Fix error checking done by abstract_issubclass and abstract_isinstance.
isinstance() now allows any object as the first argument and a class, a
type or something with a __bases__ tuple attribute for the second
argument. This closes SF patch #464992.
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 33991a8..24b09f5 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -1740,45 +1740,46 @@
/* isinstance(), issubclass() */
-static int
-abstract_issubclass(PyObject *derived, PyObject *cls, int first)
+static PyObject *
+abstract_get_bases(PyObject *cls)
{
static PyObject *__bases__ = NULL;
PyObject *bases;
- int i, n;
- int r = 0;
if (__bases__ == NULL) {
__bases__ = PyString_FromString("__bases__");
if (__bases__ == NULL)
- return -1;
+ return NULL;
}
- if (first) {
- bases = PyObject_GetAttr(cls, __bases__);
- if (bases == NULL || !PyTuple_Check(bases)) {
- Py_XDECREF(bases);
- PyErr_SetString(PyExc_TypeError,
- "issubclass() arg 2 must be a class");
- return -1;
- }
- Py_DECREF(bases);
+ bases = PyObject_GetAttr(cls, __bases__);
+ if (bases == NULL || !PyTuple_Check(bases)) {
+ Py_XDECREF(bases);
+ return NULL;
}
+ return bases;
+}
+
+
+static int
+abstract_issubclass(PyObject *derived, PyObject *cls)
+{
+ PyObject *bases;
+ int i, n;
+ int r = 0;
+
+
if (derived == cls)
return 1;
- bases = PyObject_GetAttr(derived, __bases__);
- if (bases == NULL || !PyTuple_Check(bases)) {
- Py_XDECREF(bases);
- PyErr_SetString(PyExc_TypeError,
- "issubclass() arg 1 must be a class");
- return -1;
- }
+ bases = abstract_get_bases(derived);
+ if (bases == NULL)
+ return 0;
n = PyTuple_GET_SIZE(bases);
for (i = 0; i < n; i++) {
- r = abstract_issubclass(PyTuple_GET_ITEM(bases, i), cls, 0);
+ r = abstract_issubclass(PyTuple_GET_ITEM(bases, i), cls);
if (r != 0)
break;
}
@@ -1795,12 +1796,10 @@
static PyObject *__class__ = NULL;
int retval = 0;
- if (PyClass_Check(cls)) {
- if (PyInstance_Check(inst)) {
- PyObject *inclass =
- (PyObject*)((PyInstanceObject*)inst)->in_class;
- retval = PyClass_IsSubclass(inclass, cls);
- }
+ if (PyClass_Check(cls) && PyInstance_Check(inst)) {
+ PyObject *inclass =
+ (PyObject*)((PyInstanceObject*)inst)->in_class;
+ retval = PyClass_IsSubclass(inclass, cls);
}
else if (PyType_Check(cls)) {
retval = PyObject_TypeCheck(inst, (PyTypeObject *)cls);
@@ -1819,31 +1818,30 @@
}
return retval;
}
- else if (!PyInstance_Check(inst)) {
+ else {
+ PyObject *cls_bases = abstract_get_bases(cls);
+ if (cls_bases == NULL) {
+ PyErr_SetString(PyExc_TypeError,
+ "isinstance() arg 2 must be a class or type");
+ return -1;
+ }
+ Py_DECREF(cls_bases);
if (__class__ == NULL) {
__class__ = PyString_FromString("__class__");
if (__class__ == NULL)
return -1;
}
icls = PyObject_GetAttr(inst, __class__);
- if (icls != NULL) {
- retval = abstract_issubclass(icls, cls, 1);
- Py_DECREF(icls);
- if (retval < 0 &&
- !PyErr_ExceptionMatches(PyExc_TypeError))
- return -1;
+ if (icls == NULL) {
+ PyErr_Clear();
+ retval = 0;
}
- else
- retval = -1;
+ else {
+ retval = abstract_issubclass(icls, cls);
+ Py_DECREF(icls);
+ }
}
- else
- retval = -1;
- if (retval < 0) {
- PyErr_SetString(PyExc_TypeError,
- "isinstance() arg 2 must be a class or type "
- "or tuple of those");
- }
return retval;
}
@@ -1853,7 +1851,26 @@
int retval;
if (!PyClass_Check(derived) || !PyClass_Check(cls)) {
- retval = abstract_issubclass(derived, cls, 1);
+ PyObject *derived_bases;
+ PyObject *cls_bases;
+
+ derived_bases = abstract_get_bases(derived);
+ if (derived_bases == NULL) {
+ PyErr_SetString(PyExc_TypeError,
+ "issubclass() arg 1 must be a class");
+ return -1;
+ }
+ Py_DECREF(derived_bases);
+
+ cls_bases = abstract_get_bases(cls);
+ if (cls_bases == NULL) {
+ PyErr_SetString(PyExc_TypeError,
+ "issubclass() arg 2 must be a class");
+ return -1;
+ }
+ Py_DECREF(cls_bases);
+
+ retval = abstract_issubclass(derived, cls);
}
else {
/* shortcut */