diff options
| -rw-r--r-- | Lib/test/test_descr.py | 36 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Core and Builtins/2020-07-18-08-15-32.bpo-41295.pu8Ezo.rst | 3 | ||||
| -rw-r--r-- | Objects/typeobject.c | 27 |
3 files changed, 59 insertions, 7 deletions
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py index c4d900a..18397a8 100644 --- a/Lib/test/test_descr.py +++ b/Lib/test/test_descr.py @@ -4315,6 +4315,42 @@ order (MRO) for bases """ else: self.fail("Carlo Verre __delattr__ succeeded!") + def test_carloverre_multi_inherit_valid(self): + class A(type): + def __setattr__(cls, key, value): + type.__setattr__(cls, key, value) + + class B: + pass + + class C(B, A): + pass + + obj = C('D', (object,), {}) + try: + obj.test = True + except TypeError: + self.fail("setattr through direct base types should be legal") + + def test_carloverre_multi_inherit_invalid(self): + class A(type): + def __setattr__(cls, key, value): + object.__setattr__(cls, key, value) # this should fail! + + class B: + pass + + class C(B, A): + pass + + obj = C('D', (object,), {}) + try: + obj.test = True + except TypeError: + pass + else: + self.fail("setattr through indirect base types should be rejected") + def test_weakref_segfault(self): # Testing weakref segfault... # SF 742911 diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-07-18-08-15-32.bpo-41295.pu8Ezo.rst b/Misc/NEWS.d/next/Core and Builtins/2020-07-18-08-15-32.bpo-41295.pu8Ezo.rst new file mode 100644 index 0000000..d61fd8f --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2020-07-18-08-15-32.bpo-41295.pu8Ezo.rst @@ -0,0 +1,3 @@ +Resolve a regression in CPython 3.8.4 where defining "__setattr__" in a +multi-inheritance setup and calling up the hierarchy chain could fail +if builtins/extension types were involved in the base types. diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 0012869..0acde71 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -5822,14 +5822,29 @@ hackcheck(PyObject *self, setattrofunc func, const char *what) return 1; } assert(PyTuple_Check(mro)); - Py_ssize_t i, n; - n = PyTuple_GET_SIZE(mro); - for (i = 0; i < n; i++) { + + /* Find the (base) type that defined the type's slot function. */ + PyTypeObject *defining_type = type; + Py_ssize_t i; + for (i = PyTuple_GET_SIZE(mro) - 1; i >= 0; i--) { PyTypeObject *base = (PyTypeObject*) PyTuple_GET_ITEM(mro, i); + if (base->tp_setattro == slot_tp_setattro) { + /* Ignore Python classes: + they never define their own C-level setattro. */ + } + else if (base->tp_setattro == type->tp_setattro) { + defining_type = base; + break; + } + } + + /* Reject calls that jump over intermediate C-level overrides. */ + for (PyTypeObject *base = defining_type; base; base = base->tp_base) { if (base->tp_setattro == func) { - /* 'func' is the earliest non-Python implementation in the MRO. */ + /* 'func' is the right slot function to call. */ break; - } else if (base->tp_setattro != slot_tp_setattro) { + } + else if (base->tp_setattro != slot_tp_setattro) { /* 'base' is not a Python class and overrides 'func'. Its tp_setattro should be called instead. */ PyErr_Format(PyExc_TypeError, @@ -5839,8 +5854,6 @@ hackcheck(PyObject *self, setattrofunc func, const char *what) return 0; } } - /* Either 'func' is not in the mro (which should fail when checking 'self'), - or it's the right slot function to call. */ return 1; } |