[paper-input] preventing exception when typing with mobile keyboard

[Juraci]

I got the following exception on paper-input when typing with the Android keyboard:

paper-input error
Cannot read property 'val' of undefined.

Steps to reproduce:

requirements:
Android smartphone with google chrome

1. Open Chrome dev tools and setup it for remote debugging
2. On the phone open this page dialog example
3. In the prompt dialog example type some text with the phone keyboard (has to be with the phone keyboard)
4. Click on confirm action on the dialogue

Expected: Dialog closes
Actual: Dialog remains opened with the error linked above

The fix in the pull request prevents this exception while maintaining the current behavior.

[waldemarnt]

👍

[miguelcobain]

@Juraci I wonder why this fix is needed. I'm generally opposed to merging fixes without knowing what is the root cause of it. Do you have any idea?

[Juraci]

@miguelcobain I did not have the time to dig deeper into why this is happening on the mobile only. I do suspect that the setValue method is being called after a dialog action has been made, but I do not know why this happens when using the mobile keyboard only.

A fix is definitely needed because the prompt dialog is currently unusable in mobile platforms

[miguelcobain]

@Juraci I think I know the root cause of the problem.
We're using run.next with setValue here: https://github.com/miguelcobain/ember-paper/blob/master/addon/components/paper-input.js#L144-L146

What I suspect is happening is that, by the time setValue runs, the template is already destroyed (especially on android due to low performance, I assume).
The proper fix would be to test if the component is destroyed, before calling setValue. We can test that checking this.isDestroyed value.

The code would become something like:

run.next(() => {
  if (this.isDestroyed) { return; }
  this.setValue(this.get('value'));
});

Could you please test this, and if it solves the issue, update the PR?

[Juraci]

@miguelcobain, sure I will do that.

[Juraci]

@miguelcobain you are correct, this solves the problem, just tested it here.

[miguelcobain]

@Juraci Great. While you're at it, could you please add an entry to the changelog?

[miguelcobain]

Thanks a lot for this!