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Code Issues Releases Wiki Activity

completely ignore old-style stuff for type checking overloading

This commit is contained in:
Benjamin Peterson 2009-05-16 22:40:56 +00:00
parent 94eaba78b7
commit a27dbc68f0
2 changed files with 42 additions and 61 deletions
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21
Lib/test/test_typechecks.py
View File

@ -29,10 +29,6 @@ class SubInt(Integer):
pass
class Evil:
def __instancecheck__(self, inst): return False
class TypeChecksTest(unittest.TestCase):
def testIsSubclassInternal(self):
@ -75,11 +71,18 @@ class TypeChecksTest(unittest.TestCase):
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():

82
Objects/abstract.c
View File

@ -2902,7 +2902,6 @@ int
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 @@ PyObject_IsInstance(PyObject *inst, PyObject *cls)
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 @@ int
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 @@ PyObject_IsSubclass(PyObject *derived, PyObject *cls)
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);
}