[rules-dev] [BAD Bug] incorrect evaluation of LHS using Integer/Number intValue

[Wolfgang Laun]

[Sorry - the previous email "escaped" before I was complete.]

This is a self-contained DRL demonstrating the erroneous handling of
a condition involving Integer.intValue (same: Number.intValue), not
and retract, which is meant to sort the integers. This fails with 5.5.0,
but works correctly with 5.4.0 and previous versions.

rule init
salience 9999
when
then
    insert( Integer.valueOf( 10 ) );
    insert( Integer.valueOf( 50 ) );
    insert( Integer.valueOf( 60 ) );
    insert( Integer.valueOf( 40 ) );
    insert( Integer.valueOf( 20 ) );
end

rule "Rule 04"
when
    $number : Integer( $i: intValue )
    not Integer(intValue < $i)
then
    System.out.println("Number found with value: " + $number.intValue());
    retract($number);
end

>
> On 17/01/2013, Wolfgang Laun <wolfgang.laun at gmail.com> wrote:
>> This BAD bug was introduced on the way from 5.4.0 to 5.5.0 (and seems
>> to have sneaked into 6.0.0 as well).
>>
>> Only 5.4.0 and predecessors work as expected.
>>
>> Damage control? How far can 5.5.0 be trusted?
>>
>>
>> On 17/01/2013, John Smith <ffirstt.llastt at gmail.com> wrote:
>>> I am new to Drools and am trying to get the sample program to work. This
>>> sample is given in the drools documentation
>>> http://docs.jboss.org/drools/release/5.5.0.Final/drools-expert-docs/html_single/index.html#d0e9542.
>>> This drool rule is expected to sort integers. I just changed the numbers
>>> from what are given in the sample and they do not get sorted as
>>> expected.
>>> Tried using drools version 5.5.0, 5.5.1 and the master 6.0.0, but got
>>> the
>>> same wrong results.
>>>
>>> Following is the main code:
>>>     package com.sample;
>>>
>>>     public class Example2 {
>>>       public static void main(String[] args) throws Exception {
>>>         Number[] numbers = new Number[] { wrap(5), wrap(6), wrap(4),
>>> wrap(1), wrap(2) };
>>>         new RuleRunner().runRules(new String[] { "Example3.drl" },
>>> numbers);
>>>       }
>>>
>>>       private static Integer wrap(int i) {
>>>         return new Integer(i);
>>>       }
>>>     }
>>>
>>>  The RuleRunner class is the same as given in the example and I do not
>>> think
>>> I should give that here, since it will clutter the question. It simply
>>> creates the KnowledgeBase, stateful session, inserts the facts as given
>>> in
>>> the 'numbers' array above and then calls fireAllRules method on the
>>> session.
>>>
>>> The rule file (Example3.drl) is:
>>>
>>>
>>>  rule "Rule 04"
>>>      dialect "mvel"
>>>    when
>>>      $number : Number()
>>>      not Number(intValue < $number.intValue)
>>>    then
>>>      System.out.println("Number found with value: " +
>>> $number.intValue());
>>>      retract($number);
>>>  end
>>>
>>>
>>> The output I get is as follows:
>>> Loading file: Example3.drl
>>> Inserting fact: 5
>>> Inserting fact: 6
>>> Inserting fact: 4
>>> Inserting fact: 1
>>> Inserting fact: 2
>>> Number found with value: 1
>>> Number found with value: 4
>>> Number found with value: 2
>>> Number found with value: 5
>>> Number found with value: 6
>>>
>>> Not the correct expected ascending sorted order.
>>>
>>> What might I be doing wrong? I cannot imagine that the drools rule
>>> engine
>>> would be broken at this basic level.
>>>
>>>
>>>
>>> --
>>> View this message in context:
>>> http://drools.46999.n3.nabble.com/Drools-Expert-does-not-sort-integers-correctly-tp4021606.html
>>> Sent from the Drools: User forum mailing list archive at Nabble.com.
>>> _______________________________________________
>>> rules-users mailing list
>>> rules-users at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>>
>>
>