Trace.presents holds (ts, args.present) pairs and was sorted as whole tuples.
Two present events with the same timestamp, one with a present number and one
without, made the sort compare None with an int and raised an uncaught
TypeError, so trace_digest exited with a traceback instead of a digest. The
sort now keys on the timestamp; it is stable, so tied events keep the order of
the trace.
MarcZX10
d27e90bb8a