[Python-checkins] bpo-32999: Fix ABC.__subclasscheck__ crash (GH-6002)
INADA Naoki
webhook-mailer at python.org
Wed Mar 7 02:27:07 EST 2018
https://github.com/python/cpython/commit/fc7df0e664198cb05cafd972f190a18ca422989c
commit: fc7df0e664198cb05cafd972f190a18ca422989c
branch: master
author: INADA Naoki <methane at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2018-03-07T16:27:01+09:00
summary:
bpo-32999: Fix ABC.__subclasscheck__ crash (GH-6002)
files:
A Misc/NEWS.d/next/Library/2018-03-06-20-30-20.bpo-32999.lgFXWl.rst
M Lib/test/test_abc.py
M Modules/_abc.c
diff --git a/Lib/test/test_abc.py b/Lib/test/test_abc.py
index af26c1d6b8c5..6fc3c95e4a64 100644
--- a/Lib/test/test_abc.py
+++ b/Lib/test/test_abc.py
@@ -392,6 +392,24 @@ class MyInt(int):
self.assertIsInstance(42, A)
self.assertIsInstance(42, (A,))
+ def test_issubclass_bad_arguments(self):
+ class A(metaclass=abc_ABCMeta):
+ pass
+
+ with self.assertRaises(TypeError):
+ issubclass({}, A) # unhashable
+
+ with self.assertRaises(TypeError):
+ issubclass(42, A) # No __mro__
+
+ # Python version supports any iterable as __mro__.
+ # But it's implementation detail and don't emulate it in C version.
+ class C:
+ __mro__ = 42 # __mro__ is not tuple
+
+ with self.assertRaises(TypeError):
+ issubclass(C(), A)
+
def test_all_new_methods_are_called(self):
class A(metaclass=abc_ABCMeta):
pass
diff --git a/Misc/NEWS.d/next/Library/2018-03-06-20-30-20.bpo-32999.lgFXWl.rst b/Misc/NEWS.d/next/Library/2018-03-06-20-30-20.bpo-32999.lgFXWl.rst
new file mode 100644
index 000000000000..45e75f939310
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-03-06-20-30-20.bpo-32999.lgFXWl.rst
@@ -0,0 +1,2 @@
+Fix C implemetation of ``ABC.__subclasscheck__(cls, subclass)`` crashed when
+``subclass`` is not a type object.
diff --git a/Modules/_abc.c b/Modules/_abc.c
index 504e23d9a74d..862883987fb7 100644
--- a/Modules/_abc.c
+++ b/Modules/_abc.c
@@ -16,6 +16,7 @@ _Py_IDENTIFIER(__abstractmethods__);
_Py_IDENTIFIER(__class__);
_Py_IDENTIFIER(__dict__);
_Py_IDENTIFIER(__bases__);
+_Py_IDENTIFIER(__mro__);
_Py_IDENTIFIER(_abc_impl);
_Py_IDENTIFIER(__subclasscheck__);
_Py_IDENTIFIER(__subclasshook__);
@@ -568,7 +569,7 @@ _abc__abc_subclasscheck_impl(PyObject *module, PyObject *self,
PyObject *subclass)
/*[clinic end generated code: output=b56c9e4a530e3894 input=1d947243409d10b8]*/
{
- PyObject *ok, *mro, *subclasses = NULL, *result = NULL;
+ PyObject *ok, *mro = NULL, *subclasses = NULL, *result = NULL;
Py_ssize_t pos;
int incache;
_abc_data *impl = _get_impl(self);
@@ -637,20 +638,31 @@ _abc__abc_subclasscheck_impl(PyObject *module, PyObject *self,
}
Py_DECREF(ok);
- /* 4. Check if it's a direct subclass. */
- mro = ((PyTypeObject *)subclass)->tp_mro;
- assert(PyTuple_Check(mro));
- for (pos = 0; pos < PyTuple_GET_SIZE(mro); pos++) {
- PyObject *mro_item = PyTuple_GET_ITEM(mro, pos);
- if (mro_item == NULL) {
+ /* 4. Check if it's a direct subclass.
+ *
+ * if cls in getattr(subclass, '__mro__', ()):
+ * cls._abc_cache.add(subclass)
+ * return True
+ */
+ if (_PyObject_LookupAttrId(subclass, &PyId___mro__, &mro) < 0) {
+ goto end;
+ }
+ if (mro != NULL) {
+ if (!PyTuple_Check(mro)) {
+ // Python version supports non-tuple iterable. Keep it as
+ // implementation detail.
+ PyErr_SetString(PyExc_TypeError, "__mro__ is not a tuple");
goto end;
}
- if ((PyObject *)self == mro_item) {
- if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) {
+ for (pos = 0; pos < PyTuple_GET_SIZE(mro); pos++) {
+ PyObject *mro_item = PyTuple_GET_ITEM(mro, pos);
+ if ((PyObject *)self == mro_item) {
+ if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) {
+ goto end;
+ }
+ result = Py_True;
goto end;
}
- result = Py_True;
- goto end;
}
}
@@ -690,7 +702,8 @@ _abc__abc_subclasscheck_impl(PyObject *module, PyObject *self,
result = Py_False;
end:
- Py_XDECREF(impl);
+ Py_DECREF(impl);
+ Py_XDECREF(mro);
Py_XDECREF(subclasses);
Py_XINCREF(result);
return result;
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