Blocking Prisma. We currently support using user defined tables as composite types, but we cannot see them in pg_type. Ditto for dolt system tables, even with dolt_show_system_tables active.
Similarly we don't have any values set for the reltype column in pg_class, which would correspond with the associated row in pg_type.
I can look into this more tomorrow.
TODO comments here or here seem to be the places that would need to change.