diff options
| -rw-r--r-- | Objects/abstract.c | 40 |
1 files changed, 23 insertions, 17 deletions
diff --git a/Objects/abstract.c b/Objects/abstract.c index dc8ba10..aca1a4e 100644 --- a/Objects/abstract.c +++ b/Objects/abstract.c @@ -2423,7 +2423,7 @@ check_class(PyObject *cls, const char *error) } static int -recursive_isinstance(PyObject *inst, PyObject *cls) +object_isinstance(PyObject *inst, PyObject *cls) { PyObject *icls; int retval; @@ -2461,21 +2461,23 @@ recursive_isinstance(PyObject *inst, PyObject *cls) } static int -object_isinstance(PyThreadState *tstate, PyObject *inst, PyObject *cls) +object_recursive_isinstance(PyThreadState *tstate, PyObject *inst, PyObject *cls) { _Py_IDENTIFIER(__instancecheck__); - PyObject *checker; /* Quick test for an exact match */ - if (Py_TYPE(inst) == (PyTypeObject *)cls) + if (Py_TYPE(inst) == (PyTypeObject *)cls) { return 1; + } /* We know what type's __instancecheck__ does. */ if (PyType_CheckExact(cls)) { - return recursive_isinstance(inst, cls); + return object_isinstance(inst, cls); } if (PyTuple_Check(cls)) { + /* Not a general sequence -- that opens up the road to + recursion and stack overflow. */ if (_Py_EnterRecursiveCall(tstate, " in __instancecheck__")) { return -1; } @@ -2483,37 +2485,41 @@ object_isinstance(PyThreadState *tstate, PyObject *inst, PyObject *cls) int r = 0; for (Py_ssize_t i = 0; i < n; ++i) { PyObject *item = PyTuple_GET_ITEM(cls, i); - r = object_isinstance(tstate, inst, item); - if (r != 0) + r = object_recursive_isinstance(tstate, inst, item); + if (r != 0) { /* either found it, or got an error */ break; + } } _Py_LeaveRecursiveCall(tstate); return r; } - checker = _PyObject_LookupSpecial(cls, &PyId___instancecheck__); + PyObject *checker = _PyObject_LookupSpecial(cls, &PyId___instancecheck__); if (checker != NULL) { - int ok = -1; if (_Py_EnterRecursiveCall(tstate, " in __instancecheck__")) { Py_DECREF(checker); - return ok; + return -1; } + PyObject *res = _PyObject_CallOneArg(checker, inst); _Py_LeaveRecursiveCall(tstate); Py_DECREF(checker); - if (res != NULL) { - ok = PyObject_IsTrue(res); - Py_DECREF(res); + + if (res == NULL) { + return -1; } + int ok = PyObject_IsTrue(res); + Py_DECREF(res); + return ok; } else if (_PyErr_Occurred(tstate)) { return -1; } - /* Probably never reached anymore. */ - return recursive_isinstance(inst, cls); + /* cls has no __instancecheck__() method */ + return object_isinstance(inst, cls); } @@ -2521,7 +2527,7 @@ int PyObject_IsInstance(PyObject *inst, PyObject *cls) { PyThreadState *tstate = _PyThreadState_GET(); - return object_isinstance(tstate, inst, cls); + return object_recursive_isinstance(tstate, inst, cls); } @@ -2611,7 +2617,7 @@ PyObject_IsSubclass(PyObject *derived, PyObject *cls) int _PyObject_RealIsInstance(PyObject *inst, PyObject *cls) { - return recursive_isinstance(inst, cls); + return object_isinstance(inst, cls); } int |