[rules-dev] Bug: package visibility - getter not recognized at fact insertion time (!)

[Wolfgang Laun]

PLEASE READ CAREFULLY, AND UNTIL THE END.

These two files (foo/Foo.java, foo/foo.drl) are sufficient to
reproduce the bug, i.e., a diagnostic
Exception in thread "main" [Error: could not access field: named.NamedEntity.x]
[Near : {... x == 1 ....}]
             ^
followed by a hefty stack dump due to an insert of a Foo.

package foo;
/*** not public ***/ class Foo {
    private int x = 1;
    public int getX(){ return x; }
}

package foo;
rule "foo getX"
when
    Foo( x == 1 )
then
    System.out.println( "some Foo.x == 1" );
end

But note that the problem goes a little deeper. Remove the constraint,
and the rule fires:

rule "some Foo"
when
    $foo: Foo()
then
   System.out.println( "some Foo..." );  // works perfectly
end

But now try to print the matched Foo:

rule "show all Foo factss"
when
    $foo: Foo()
then
   System.out.println( "Foo: " +  $foo );
end

Another dump:

Exception in thread "main" java.lang.IllegalAccessError: tried to
access class named.NamedEntity from class
named.Rule_xxx_fd3f0f5f764b415691fbf49ce4def6d7DefaultConsequenceInvokerGenerated
	at named.Rule_xxx_fd3f0f5f764b415691fbf49ce4def6d7DefaultConsequenceInvokerGenerated.evaluate(Unknown
Source)
	at named.Rule_xxx_fd3f0f5f764b415691fbf49ce4def6d7DefaultConsequenceInvoker.evaluate(Unknown
Source)
	at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287)
	at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1221)
	at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1456)
	at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:710)
	at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:674)
	at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:230)
	at named.Main.execute(Main.java:83)

I DO understand why this happens (so please DON'T explain it to me).

HOWEVER, IF PACKAGE VISIBILITY CANNOT BE HANDLED (and I don't think it
can), IT SHOULD BE REFUTED WITH A PROPER DIAGNOSTIC.

-W