Kartikaya Gupta (email:kats@mozilla.staktrace.com) Reporter
	Description • 8 years ago

After bug 1180799 landed I'm seeing a lot of unexpected spontaneous flings happening after pinch actions in Fennec Nightly. I put a video up at https://people-mozilla.org/~kgupta/bug/1180799.mp4 - it's pretty easy to reproduce. I haven't tried this on a desktop (non-zoomable) platform.

Ideally we can fix this soon, because it's a pretty bad regression that makes the browser hard to use. If we don't have a path to fixing it soon we should disable this behaviour, at least on zoomable platforms.

	Botond Ballo [:botond]
	Comment 1 • 8 years ago

Unfortunately I'm on PTO until Monday, and probably won't have a chance to investigate this until then.

If we want to quickly disable this behaviour without a full backout of the bug 1180799, #ifdefing out the call to HandleEndOfPan() in OnScaleEnd() [1] on Android (or all platforms if necessary) should do it.

[1] http://searchfox.org/mozilla-central/rev/944f87c575e8a0bcefc1ed8efff10b34cf7a5169/gfx/layers/apz/src/AsyncPanZoomController.cpp#1495

	Kartikaya Gupta (email:kats@mozilla.staktrace.com) Reporter
	Comment 2 • 8 years ago

(In reply to Botond Ballo [:botond] from comment #1)
> If we want to quickly disable this behaviour without a full backout of the
> bug 1180799, #ifdefing out the call to HandleEndOfPan() in OnScaleEnd() [1]
> on Android (or all platforms if necessary) should do it.

I tried ifdefing this out but it didn't do the trick. It must be code changes elsewhere that are the problem. In retrospect, not surprising, because the HandleEndOfPan is only called if zooming is not allowed, so it's probably not getting hit on Fennec.

I'm going to back out the patch for now.

	Pulsebot
	Comment 3 • 8 years ago

Pushed by kgupta@mozilla.com:
https://hg.mozilla.org/integration/mozilla-inbound/rev/5e1026baaf23
Back out cset 456dbb5c2b93 (bug 1180799) for causing unexpected behaviour. r=backout

	Botond Ballo [:botond]
	Comment 4 • 8 years ago

(In reply to Kartikaya Gupta (email:kats@mozilla.com) from comment #2)
> I tried ifdefing this out but it didn't do the trick. It must be code
> changes elsewhere that are the problem. In retrospect, not surprising,
> because the HandleEndOfPan is only called if zooming is not allowed, so it's
> probably not getting hit on Fennec.

Thanks for testing. Based on this result, I've developed a theory as to what's going wrong, described in bug 1180799 comment 38.

	Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)
	Comment 5 • 8 years ago
backout bugherder

https://hg.mozilla.org/mozilla-central/rev/5e1026baaf23