Fix media_player alexa power control bug

[pvizeli]

Description:

With new strict media control handling on 0.92 not all media player support now the power control.

[andrewsayre]

I assume this code is called during setup of the Alexa integration?

The thing to keep in mind is that supported_features in media_player are not static today--they change throughout the entity lifetime. Some platforms even return 0 when the entity isn't available and others will always return a base set of features and then change certain flags based on state.

I think we're not going to get a reliable set of capabilities for Alexa if this code runs this way... but not sure there's a way around it until we fix this issue with the media player platform....

[emontnemery]

not sure there's a way around it until we fix this issue with the media player platform

Does that imply the supported_features should not be allowed to change?

[pvizeli]

Yes. This code is called on the discovery of devices from alexa itself.

[balloob]

@emontnemery correct. Supported features is supposed to be static. For Media Player we need to introduce a new flag attribute of the currently supported features (repeat, prev, next etc).

[emontnemery]

@balloob OK, so the integration (say cast) should statically support some features, but it's still possible to flag the currently supported features depending on what media is playing. That makes sense, thanks!