[rules-users] NPE in SlidingTimeWindow$SlidingTimeWindowComparator

[Rob Crawford]

I'm getting a null pointer exception on either line 232 or 233 of SlidingTimeWindow. The only window I'm using is:

rule "Mark up to date"
       timer(int: 5m)
when
       $store: Store()
       exists (SensorReading (this.store == $store) over window:time(5m))
then
       ...
end

The rule never fires; this happens when the sliding time window is expiring tuples.

It appears the comparator needs to handle nulls, but there's nothing in the JavaDocs about that.