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by spatulon 2296 days ago
I'd love to hear if they made any progress in tracking down the 'interesting WebRender bug' from https://news.ycombinator.com/item?id=22359574
2 comments

They have, it's suspected to be caused by a race condition with memory pressure events [0][1]. It looks like the patch is not included in Firefox 74 though.

[0] https://mozillagfx.wordpress.com/2020/03/02/moz-gfx-newslett...

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1617083

yeah our potential fix is on Firefox Beta right now, if people want to try it out!
I think it's tracked under https://bugzilla.mozilla.org/show_bug.cgi?id=1604492 It's still open, but it seems people haven't been able to hit the bug on the last few nightlies (this is also my experience), so it's possible the bug was quietly fixed as a side effect of some other patch.
Programming can be so easy: "Oh hey, it fixed itself!"

Programming can be so hard: "So then what was the bug?"

You can bisect to try and figure out where exactly the bug "fixed" itself. Not easy with a bug that can't be triggered reliably, of course.
Something something Schrodinger's Bug...
And the awful thing if you can’t pinpoint what caused and fixed it is that it can more easily regress later.