The use of `PyStackRef_AsPyObjectBorrow` makes it hard to track ownership of references, making analysis of escaping calls too difficult

The problem with PyStackRef_AsPyObjectBorrow is that it is not clear whether the reference is owned by the stack ref or the pointer.

Borrowing references across calls is fine but in less structured code, it is error prone and very hard to analyze.

The solution is change most, ideally all, uses of PyStackRef_AsPyObjectBorrow to PyStackRef_AsPyObjectSteal so that the ownership of the reference is clear.
E.g.

        inst(UNARY_NEGATIVE, (value -- res)) {
            PyObject *val_o = PyStackRef_AsPyObjectBorrow(value);
            PyObject *res_o = PyNumber_Negative(val_o);
            PyStackRef_CLOSE(value);
            ERROR_IF(res_o == NULL, error);
            res = PyStackRef_FromPyObjectSteal(res_o);
        }

would become:

        inst(UNARY_NEGATIVE, (value -- res)) {
            PyObject *val_o = PyStackRef_AsPyObjectSteal(value);
            PyObject *res_o = PyNumber_Negative(val_o);
            Py_DECREF(val_o);
            ERROR_IF(res_o == NULL, error);
            res = PyStackRef_FromPyObjectSteal(res_o);
        }

This ensures that during the escaping call to PyNumber_Negative, the reference to the value a PyObject *, so will not be reclaimed by the garbage collector.

Linked PRs

• gh-122037

Recherchez dans le code source de CPython les utilisations de PyStackRef_AsPyObjectBorrow et examinez les schémas d’ownership de PyStackRef_AsPyObjectSteal et PyStackRef_CLOSE présentés dans l’issue. Déterminez quelles utilisations traversent des appels lors desquels les références peuvent s’échapper, puis vérifiez que les références concernées restent valides et que l’ownership est explicite ; comparez le travail avec la PR liée gh-122037.