presto-main/src/main/java/io/prestosql/execution/TaskSource.java/TaskSource/isNewer
class TaskSource:    private boolean isNewer(TaskSource source)
    {
        // the specified source is newer if it changes the no more
        // splits flag or if it contains new splits
        return (!noMoreSplits && source.isNoMoreSplits()) ||
                (!noMoreSplitsForLifespan.containsAll(source.getNoMoreSplitsForLifespan())) ||
                (!splits.containsAll(source.getSplits()));
    }