completely ignore old-style stuff for type checking overloading
diff --git a/Lib/test/test_typechecks.py b/Lib/test/test_typechecks.py
index 32aa660..64c4174 100644
--- a/Lib/test/test_typechecks.py
+++ b/Lib/test/test_typechecks.py
@@ -29,10 +29,6 @@
pass
-class Evil:
- def __instancecheck__(self, inst): return False
-
-
class TypeChecksTest(unittest.TestCase):
def testIsSubclassInternal(self):
@@ -75,11 +71,18 @@
self.assertEqual(isinstance(42, SubInt), False)
self.assertEqual(isinstance(42, (SubInt,)), False)
- def testInfiniteRecursionCaughtProperly(self):
- e = Evil()
- # This invokes isinstance() recursively, until the stack is exhausted.
- self.assertRaises(RuntimeError, isinstance, e, Evil)
- # XXX How to check the same situation for issubclass()?
+ def test_oldstyle(self):
+ # These should just be ignored.
+ class X:
+ def __instancecheck__(self, inst):
+ return True
+ def __subclasscheck__(self, cls):
+ return True
+ class Sub(X): pass
+ self.assertFalse(isinstance(3, X))
+ self.assertTrue(isinstance(X(), X))
+ self.assertFalse(issubclass(int, X))
+ self.assertTrue(issubclass(Sub, X))
def test_main():
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 2266fa1..63b2041 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2902,7 +2902,6 @@
PyObject_IsInstance(PyObject *inst, PyObject *cls)
{
static PyObject *name = NULL;
- PyObject *checker;
/* Quick test for an exact match */
if (Py_TYPE(inst) == (PyTypeObject *)cls)
@@ -2927,33 +2926,25 @@
return r;
}
- if (PyClass_Check(cls) || PyInstance_Check(cls)) {
- checker = PyObject_GetAttrString(cls, "__instancecheck__");
- if (checker == NULL) {
- if (PyErr_ExceptionMatches(PyExc_AttributeError))
- PyErr_Clear();
- else
- return -1;
- }
- }
- else {
+ if (!(PyClass_Check(cls) || PyInstance_Check(cls))) {
+ PyObject *checker;
checker = _PyObject_LookupSpecial(cls, "__instancecheck__", &name);
- }
- if (checker != NULL) {
- PyObject *res;
- int ok = -1;
- if (Py_EnterRecursiveCall(" in __instancecheck__")) {
+ if (checker != NULL) {
+ PyObject *res;
+ int ok = -1;
+ if (Py_EnterRecursiveCall(" in __instancecheck__")) {
+ Py_DECREF(checker);
+ return ok;
+ }
+ res = PyObject_CallFunctionObjArgs(checker, inst, NULL);
+ Py_LeaveRecursiveCall();
Py_DECREF(checker);
+ if (res != NULL) {
+ ok = PyObject_IsTrue(res);
+ Py_DECREF(res);
+ }
return ok;
}
- res = PyObject_CallFunctionObjArgs(checker, inst, NULL);
- Py_LeaveRecursiveCall();
- Py_DECREF(checker);
- if (res != NULL) {
- ok = PyObject_IsTrue(res);
- Py_DECREF(res);
- }
- return ok;
}
return recursive_isinstance(inst, cls);
}
@@ -2992,8 +2983,6 @@
PyObject_IsSubclass(PyObject *derived, PyObject *cls)
{
static PyObject *name = NULL;
- PyObject *t, *v, *tb;
- PyObject *checker;
if (PyTuple_Check(cls)) {
Py_ssize_t i;
@@ -3013,36 +3002,25 @@
Py_LeaveRecursiveCall();
return r;
}
- if (PyClass_Check(cls) || PyInstance_Check(cls)) {
- PyErr_Fetch(&t, &v, &tb);
- checker = PyObject_GetAttr(cls, name);
- if (checker == NULL &&
- !PyErr_ExceptionMatches(PyExc_AttributeError)) {
- Py_XDECREF(t);
- Py_XDECREF(v);
- Py_XDECREF(tb);
- return -1;
- }
- PyErr_Restore(t, v, tb);
- }
- else {
+ if (!(PyClass_Check(cls) || PyInstance_Check(cls))) {
+ PyObject *checker;
checker = _PyObject_LookupSpecial(cls, "__subclasscheck__", &name);
- }
- if (checker != NULL) {
- PyObject *res;
- int ok = -1;
- if (Py_EnterRecursiveCall(" in __subclasscheck__")) {
+ if (checker != NULL) {
+ PyObject *res;
+ int ok = -1;
+ if (Py_EnterRecursiveCall(" in __subclasscheck__")) {
+ Py_DECREF(checker);
+ return ok;
+ }
+ res = PyObject_CallFunctionObjArgs(checker, derived, NULL);
+ Py_LeaveRecursiveCall();
Py_DECREF(checker);
+ if (res != NULL) {
+ ok = PyObject_IsTrue(res);
+ Py_DECREF(res);
+ }
return ok;
}
- res = PyObject_CallFunctionObjArgs(checker, derived, NULL);
- Py_LeaveRecursiveCall();
- Py_DECREF(checker);
- if (res != NULL) {
- ok = PyObject_IsTrue(res);
- Py_DECREF(res);
- }
- return ok;
}
return recursive_issubclass(derived, cls);
}