[jboss-jira] [JBoss JIRA] (DROOLS-4909) Infinite recursion in drools after version change from v7.20 to v7.21
Mario Fusco (Jira)
issues at jboss.org
Wed Jan 8 09:35:21 EST 2020
[ https://issues.redhat.com/browse/DROOLS-4909?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Mario Fusco resolved DROOLS-4909.
---------------------------------
Resolution: Explained
Drools calculates the property reactivity of a pattern from the constraints used in that pattern. In case it is not able to figure out which property a constraint is impacting it takes the safest possible choice disabling the property reactivity for the whole pattern. To do this it analyzes the left part of a constraint (this is a known limitation) so in this sense
{code}
$card == card
{code}
and
{code}
card == $card
{code}
are not equivalent. In the first case Drools looks for a property named '$card' in the Metric object and since it cannot find any it disables the property reactivity for that pattern. Replace the first with the second in your drl and it will work as expected.
> Infinite recursion in drools after version change from v7.20 to v7.21
> ---------------------------------------------------------------------
>
> Key: DROOLS-4909
> URL: https://issues.redhat.com/browse/DROOLS-4909
> Project: Drools
> Issue Type: Bug
> Components: core engine
> Affects Versions: 7.21.0.Final, 7.22.0.Final, 7.23.0.Final, 7.25.0.Final, 7.31.0.Final
> Environment: Both Mac and Windows
> Reporter: Crosson David
> Assignee: Mario Fusco
> Priority: Major
> Attachments: Screen Shot 2019-07-10 at 3.53.10 PM.png, Screen Shot 2019-07-10 at 5.56.32 PM.png, Screen Shot 2019-07-10 at 5.59.28 PM.png, error.png, pojo.png, static.png, static_error.png, toto.drl
>
>
> 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|https://github.com/padippist/DroolsIssueReporting/tree/issue_v_7.20]
> [The recursively looping version|https://github.com/padippist/DroolsIssueReporting/tree/issue_v_7.21]
> [The change between working and looping version|https://github.com/padippist/DroolsIssueReporting/compare/issue_v_7.20...issue_v_7.21]
> *More details*
> When I fire a rule whose `then` part modifies a fact that is already checked in the `when` part:
> {code:java}
> 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
> {code}
> it doesn't loop recursively.
> But when I call another rule which call a static function from another class:
> {code:java}
> rule "rule 1.2"
> when
> $sampleDomain: SampleDomain(CoreUtils.anotherFunction())
> then
> System.out.println("Rule 1.2 fired");
> modify($sampleDomain){
> setInstanceVariable1(3)
> }
> end
> {code}
> it loops recursively.
> The class with static function is
> {code:java}
> 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;
> }
> }
> {code}
> My domain file is:
> {code:java}
> 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;
> }
>
>
> }
> {code}
> 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
> {code:java}
> public boolean anotherFunction() {
> return true;
> }
>
> public boolean anotherFunction(SampleDomain sampleDomain) {
> return true;
> }
> {code}
> and use this in the rule like:
> {code:java}
> rule "rule 1.4"
> when
> $sampleDomain: SampleDomain(anotherFunction())
> then
> System.out.println("Rule 1.4 fired");
> modify($sampleDomain){
> setInstanceVariable1(3)
> }
> end
> {code}
> and
> {code:java}
> rule "rule 1.5"
> when
> $sampleDomain: SampleDomain(anotherFunction($sampleDomain))
> then
> System.out.println("Rule 1.5 fired");
> modify($sampleDomain){
> setInstanceVariable3(4)
> }
> end
> {code}
> these also loops recursively.
> *Code in github:*
> [The recursive looping when using non static methods|https://github.com/padippist/DroolsIssueReporting/tree/issue_v_7.20_non_static_methodes]
> [The change between working and above version|https://github.com/padippist/DroolsIssueReporting/compare/issue_v_7.20...issue_v_7.20_non_static_methodes]
> 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.|https://github.com/padippist/DroolsIssueReporting/blob/bde2804b250babf11cf5d3cf48640d9e6c88f5b3/src/main/resources/rules/rule1.drl#L21]
> [Another rule which also call the static method.|https://github.com/padippist/DroolsIssueReporting/blob/bde2804b250babf11cf5d3cf48640d9e6c88f5b3/src/main/resources/rules/rule1.drl#L32]
> [The static access modifier removed from the functions which where previously static.|https://github.com/padippist/DroolsIssueReporting/compare/issue_v_7.20...issue_v_7.21_weird_behaviors#diff-4e0f238b1184e2267cb5663b9afeaa6fL7]
> *Code in github:*
> [Weird behaviour when removing static modifier for the functions.|https://github.com/padippist/DroolsIssueReporting/tree/issue_v_7.21_weird_behaviors]
> [The change between working and above version|https://github.com/padippist/DroolsIssueReporting/compare/issue_v_7.20...issue_v_7.21_weird_behaviors]
> *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`*
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