Comment 6 for bug 1266478

This is required for the implementation of playlists within the music-app.

The following structure is currently used:

{
    "playlist": {
        "name": "test",
        "tracks": [
            {"file": "abc", "title": "A"},
            {"file": "def", "title": "D"}
        ]
    }
}

However using an index with an expression of ["playlist.name", "playlist.tracks.file", "playlist.tracks.title"] or ["playlist.name", "playlist.tracks"] doesn't work as expected, as stated in the bug description.