RunTime exception on destroyed player

[tbrixi]

Have you read the FAQ and checked for duplicate open issues?: yes

What version of Shaka Player are you using?: 2.3.7

Can you reproduce the issue with our latest release version?: yes

Can you reproduce the issue with the latest code from master?: yes

Are you using the demo app or your own custom app?: custom

If custom app, can you reproduce the issue using our demo app?: no

What browser and OS are you using?: Chrome Version 66.0.3359.117 (Official Build) (64-bit)

What are the manifest and license server URIs?:
(NOTE: you can send the URIs to shaka-player-issues@google.com instead, but please use GitHub and the template for the rest)
(NOTE: a copy of the manifest text or an attached manifest will not be enough to reproduce your issue, and we will ask you to send a URI instead)

What did you do?
step to reproduce:

1. start video playback
2. block video source url (simulate server not responding)
3. on error unload and destroy player
   shaka.Player.unload();
   shaka.Player.destroy();
4. async handleStreamingError is fired when player is already destroyed

What did you expect to happen?
ignore error events when player is destroyed

What actually happened?
RunTime exception TypeError: Cannot read property 'onError' of null;

streaming_engine.js (line 2200):
shaka.media.StreamingEngine.prototype.handleStreamingError_ = function(error) {

this.playerInterface_.onError(error);
where playerInterface_ is null;

this.config_.failureCallback(error);
where config_ is null
}

[theodab]

It's hard to say what the exact problem is without being able to see your custom app.

One possibility is that... I do notice that, in your repro steps, you say that you called:

shaka.Player.unload();
shaka.Player.destroy();

Is that the exact code? Player.unload and Player.destroy are both asynchronous methods. I'm not sure what kind of behavior there will be if you destroy without waiting to first unload. I tested a little bit, and calling unload and then destroy immediately afterwards does seem to have a chance of causing weird problems.

Could you try something like:

await shaka.Player.unload();
await shaka.Player.destroy();

or, if you don't want to use ES6 syntax:

shaka.Player.unload().then(function() {
  return shaka.Player.destroy();
}).then(function() {
  // Post-shutdown code here
});

[joeyparrish]

Although they are both async methods, unload() followed by destroy() without waiting should not cause errors. I'm putting this back in queue to be reproduced by this week's bug cop.

[michellezhuogg]

I tried to reproduce the issue with network throttling, but could not see the exception.
Could you please provide more detailed instructions to reproduce the issue, or some sample code? You may send it to shaka-player-issues@google.com if you prefer to keep it private.

[tbrixi]

Problem is partly in our implementation when we setting player to null immediately after destroy().
I am able to reproduce problem on "shaka-player\docs\tutorials\basic-usage.md", if I set player to null after destroy();

var player;
...
function onError(error) {
// Log the error.
console.error('Error code', error.code, 'object', error);
player.unload();
player.destroy();
player = null;
}

shaka.js:284 Uncaught (in promise) TypeError: Cannot read property 'onError' of null
at cg. (shaka.js:284)

[TheModMaker]

This was fixed as part of #1323, but that wasn't added to a v2.3.x release. I've pulled the relevant parts of that commit into a cherry-pick onto the v2.3.x branch and it will appear in the v2.3.8 release. This has already been fixed on master.