all. I'm going to have to try and understand what business it has using QCocoaMenu...

R.