gh-145044: avoid calling Py_DECREF in unsafe_object_compare on immortal objects (#145045)

benediktjohannes · web-flow · commit 50f82d062b3b · 2026-03-10T22:03:56.000+05:30
diff --git a/Objects/listobject.c b/Objects/listobject.c
@@ -2795,11 +2795,12 @@ unsafe_object_compare(PyObject *v, PyObject *w, MergeState *ms)
 
     if (PyBool_Check(res_obj)) {
         res = (res_obj == Py_True);
+        assert(_Py_IsImmortal(res_obj));
     }
     else {
         res = PyObject_IsTrue(res_obj);
+        Py_DECREF(res_obj);
     }
-    Py_DECREF(res_obj);
 
     /* Note that we can't assert
      *     res == PyObject_RichCompareBool(v, w, Py_LT);

Original file line number	Diff line number	Diff line change
`@@ -2795,11 +2795,12 @@ unsafe_object_compare(PyObject v, PyObject w, MergeState *ms)`
`2795`	`2795`
`2796`	`2796`	`if (PyBool_Check(res_obj)) {`
`2797`	`2797`	`res = (res_obj == Py_True);`
	`2798`	`+ assert(_Py_IsImmortal(res_obj));`
`2798`	`2799`	`}`
`2799`	`2800`	`else {`
`2800`	`2801`	`res = PyObject_IsTrue(res_obj);`
	`2802`	`+ Py_DECREF(res_obj);`
`2801`	`2803`	`}`
`2802`		`- Py_DECREF(res_obj);`
`2803`	`2804`
`2804`	`2805`	`/* Note that we can't assert`
`2805`	`2806`	`* res == PyObject_RichCompareBool(v, w, Py_LT);`