potassco / potassco/constraint-handler

Difference in treatment of None for conj/disj in compile and propagator engines

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Python
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Description

When None is used in the conj/disj operators the compile engine has different behaviour to the propagator(evaluator.py). This can be seen in the "datatype/bool/conj_disj_mixed" test. Here is another example:

variable_define(result, operation(limp,(operation(conj,(operation(lnot,(variable(a),())),(variable(b),()))),(val(bool,false),())))).
variable_define(a, val(none,none)).
variable_define(b, val(bool,true)).

Compile result: bad
Propagator result: None

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Research direction

Start with the datatype/bool/conj_disj_mixed test and evaluator.py, then reproduce the supplied example in both the compile and propagator engines. Compare how None is handled by conj/disj and identify the intended consistent result. Done means the engines agree and the mixed-value test covers the regression.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
backend
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
68/100

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