In bug 1004377, I made CSS animations start dispatching events when the corresponding @keyframes rule is empty. This basically consisted of removing some occasions where we skipped event dispatch when the array of keyframes was empty. However, when we encounter an animation-name that doesn't match any @keyframes rule we would still generate an ElementAnimation with an empty set of keyframes. Prior to bug 1004377 we would not dispatch events in this case but now we do. The spec is pretty clear that we shouldn't: Any animation for which both a valid keyframe rule and a non-zero duration are defined will run and generate events; this includes animations with empty keyframe rules. http://dev.w3.org/csswg/css-animations/#events The non-zero duration condition is wrong but the rest makes sense. I've tested Chrome and IE and they don't dispatch events in this case but they also don't dispatch events for an empty keyframe rule which the spec clearly requires. Bug 1031319 fixes this behavior for when animation-name is none or empty but not for non-matching names.

When animation-name does not match a keyframes rule, we should not dispatch animation events as per: "Any animation for which both a valid keyframe rule and a non-zero duration are defined will run and generate events; this includes animations with empty keyframe rules." http://dev.w3.org/csswg/css-animations/#events Since bug 1004377, however, we started dispatching events in this case because we no longer ignore animations whose set of keyframes is empty. This patch checks for a matching keyframes rule in BuildAnimations and if one is not found, no corresponding animation is generated.

Depending on which lands first, this or bug 1032573, this patch might have to be landed separately

On further thought, I'm not entirely sure what the correct behavior should be if the referred-to @keyframes rule is added later. Should the animation start then or not? The spec doesn't seem to answer this. Might be a question for www-style.

(In reply to Brian Birtles (:birtles) from comment #3) > On further thought, I'm not entirely sure what the correct behavior should > be if the referred-to @keyframes rule is added later. Should the animation > start then or not? The spec doesn't seem to answer this. Might be a question > for www-style. http://lists.w3.org/Archives/Public/www-style/2014Jul/0044.html Note that attachment 8449911 [details] [diff] [review] from this bug makes us do (b) in that mail, the same as Chrome.

Comment on attachment 8449911 [details] [diff] [review] part 1 - Don't generate animations when the animation-name doesn't match r=dbaron

Try (part 1 only): https://tbpl.mozilla.org/?tree=Try&rev=0d4fdf6243f4

Comment on attachment 8452125 [details] [diff] [review] part 2 - Add tests to test_element-get-animation-players.html which checks for animation-name: missing It would probably be good to remove the @keyframes notyet rule from the stylesheet when you're done with it. r=dbaron

(In reply to David Baron [:dbaron] (UTC-7) (needinfo? for questions) from comment #10) > It would probably be good to remove the @keyframes notyet rule from the > stylesheet when you're done with it. Fixed. https://hg.mozilla.org/integration/mozilla-inbound/rev/40a3b13a460b