Fix segfault when calling getSolTime on infeasible model's solution (#1167)

Author: Joao-Dionisio

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Speed up MatrixExpr.sum(axis=...) via quicksum
 - Added structured_optimization_trace recipe for structured optimization progress tracking
 ### Fixed
+- getBestSol() now returns None for infeasible problems instead of a Solution with NULL pointer
 - all fundamental callbacks now raise an error if not implemented
 - Fixed the type of MatrixExpr.sum(axis=...) result from MatrixVariable to MatrixExpr.
 - Updated IIS result in PyiisfinderExec()

src/pyscipopt/scip.pxi

@@ -10651,7 +10651,10 @@ cdef class Model:
         Solution or None
 
         """
-        self._bestSol = Solution.create(self._scip, SCIPgetBestSol(self._scip))
+        cdef SCIP_SOL* _sol = SCIPgetBestSol(self._scip)
+        if _sol == NULL:
+            return None
+        self._bestSol = Solution.create(self._scip, _sol)
         return self._bestSol
 
     def getSolObjVal(self, Solution sol, original=True):
@@ -10694,6 +10697,8 @@ cdef class Model:
         float
 
         """
+        if sol is None or sol.sol == NULL:
+            raise ValueError("Cannot get solution time: solution is None or NULL")
         return SCIPgetSolTime(self._scip, sol.sol)
 
     def getObjVal(self, original=True):

tests/test_solution.py

@@ -127,6 +127,25 @@ def test_getSolTime():
         assert m.getSolTime(s) >= 0
 
 
+def test_getBestSol_infeasible():
+    """Test that getBestSol returns None for infeasible problems instead of segfaulting."""
+    m = Model()
+    m.hideOutput()
+
+    x = m.addVar(ub=2)
+    m.addCons(x >= 4)  # infeasible: x <= 2 but x >= 4
+
+    m.optimize()
+
+    assert m.getStatus() == "infeasible"
+    sol = m.getBestSol()
+    assert sol is None
+
+    # getSolTime should raise ValueError for None solution
+    with pytest.raises(ValueError):
+        m.getSolTime(sol)
+
+
 def test_hasPrimalRay():
     m = Model()
     x = m.addVar()