[jboss-jira] [JBoss JIRA] Commented: (JBRULES-2887) AccumulateNode runs into NPE

[Wolfgang Laun (JIRA)]

    [ https://issues.jboss.org/browse/JBRULES-2887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12580417#comment-12580417 ] 

Wolfgang Laun commented on JBRULES-2887:
----------------------------------------

The NPE can be avoided by testing accctx != null in retractLeftTuple and avoid calling removePreviousMatchesForLeftTuple and executing the if statement. But this method calls other methods, and it's not clear to me whether this would skip some essential activity. 

Also, it could be that the returned value shouldn't be null at all, and so s.th. else is broken.


> AccumulateNode runs into NPE
> ----------------------------
>
>                 Key: JBRULES-2887
>                 URL: https://issues.jboss.org/browse/JBRULES-2887
>             Project: Drools
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: drools-core
>    Affects Versions: 5.1.1.FINAL
>            Reporter: Wolfgang Laun
>            Assignee: Mark Proctor
>             Fix For: 5.2.0.M1
>
>
> A rule such as
> rule "average"
> when
>     B( id < 10 )
>     $list: List() from collect ( A() over window:time(10s) )
>            Number( $avg: doubleValue ) from accumulate( A( $id : id ) from $list, average( $id ) )
> then
>     System.out.println( "average = " + $avg );
> end
> runs into a NPE
> Caused by: java.lang.NullPointerException
> 	at org.drools.reteoo.AccumulateNode.getFirstMatch(AccumulateNode.java:967)
> 	at org.drools.reteoo.AccumulateNode.splitList(AccumulateNode.java:920)
> 	at org.drools.reteoo.AccumulateNode.removePreviousMatchesForLeftTuple(AccumulateNode.java:874)
> 	at org.drools.reteoo.AccumulateNode.retractLeftTuple(AccumulateNode.java:205)
> 	at org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateRetractLeftTuple(CompositeLeftTupleSinkAdapter.java:238)
> 	at org.drools.reteoo.CompositeLeftTupleSinkAdapter.propagateRetractLeftTupleDestroyRightTuple(CompositeLeftTupleSinkAdapter.java:138)
> 	at org.drools.reteoo.AccumulateNode.retractLeftTuple(AccumulateNode.java:212)
> 	at org.drools.reteoo.ModifyPreviousTuples.retractTuples(ModifyPreviousTuples.java:111)
> 	at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:176)
> 	at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:450)
> 	at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:361)
> 	at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:183)
> 	at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:196)
> 	at event.Rule_launch_0.defaultConsequence(Rule_launch_0.java:7)
> 	at event.Rule_launch_0DefaultConsequenceInvoker.evaluate(Rule_launch_0DefaultConsequenceInvoker.java:33)
> 	at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:913)
> A null Parameter accctx is passed down from retractLeftTuple. 

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