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Type: Bug
Resolution: Not a Bug
Priority: Major
Fix Version/s: None
Affects Version/s: 7.21.0.Final, 7.22.0.Final, 7.23.0.Final, 7.25.0.Final, 7.31.0.Final
Component/s: core engine
Labels:
None

Sprint:
2020 Week 01-03 (from Dec 30)
Steps to Reproduce:

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Docs QE Status:
NEW
QE Status:
NEW

https://issues.redhat.com/browse/DROOLS-4288

The problem is not fully solved, I got a forever loop on my KB since 7.21.0.Final, I tried with 7.25.0.Final but without success, and the issue is still here with 7.31.0.Final. Will go back to release 7.20.0.Final
(the only fix I can apply is to add no-loop clause to my rules although it shouldn't be necessary).

I can't share the affected KB, and unfortunately I was unable to reproduce the issue loop on a smaller example

The affected rule looks like :

{{rule "reset metric to max score when no more issues are present"
//no-loop // TODO - no-loop TO BE REMOVED AS IT SHOULDN'T BE NECESSARY
when
Something($id:identity, $origin:origin)
not Issue($id == identity, $origin == origin, category!="metrics")
$scoring: Scoring(name == "performance", $id == identity, $origin == origin)
then
modify($scoring)

{ setValue(100.0); }

end}}

from https://issues.redhat.com/browse/DROOLS-4288 :

When there is a version change in drools-compiler from `7.20.0.Final` to `7.21.0.Final` some rules are looping recursively.

Code in github:

The working version

The recursively looping version

The change between working and looping version

More details

When I fire a rule whose `then` part modifies a fact that is already checked in the `when` part:

rule "rule 1.1"
  when
    $sampleDomain: SampleDomain(instanceVariable2 == "Value of instance variable")
  then
    System.out.println("Rule 1.1 fired");
    modify($sampleDomain){
    		setInstanceVariable1(3)
    }
end

it doesn't loop recursively.

But when I call another rule which call a static function from another class:

rule "rule 1.2"
  when
    $sampleDomain: SampleDomain(CoreUtils.anotherFunction())
  then
    System.out.println("Rule 1.2 fired");
    modify($sampleDomain){
    		setInstanceVariable1(3)
    }
end

it loops recursively.

The class with static function is

import com.drool_issue.domain.SampleDomain;

public class CoreUtils {
	
	public static boolean anotherFunction() {
		System.out.println("anotherFunction() inside CoreUtils");
		return true;
	}
	
	public static boolean anotherFunction(SampleDomain sampleDomain) {
		System.out.println("anotherFunction(SampleDomain sampleDomain) inside CoreUtils");
		return true;
	}

}

My domain file is:

public class SampleDomain {
	private int instanceVariable1;
	private String instanceVariable2;
	private int instanceVariable3;
	
	
	public int getInstanceVariable1() {
		return instanceVariable1;
	}
	public void setInstanceVariable1(int instanceVariable1) {
		this.instanceVariable1 = instanceVariable1;
	}
	public String getInstanceVariable2() {
		return instanceVariable2;
	}
	public void setInstanceVariable2(String instanceVariable2) {
		this.instanceVariable2 = instanceVariable2;
	}
	public int getInstanceVariable3() {
		return instanceVariable3;
	}
	public void setInstanceVariable3(int instanceVariable3) {
		this.instanceVariable3 = instanceVariable3;
	}
	
	

}

This is only caused after version change from `7.20.0.Final` to `7.21.0.Final`. Any guess on what the problem might be?

When I further looked into the problem I saw this too.

When we add two functions into the `SampleDomain` class ie

    public boolean anotherFunction() {
		return true;
	}
	
	public boolean anotherFunction(SampleDomain sampleDomain) {
		return true;
	}

and use this in the rule like:

rule "rule 1.4"
  when
    $sampleDomain: SampleDomain(anotherFunction())
  then
    System.out.println("Rule 1.4 fired");
    modify($sampleDomain){
    		setInstanceVariable1(3)
    }
end

and

rule "rule 1.5"
  when
    $sampleDomain: SampleDomain(anotherFunction($sampleDomain))
  then
    System.out.println("Rule 1.5 fired");
    modify($sampleDomain){
    		setInstanceVariable3(4)
    }
end

these also loops recursively.

Code in github:

The recursive looping when using non static methods

The change between working and above version

Also when any of the static method is made non static then method from the domain class is called even though the static method is specified in the rule.

Code portions to be noted here are:

Rule where static method is called.

Another rule which also call the static method.

The static access modifier removed from the functions which where previously static.

Code in github:

Weird behaviour when removing static modifier for the functions.

The change between working and above version

All this are caused in versions after `7.20.0.Final`, ie `7.21.0.Final`, `7.22.0.Final` and `7.23.0.Final`