[jboss-jira] [JBoss JIRA] (DROOLS-236) NPE when ksession is serialized with facts logically inserted

[RH Bugzilla Integration (JIRA)]

    [ https://issues.jboss.org/browse/DROOLS-236?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12803850#comment-12803850 ] 

RH Bugzilla Integration commented on DROOLS-236:
------------------------------------------------

Marek Winkler <mwinkler at redhat.com> made a comment on [bug 1000385|https://bugzilla.redhat.com/show_bug.cgi?id=1000385]

Verified on 5.3.1.BRMS-P04.
                
> NPE when ksession is serialized with facts logically inserted
> -------------------------------------------------------------
>
>                 Key: DROOLS-236
>                 URL: https://issues.jboss.org/browse/DROOLS-236
>             Project: Drools
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>    Affects Versions: 6.0.0.CR1
>            Reporter: Toshiya Kobayashi
>            Assignee: Edson Tirelli
>
> Reproduce steps:
> Assuming Employee is a subclass of Person...
> 1. Insert an Employee (say, 'Alice')
> 2. InsertLogical a Person (say, 'Bob')
> 3. Serialize and deserialize ksession
> 4. Insert an Employee (say, 'Claire')
> 5. Update 'Claire'
> It throws an NEP:
> {noformat}
> Exception executing consequence for rule "Promote" in defaultpkg: java.lang.NullPointerException
> 	at org.drools.core.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
> 	at org.drools.core.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1026)
> ...
> Caused by: java.lang.NullPointerException
> 	at org.drools.core.common.NamedEntryPoint.update(NamedEntryPoint.java:434)
> 	at org.drools.core.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:367)
> 	at defaultpkg.Rule_Promote139773612.defaultConsequence(Rule_Promote139773612.java:9)
> 	at defaultpkg.Rule_Promote139773612DefaultConsequenceInvokerGenerated.evaluate(Unknown Source)
> 	at defaultpkg.Rule_Promote139773612DefaultConsequenceInvoker.evaluate(Unknown Source)
> 	at org.drools.core.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1016)
> 	... 37 more
> {noformat}
> In the step 2, ClassObjectTypeConf of Person[Bob] enables TMS. But at that time, Employee[Alice] creates its EqualityKey and put it to TMS.
> NamedEntryPoint.java:
> {code:java}
>     private void enableTMS(Object object, ObjectTypeConf conf) {
>         
>         final Rete source = this.ruleBase.getRete();
>         final ClassObjectType cot = new ClassObjectType( object.getClass() );
>         final Map<ObjectType, ObjectTypeNode> map = source.getObjectTypeNodes( EntryPointId.DEFAULT );
>         final ObjectTypeNode node = map.get( cot );
>         final ObjectHashSet memory = ((ObjectTypeNodeMemory) this.wm.getNodeMemory( node )).memory;
>       
>         // All objects of this type that are already there were certainly stated,
>         // since this method call happens at the first logical insert, for any given type.
>         org.drools.core.util.Iterator it = memory.iterator();
>         for ( Object obj = it.next(); obj != null; obj = it.next() ) {
>           
>             org.drools.core.util.ObjectHashSet.ObjectEntry holder = (org.drools.core.util.ObjectHashSet.ObjectEntry) obj;
>     
>             InternalFactHandle handle = (InternalFactHandle) holder.getValue();
>             
>             if ( handle != null) {
>                 EqualityKey key = new EqualityKey( handle );
>                 handle.setEqualityKey( key );
>                 key.setStatus(EqualityKey.STATED);
>                 getTruthMaintenanceSystem().put(key);
>             }
>         }
>       
>         // Enable TMS for this type.
>         conf.enableTMS();
>       
>     }
> {code}
> Then during deserialization, ProtobufInputMarshaller enables TMS for ClassObjectTypeConf of Employee[Alice] and ClassObjectTypeConf of Person[Bob]. 
> ProtobufInputMarshaller.java:
> {code:java}
>     public static void readTruthMaintenanceSystem( MarshallerReaderContext context, 
>                                                    RuleData _session ) throws IOException {
>         TruthMaintenanceSystem tms = context.wm.getTruthMaintenanceSystem();
>         ProtobufMessages.TruthMaintenanceSystem _tms = _session.getTms();
>         
>         for( ProtobufMessages.EqualityKey _key : _tms.getKeyList() ) {
>             InternalFactHandle handle = (InternalFactHandle) context.handles.get( _key.getHandleId() );
>             // ObjectTypeConf state is not marshalled, so it needs to be re-determined
>             ObjectTypeConf typeConf = context.wm.getObjectTypeConfigurationRegistry().getObjectTypeConf( ((NamedEntryPoint)handle.getEntryPoint()).getEntryPoint(),
>                                                                                                          handle.getObject() );
>             if (!typeConf.isTMSEnabled()) {
>                 typeConf.enableTMS();
>             }
> {code}
> Finally, Employee(Claire) is updated. ClassObjectTypeConf of Employee is under TMS but Claire doesn't have EqualityKey hence NPE is thrown.

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