[jboss-jira] [JBoss JIRA] (DROOLS-577) Filter doesn't work if object has "rule" as a fieldname

[Edson Tirelli (JIRA)]

    [ https://issues.jboss.org/browse/DROOLS-577?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13099891#comment-13099891 ] 

Edson Tirelli commented on DROOLS-577:
--------------------------------------

A few additional thoughts on this issue:


* currently, the same context is used for MVEL parsing/compilation everywhere on the engine. For instance, the same context is used to parse/compile an "enabled" expression on the rule and also pattern constraints:

{code:title=snippet.drl|borderStyle=solid}
    rule X 
        enabled( rule.name == "X" )  // here rule refers to the actual rule
    when
        Fired( rule == "some rule name" ) // here rule is an attribute of the Fired class
    ...
{code}

* The MVEL parser/compiler is treating both as "external identifiers" that would be injected at runtime. This is correct for the "enabled" expression, but not for the constraint.

* We can not inject the "rule" object into constraints, because constraints can be shared by multiple rules.

* Therefore, the solution seems to be to use different contexts when parsing/compiling mvel expressions. When compiling things like the "enabled" expression, we list/inject "rule" as a known identifier for the rule object itself. When compiling constraints, we do not inject "rule" as a known identifier and let it be resolved to the attribute itself.


> Filter doesn't work if object has "rule" as a fieldname
> -------------------------------------------------------
>
>                 Key: DROOLS-577
>                 URL: https://issues.jboss.org/browse/DROOLS-577
>             Project: Drools
>          Issue Type: Bug
>    Affects Versions: 6.1.0.Final
>            Reporter: Wayne Price
>            Assignee: Edson Tirelli
>            Priority: Minor
>
> Engine seems not find objects when trying to filter based on a field name "rule".



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