[jboss-jira] [JBoss JIRA] (DROOLS-551) Incorrect serialization of Drools STREAM KieSession with expirable events causes NPE

[Duncan Doyle (JIRA)]

Duncan Doyle created DROOLS-551:
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             Summary: Incorrect serialization of Drools STREAM KieSession with expirable events causes NPE
                 Key: DROOLS-551
                 URL: https://issues.jboss.org/browse/DROOLS-551
             Project: Drools
          Issue Type: Bug
      Security Level: Public (Everyone can see)
    Affects Versions: 6.1.0.CR2
         Environment: Mac OS X 10.9.2, Oracle HotSpot 1.7.0_60, JBoss BRMS 6.0.2.GA
            Reporter: Duncan Doyle
            Assignee: Mark Proctor
            Priority: Critical


There is an issue in Drools 6, both in PHREAK and RETEOO mode, which causes NPEs to be thrown when a session is serialized and deserialized.
The problem occurs when running a stateful KieSession in STREAM mode and using Events with @expires annotations.
When you insert an event with an @expires annotation, and you explicitly retract that Event again from the engine (i.e. KieSession.delete), 
and after that serialize the session, you end up with an invalid serialized session.

When you later deserialize the session, and immediately serialize it again, a NPE is thrown at: org.drools.core.reteoo.ObjectTypeNode$ExpireJobContextTimerOutputMarshaller.serialize(ObjectTypeNode.java:669)
When you deserialize the session and then advance the pseudo clock to a moment where the original event (which we've already retracted from the working memory) should have expired,
a NPE is thrown at: org.drools.core.common.AbstractWorkingMemory$WorkingMemoryReteExpireAction.execute(AbstractWorkingMemory.java:1524)

So, it seems that when the Event is explicitly retracted with KieSesion.delete(event), the event is removed from the WM, but the Expiry Timer Job is not. That ExpiryJob gets 
serialized with a 'null' fact hanle, which does not give issues on de-serialization, but on the next serialization of the session, or when an action is peformed that triggers
the expire action (i.e. move the pseudo-clock).

A reproducer can be  found here: http://www.github.com/DuncanDoyle/DroolsSerializationIssue . To reproduce:
- git clone http://www.github.com/DuncanDoyle/DroolsSerializationIssue
- cd DroolsSerializationIssue/DroolSerializationIssue
- mvn clean test -P phreak	(runs the test with Drools in PHREAK mode)
- mvn clean test -P reteoo 	(runs the test with Drools in RETEOO mode)

In both modes 2 of the 3 tests produce an NPE.

Cheers,

Duncan



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