[jboss-jira] [JBoss JIRA] Commented: (JBRULES-2482) Binding seems to be unreliable with MVEL dialect and mulitple evals

[Edson Tirelli (JIRA)]

    [ https://jira.jboss.org/browse/JBRULES-2482?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12532620#action_12532620 ] 

Edson Tirelli commented on JBRULES-2482:
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Hi Chris, thanks for reporting and providing test case. 

Unfortunately the problem is not the offset vs index thing. Index is just an arbitrary sequential number assigned according to the order in which Patterns are written in a given rule. Offset, on the other hand, corresponds to the actual position of an object matching that pattern inside a tuple. So offset must be used when resolving declarations against objects in a given tuple. 

Debugging the problem I found that contrary to the java dialect, the mvel dialect is caching Declaration instances. It happens, though, that when a rule contains an "or" statement (and in a few other cases), declarations must be cloned and updated. That was happening for regular constraints, but not for eval expressions. That is not a problem for the java dialect because it does not cache declarations, but it is a problem for the mvel dialect for the same reason. 

I am fixing this now.


> Binding seems to be unreliable with MVEL dialect and mulitple evals
> -------------------------------------------------------------------
>
>                 Key: JBRULES-2482
>                 URL: https://jira.jboss.org/browse/JBRULES-2482
>             Project: Drools
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: drools-core  (expert)
>    Affects Versions: 5.1.0.M1
>         Environment: Windows 7, Sun JDK 1.6.0_17
>            Reporter: Chris DeLashmutt
>            Assignee: Edson Tirelli
>         Attachments: mvel-binding-problem.zip, patch.txt.txt
>
>
> When using the MVEL dialect, a rule with multiple binds, and a chain of evals, the bindings seem to be incorrect.
> For example here is some DRL:
> rule "Modify Field Rule for Form: InterrelatedFieldsTestForm.fieldA (Set fieldA optional if values are in other fields)"
>     when
>         $fieldA: Field(id == "fieldA")
>         $fieldB: Field(id == "fieldB")
>         $fieldC: Field(id == "fieldC")
>         (eval(ValidationFunctions.isChecked($fieldA)) or eval(ValidationFunctions.isChecked($fieldB)) or eval(!ValidationFunctions.isBlank($fieldC))) 
>     then
>         ValidationFunctions.insertOperation(fieldOperations, new FieldOperation("fieldA",FieldOperation.OPTIONAL));
> end
> If I put debugging statements in to the static ValidationFunctions methods, or if I put breakpoints in those same static methods, I see invocations using bound variables that don't match what I declared.
> For instance, I'll see isBlank called with what appears to be the contents of $fieldA.
> If I combine the evals into a single eval with each condition separated by ||. everything seems to function properly.  I can't easily go back and change the syntax in my exisiting rules however, and the syntax I'm using seems to be valid based on my interpretation of the documentation.

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