If the player is started with --idle and the osc-tracklist script-message
is called then the tracks_osc table will be nil,
which caused the OSC to crash due to attempting to index a nil value.
This appears to be because the osc_tracklist variable is both
initialised and updated by (ultimately) the render() function, which
is not run when the player is idling.
Rather than mess with the existing OSC logic it's easier to either
add this single check, or alternatively to initialise the the tracks_osc
table somewhere before this.
The code assumed that the value of the profile-restore field is
"default" for such profiles, but the C implementation is such
that the field is intentionally omitted in such case.
This resulted in incorrectly trying to restore such profiles. However,
there are no stored values with profile-restore=default, so it only
resulted in a harmless warning, but otherwise behaved correctly (i.e.
nothing is restored).
Fix the condition by taking into account that missing field means
"default", so that it doesn't try to restore in such case, and
avoid the warning.