[CP-SAT] fix #4568

ortools/sat/python/cp_model.py

@@ -2182,7 +2182,7 @@ class CpModel:
 
         # Raises TypeError if linear_expr is not an integer.
         flat_expr = cmh.FlatIntExpr(linear_expr)
-        result.offset = flat_expr.offset
+        result.offset = flat_expr.offset * mult
         for var in flat_expr.vars:
             result.vars.append(var.index)
         for coeff in flat_expr.coeffs:

ortools/sat/python/cp_model_test.py

@@ -1025,6 +1025,19 @@ class CpModelTest(absltest.TestCase):
         )
         self.assertTrue(passed)
 
+    def test_issue4568(self) -> None:
+        model = cp_model.CpModel()
+        target = 11
+        value = model.new_int_var(0, 10, "")
+        defect = model.new_int_var(0, cp_model.INT32_MAX, "")
+        model.add_abs_equality(defect, value - target)
+        model.minimize(defect)
+
+        solver = cp_model.CpSolver()
+        status = solver.Solve(model)
+        self.assertEqual(status, cp_model.OPTIMAL)
+        self.assertEqual(solver.objective_value, 1.0)
+
     def test_division(self) -> None:
         model = cp_model.CpModel()
         x = model.new_int_var(0, 10, "x")