[jboss-jira] [JBoss JIRA] (DROOLS-5449) ClassCastException upon unreferenced declare update

[Mario Fusco (Jira)]

    [ https://issues.redhat.com/browse/DROOLS-5449?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14180931#comment-14180931 ] 

Mario Fusco commented on DROOLS-5449:
-------------------------------------

[~mcasalino] I understand that this behavior is misleading. It is caused by the fact that the problem gets triggered only after the engine have attempted to transform the mvel interpreted constraint into a java class for faster evaluation. I could maybe prevent this problem by checking if you're using the "right" FactType and throw an early error (or warning) in case you are not. However this additional check would be a useless waste of time in 99.9...% of cases and for this reason I'd prefer to avoid it. I hope you agree. Also consider that using the executable model you shouldn't have this issue.

> ClassCastException upon unreferenced declare update
> ---------------------------------------------------
>
>                 Key: DROOLS-5449
>                 URL: https://issues.redhat.com/browse/DROOLS-5449
>             Project: Drools
>          Issue Type: Bug
>          Components: core engine
>    Affects Versions: 7.38.0.Final
>            Reporter: Matteo Casalino
>            Assignee: Mario Fusco
>            Priority: Major
>         Attachments: class-cast-exception-on-unreferenced-declare-update.zip
>
>
> After updating a declared type that is not referenced in the rules with _updateToVersion()_,
>  running _fireAllRules()_ many times in a loop throws _ClassCastException_.
> E.g., when the following DRL:
> {noformat}
> declare UnreferencedType
>  x : int
> end 
> declare ReferencedType
>  str : String
> end
>  
> rule "example rule"
> when
>  ReferencedType( str == "A" )
> then
> end{noformat}
> is updated to:
> {noformat}
> declare UnreferencedType
>  x : int
>  newField : String
> end 
> declare ReferencedType
>  str : String
> end
>  
> rule "example rule"
> when
>  ReferencedType( str == "A" )
> then
> end{noformat}
> the following exception it thrown by _fireAllRules()_:
> {noformat}
> java.lang.RuntimeException: Error evaluating constraint 'str == "A"' in [Rule "example rule" in org/example/rules.drl]
>  at org.drools.core.rule.constraint.MvelConstraint.evaluate(MvelConstraint.java:277)
>  at org.drools.core.rule.constraint.MvelConstraint.isAllowed(MvelConstraint.java:225)
>  at org.drools.core.reteoo.AlphaNode.assertObject(AlphaNode.java:139)
>  ...
>  Caused by: java.lang.ClassCastException: class org.example.ReferencedType cannot be cast to class org.example.ReferencedType (org.example.ReferencedType is in unnamed module of loader org.drools.dynamic.DynamicProjectClassLoader$DefaultInternalTypesClassLoader @46292372; org.example.ReferencedType is in unnamed module of loader org.drools.dynamic.DynamicProjectClassLoader$DefaultInternalTypesClassLoader @23b8d9f3)
>  at ConditionEvaluator7ed8b2c57cad4e74b856fdba30554aa1.evaluate(Unknown Source)
>  at org.drools.core.rule.constraint.MvelConstraint.evaluate(MvelConstraint.java:275)
>  ... 43 more{noformat}



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