1194201 - Animations that are removed while the animation-inspector is open cause exceptions and the UI isn't updated

Status: RESOLVED WORKSFORME

(DevTools :: Inspector: Animations, defect)

Description

[Patrick Brosset <:pbro>]

This is a recent regression. FF41 doesn't have the problem.
I saw this occur on Nightly (fresh fx-team build, FF43).

STR:
- Open the inspector on this page: http://tympanus.net/Development/DialogEffects/ricky.html
- Switch to the animation inspector sidebar.
- Click on the "Open Dialog" button in the page.
=> Animations appear in the inspector sidebar.
- Click to close the dialog.
=> Removed animations don't disappear as they're supposed to, and following backend exception is logged:

console.error: 
  Error sending event: mutations
console.error: 
  Message: TypeError: v is undefined
  Stack:
    types.addActorType/type<.write@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:298:7
types.addDictType/<.write@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:233:23
types.addArrayType/<.write/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:199:40
types.addArrayType/<.write@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:199:24
Arg<.write@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:450:12
Request<.write/str<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:619:1
Request<.write@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:617:15
Actor<._sendEvent@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:882:16
Actor<.initialize/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:866:11
emitOnObject@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:112:9
emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:89:38
exports.AnimationsActor<.onAnimationMutation@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/animation.js:680:7
MutationCallback*exports.AnimationsActor<.getAnimationPlayersForNode<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/animation.js:607:21
actorProto/</handler@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/protocol.js:1013:19
DSC_onPacket@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/main.js:1586:15
ChildDebuggerTransport.prototype.receiveMessage@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/transport/transport.js:742:5

This comes from when the AnimationsActor tries to send the mutations event to the front-end.
For some reason we can't find a AnimationPlayerActor for one of the animations involved in the list of mutations, so <null> is sent instead, which the protocol doesn't like.

Relevant code is in AnimationsActor.onAnimationMutation (/toolkit/devtools/server/actors/animation.js) when the following code runs:

        let index = this.actors.findIndex(a => a.player === player);
        eventData.push({
          type: "removed",
          player: this.actors[index]
        });

For some reason, index is -1 here.
This didn't occur in the past.

Comment 1

[Nicolas Chevobbe [:nchevobbe][PTO - back on October 21]]

I would like to work on this bug. Can someone assign it to me please ? Thank you

Comment 2

[Patrick Brosset <:pbro>]

Sure. Were you able to reproduce this issue again. A lot of things have changed since I filed it.

Comment 3

[Nicolas Chevobbe [:nchevobbe][PTO - back on October 21]]

No, can't reproduce indeed.
Sorry, I should have looked before asking to assign.

Thanks

Comment 4

[Patrick Brosset <:pbro>]

No problem! You might be interested in bug 1247243 instead.