> Seems like you could just copy your current code into ImmutableSortField sure, but ImmutableSortField would have the discovery problem - who would know to use it - and wouldn't actually prevent any of the fatals.
I will revert SortField and the other changes (tomorrow), and I'll remove the ticket from the list for this release, so that gives us time to find a solution with backwards compatibility, if at all (we could even just say it's a known risk).