We got lots of failures because scroll-snap-coordinate ans scroll-snap-destination should be discrete animation. [1] Gecko: http://searchfox.org/mozilla-central/rev/b52285fffc13f36eca6b47de735d4e4403b3859e/layout/style/nsCSSPropList.h#3660,3673 [2] Servo: http://searchfox.org/mozilla-central/rev/b52285fffc13f36eca6b47de735d4e4403b3859e/servo/components/style/properties/longhand/box.mako.rs#719,728

Now I don't think it's worth making them animatable even if they are discrete type, since they have been dropped from the latest spec (See bug 1218265 comment 1). We should just ignore those properties in test_transitions_per_property.html for stylo?

(In reply to Hiroyuki Ikezoe (:hiro) from comment #1) > Now I don't think it's worth making them animatable even if they are > discrete type, since they have been dropped from the latest spec (See bug > 1218265 comment 1). We should just ignore those properties in > test_transitions_per_property.html for stylo? Yes. I will skip all the failures in test_transitions_per_property.html for stylo in Bug 1292283. Use this bug to track this problem.

To make sure I understand - is the proposal here to ship a behavior change dropping support for animating these properties, since we plan to drop support for the properties themselves anyway? Do we consider this to be risky?

(In reply to Bobby Holley (:bholley) (busy with Stylo) from comment #3) > To make sure I understand - is the proposal here to ship a behavior change > dropping support for animating these properties, since we plan to drop > support for the properties themselves anyway? Yes, but not now. (Wait for Gecko's change.) Do we consider this to be risky? After removing these properties from Gecko. This wouldn't be risky. I believe we will drop these properties in another bug for Gecko. After doing that, we can do the same thing for Servo in this (especially for animations) or other bugs. For now, I am not planning do anything because we have to wait Gecko's change. Currently, we skip the tests of these two properties for Servo in test_transitions_per_property.html, so this bug wouldn't affect Bug 1320841.

Though I think the behavior change (these properties are discrete animation on gecko but normal animation on stylo) is pretty low risk since I guess there are not so many sites that uses those properties and even less animation. That's said, I don't think we should take much time for this issue. So, just make those properties as discrete on stylo too!

Comment on attachment 8896835 [details] Bug 1387941 - Make scroll-snap-{coordinate, destination} discrete animation. https://reviewboard.mozilla.org/r/168132/#review173286

Pushed by hikezoe@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/0c374dbcd5c6 Make scroll-snap-{coordinate, destination} discrete animation. r=daisuke