gh-133548: fix handling of empty and 1-item tuples for sys.exit

[picnixz]

cc @markshannon@iritkatriel

• Issue: sys.exit unpacks its argument if it is a 0- or 1-element tuple #133548

[bedevere-bot]

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[iritkatriel]

Isn't this a problem with how PyErr_SetObject creates the exception? Shouldn't it be fixed there?

[picnixz]

I think it's a bit unfortunate because that's how _PyErr_CreateException handles tuples:

staticPyObject*_PyErr_CreateException(PyObject*exception_type, PyObject*value){PyObject*exc; if (value==NULL||value==Py_None){exc=_PyObject_CallNoArgs(exception_type)} elseif (PyTuple_Check(value)){exc=PyObject_Call(exception_type, value, NULL)} else{exc=PyObject_CallOneArg(exception_type, value)} if (exc!=NULL&& !PyExceptionInstance_Check(exc)){PyErr_Format(PyExc_TypeError, "calling %R should have returned an instance of ""BaseException, not %s", exception_type, Py_TYPE(exc)->tp_name); Py_CLEAR(exc)} returnexc}

Unless you want me to change _PyErr_CreateException to prevent the fast paths, it could be annoying for downstream users.

[iritkatriel]

It's not a "fast path" if removing it changes behaviour. We need to understand whether _PyErr_CreateException has a bug or not.

[picnixz]

I think it was designed as such for conveniency. It was added in 3a84097 but AFAICT, that was just refactoring of c0dc92a (1997) which already had this fast path.