Mukta13 commented on PR #6113:
URL: 
https://github.com/apache/incubator-kie-drools/pull/6113#issuecomment-2429201986

   Thanks for the reply! In my case:
   
   The error as stated in  Issue: 
https://github.com/apache/incubator-kie-drools/issues/6112 is rooted in 
non-deterministic behavior in the Drools rule execution due to the modify 
block. The modify($p) block combines fact ($p)changes and triggers rule 
re-evaluation of the rule automatically in the same step . Thus, the _timing_ 
of this re-evaluation can vary, causing inconsistent rule firing orders, 
leading to random test failures.  Because modify($p) triggers immediate 
re-evaluation of dependent rules, the order and timing of rule firing are 
varying. The critical point here is **when** the rule engine processes this 
re-evaluation. The modify block does not guarantee the order in which rules are 
re-triggered or when this happens during the rule evaluation cycle. This 
timing-related non-determinism  may fire other rules dependent on $p at 
unpredictable points during the execution, before $p has reached its final 
state. Thus, this timing related flaky test does not seem to be a false p
 ositive detected by the non-dex tool, which was detected by non-dex because 
this timing issue was also causing the non determinsim relating to the order of 
rule firings, as seen in the error.
   
   **How $p.setX() + update($p) instead of modify() fixes the Issue:**
   Switching from modify($p) to $p.setX() followed by update($p) effectively 
resolves the timing-related non-determinism in Drools rules execution. By 
separating the modification and the update, $p.setX() allows for controlled 
changes to the fact without triggering immediate re-evaluation (unlike seen in 
modify), which can lead to inconsistent rule firing sequences. The explicit 
update($p) then signals to the rule engine to reconsider the fact only after 
all modifications are complete, ensuring it is in its final, consistent state.  
This ensures that all rules that depend on the updated fact($p) behave 
consistently, thus, eliminating the **timing-related ordering non-determinism** 
that can arise with modify($p). 
   
   


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