What is the right way of notifying media session about non-fatal errors in Media3?

[bstokrocki]

Our media application is available on both Android mobile (with support of Android Auto) and on Android Automotive. We already migrated to Media3, so we're using MediaLibraryService, however there's this one case we're not sure how to cover in Media3.
We have some custom actions that are not always available, like adding content to favorites, which requires user to be logged in. We're providing an alternative variant of action's icon to indicate that it's not available at the moment, but user can of course still click on it. What we previously did in this case is setting a non-fatal error in the media session like this:

mediaSession.setPlaybackState(
     // We would take the current playback state rather than setting STATE_ERROR
     // as the error we surface is non-fatal, playback can continue normally, we're only
     // interested in providing an error message 
     PlaybackStateCompat.Builder(controller.playbackState)
         .setErrorMessage(errorCode, errorMessage)
         .build()
 )

This was especially important on Android Automotive as this allowed us to surface meaningful error message to the user in form of a toast. However, due to automatic state handling in Media3, this no longer seems to be possible. I noticed that this issue is being mentioned in the docs: https://developer.android.com/guide/topics/media/session/mediasession#automatic-state.
I was wondering if there's already any solution that I could go for to cover this case in Media3?

[marcbaechinger]

Thanks for your report.

That's a known issue and there is currently no good way to do this with Media3 I'm afraid.
We agree it's useful to have this for the use cases you explained.

We already have #543 so I mark this as a duplicate. We hope to have this ready for the next release.

A question around your actual implementation with the legacy library: once you have sent the error code and message as above, how long do you keep that error in the PlaybackStateCompat? Are you simply clearing this message with the next update of the playback state or do you keep it until a certain event in your app happens?

[bstokrocki]

Hi, thank you for the answer and sorry for the duplicate!

Glad to hear that solution might be soon available.

To answer your question - the error was cleared by the next update of the playback state.

[marcbaechinger]

Many thanks! Very useful!

I'm closing in favor of the other issue.