[jboss-jira] [JBoss JIRA] (JBRULES-3466) sum with no matching values results in NPE on reverse

sum with no matching values results in NPE on reverse ----------------------------------------------------- Key: JBRULES-3466 URL: https://issues.jboss.org/browse/JBRULES-3466 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Components: drools-core (expert) Affects Versions: 5.4.0.CR1 Environment: drools-planner 5.4.0-SNAPSHOT, snapshot downloaded on Apr 9, 2012 Reporter: Chris Dolan Assignee: Edson Tirelli I have a rule with this element in the when clause: {noformat} $beforePrediction : Number() from accumulate( JobSlot(job != NULL_JOB, $j : job, $service == service, $ordinal > ordinal) and $p : Prediction(job == $j, service == $service), sum($p.getMillisMid()) ) {noformat} When I execute this I have cases where there are no matching Prediction instances, so the sum is zero. Later on retract, I get this: {noformat} Caused by: java.lang.NullPointerException: null at org.drools.base.accumulators.SumAccumulateFunction.reverse(SumAccumulateFunction.java:83) at org.drools.base.accumulators.JavaAccumulatorFunctionExecutor.reverse(JavaAccumulatorFunctionExecutor.java:130) at org.drools.rule.Accumulate.reverse(Accumulate.java:208) {noformat} The relevant code is this: {noformat} public void accumulate(Serializable context, Object value) { SumData data = (SumData) context; data.total += ((Number) value).doubleValue(); } {noformat} and this: {noformat} public void reverse(Object workingMemoryContext, Object context, Tuple leftTuple, InternalFactHandle handle, Declaration[] declarations, Declaration[] innerDeclarations, WorkingMemory workingMemory) throws Exception { final Object value = ((JavaAccumulatorFunctionContext) context).reverseSupport.remove( Integer.valueOf( handle.getId() ) ); this.function.reverse( ((JavaAccumulatorFunctionContext) context).context, value ); } {noformat} A breakpoint reveals that handle is a Prediction instance. Somehow that handle was not added to reverseSupport, apparently.