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  1. Red Hat Decision Manager
  2. RHDM-1643

Inconsistent behavior when accumulate function returns null

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    • Icon: Bug Bug
    • Resolution: Done
    • Icon: Major Major
    • 7.11.0.GA
    • 7.9.1.GA, 7.10.0.GA
    • BRE

    • This issue was reported on RHDM 7.9.1.
      It is also reproducible on 7.10.0.

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      1. Extract the reproducer. 
        $ unzip reproducer_accumulate_test.zip
$ cd reproducer_accumulate_test
      2. Edit src/main/java/com/example/reproduccer/DroolsTest.java (Use either of the following lines) 
            // target.setText("XXX");
    target.setText("NoMatch");
      3. Build and run the reproducer. 
        $ ./run_mvn

        (1) the result when you use target.setText("XXX")

        $ ./run_mvn
    :
    :
***** start
***** accumualte_rule_min: $min = 10
***** accumualte_rule_max: $max = 10
***** accumualte_rule_minmax: $max = 10, $min = 10
***** accumualte_rule_average: $ave = 10.0
***** accumualte_rule_count: $count = 1
***** accumualte_rule_sum: $sum = 10
***** end
    :
    :

        (2) the result when you use target.setText("NoMatch")

        $ ./run_mvn
    :
    :
***** start
***** accumualte_rule_minmax: $max = null, $min = null
***** accumualte_rule_count: $count = 0
***** accumualte_rule_sum: $sum = 0
***** end
    :
    :
      Show
      Extract the reproducer. $ unzip reproducer_accumulate_test.zip $ cd reproducer_accumulate_test Edit src/main/java/com/example/reproduccer/DroolsTest.java (Use either of the following lines) // target.setText( "XXX" ); target.setText( "NoMatch" ); Build and run the reproducer. $ ./run_mvn (1) the result when you use target.setText("XXX") $ ./run_mvn : : ***** start ***** accumualte_rule_min: $min = 10 ***** accumualte_rule_max: $max = 10 ***** accumualte_rule_minmax: $max = 10, $min = 10 ***** accumualte_rule_average: $ave = 10.0 ***** accumualte_rule_count: $count = 1 ***** accumualte_rule_sum: $sum = 10 ***** end : : (2) the result when you use target.setText("NoMatch") $ ./run_mvn : : ***** start ***** accumualte_rule_minmax: $max = null, $min = null ***** accumualte_rule_count: $count = 0 ***** accumualte_rule_sum: $sum = 0 ***** end : :
    • 2021 Week 10-12 (from Mar 8), 2021 Week 13-15 (from Mar 29)

      When you use accumulate and no fact matches, the behaviors are different depending on accumulate functions:

          rule "accumualte_rule_min"
      when
        accumulate( target : Target( target.getText() == "XXX" ),
                    $min : min( target.getNumber1() ) )
      then
        System.out.println("***** accumualte_rule_min: $min = " + $min);
    end

      min() : IntegerMinAccumulateFunction -> returns null if no fact matches
      max() : IntegerMaxAccumulateFunction -> returns null if no fact matches
      ave() : AverageAccumulateFunction -> returns null if no fact matches

      -> If the result is null, the rule won't fire.

      https://github.com/kiegroup/drools/blob/master/drools-core/src/main/java/org/drools/core/phreak/PhreakAccumulateNode.java#L620-L627

      count() : CountAccumulateFunction -> returns 0 if no fact matches
      sum() : IntegerSumAccumulateFunction -> returns 0 if no fact matches

      -> result is not null. So the rule is fired.

      min(), max() : When you have multiple functions in accumulate, MultiAccumulate is used. This returns Object[] which contains multiple results. In this case, result = Object[2] which is [null, null].

      https://github.com/kiegroup/drools/blob/master/drools-core/src/main/java/org/drools/core/rule/MultiAccumulate.java#L163-L177

      -> In this case, the result is not null. So the rule is fired with these "null" results.

      This JIRA is to make it consistent.

        1. reproducer_accumulate_test.zip
          10 kB

              rhn-support-tkobayas Toshiya Kobayashi
              rhn-support-myoshida Masato Yoshida
              Daniel Rosa Daniel Rosa
              Daniel Rosa Daniel Rosa
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                Created:
                Updated:
                Resolved: