1062226 - CSS Animations - Interrupted by CSS Hover Events when transitions are also present

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[Thomas Brierley]

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/37.0.2062.94 Chrome/37.0.2062.94 Safari/537.36

Steps to reproduce:

1. Create a div with a basic animation and a transition with a non-zero duration.

2. Add a css hover event (does not need to contain any properties).

jsbin example:

http://jsbin.com/zowidavasote/1/edit


Actual results:

When hovering over the element: The style temporarily transitions to the initial state interrupting the animation.


Expected results:

The animation should play and not be interrupted by hovering when there are no styles declared on that event that affect it.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Fun interactions between animations and transitions....

Comment 2

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Not interesting to analyze until after bug 960465 is done.

Comment 3

[Thomas Brierley]

(In reply to Boris Zbarsky [:bz] from comment #1)
> Fun interactions between animations and transitions....

This might seem obscure, but regardless of how transitions are handled during an animation the CSS hover event causes an interruption regardless of what CSS properties or element it ultimately targets.

The actual scenario I found this issue in: An element with an animation and transition which do NOT occur simultaneously and a hover event used to target a child element. I think this is a valid use of these properties and an incorrect behaviour.

Comment 4

[Boris Zbarsky [:bzbarsky]]

Thomas, I wasn't saying this isn't a bug; it clearly is.  Just saying that it depends on a complex part of the code... and per dbaron's comment that code is currently being rewritten, which may well fix the bug.  If not, we would want to debug after the rewrite anyway.

Comment 5

[Thomas Brierley]

(In reply to Boris Zbarsky [:bz] from comment #4)
> Thomas, I wasn't saying this isn't a bug; it clearly is.  Just saying that
> it depends on a complex part of the code... and per dbaron's comment that
> code is currently being rewritten, which may well fix the bug.  If not, we
> would want to debug after the rewrite anyway.

OK, i just didn't want it to be misinterpreted as entirely redundant - and i can empathise with any disdain towards interaction of animations and transitions :P I hope no one looses their sanity in the re-write.

Cheers

Comment 6

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Fixed by bug 960465 (or, very unlikely, something else that landed the same day).