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  1. Red Hat Decision Manager
  2. RHDM-1643

Inconsistent behavior when accumulate function returns null

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Details

    • Bug
    • Resolution: Done
    • 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.

    • 2
    • False
    • False
    • CR1
    • +
    • Undefined
    • Hide
      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)

    Description

      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.

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        Issue Links

          incorporates

          Bug - A problem that impairs or prevents the functions of the product. DROOLS-6064 Inconsistent behavior when accumulate function returns null

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Closed

          Activity

            People

              rhn-support-tkobayas Toshiya Kobayashi
              rhn-support-myoshida Masato Yoshida
              Daniel Rosa Daniel Rosa
              Daniel Rosa Daniel Rosa
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              Dates

                Created:
                Updated:
                Resolved: