[Python-3000-checkins] r67248 - in python/branches/py3k: Lib/test/test_descr.py Objects/typeobject.c

[benjamin.peterson]

Author: benjamin.peterson
Date: Mon Nov 17 23:45:50 2008
New Revision: 67248

Log:
Merged revisions 67246 via svnmerge from
svn+ssh://pythondev at svn.python.org/python/trunk

........
r67246 | benjamin.peterson | 2008-11-17 16:39:09 -0600 (Mon, 17 Nov 2008) | 5 lines

when __getattr__ is a descriptor, call it correctly; fixes #4230

patch from Ziga Seilnacht
........


Modified:
python/branches/py3k/ (props changed)
python/branches/py3k/Lib/test/test_descr.py
python/branches/py3k/Objects/typeobject.c

Modified: python/branches/py3k/Lib/test/test_descr.py
==============================================================================
--- python/branches/py3k/Lib/test/test_descr.py (original)
+++ python/branches/py3k/Lib/test/test_descr.py Mon Nov 17 23:45:50 2008
@@ -4001,6 +4001,46 @@
c[1:2] = 3
self.assertEqual(c.value, 3)

+ def test_getattr_hooks(self):
+ # issue 4230
+
+ class Descriptor(object):
+ counter = 0
+ def __get__(self, obj, objtype=None):
+ def getter(name):
+ self.counter += 1
+ raise AttributeError(name)
+ return getter
+
+ descr = Descriptor()
+ class A(object):
+ __getattribute__ = descr
+ class B(object):
+ __getattr__ = descr
+ class C(object):
+ __getattribute__ = descr
+ __getattr__ = descr
+
+ self.assertRaises(AttributeError, getattr, A(), "attr")
+ self.assertEquals(descr.counter, 1)
+ self.assertRaises(AttributeError, getattr, B(), "attr")
+ self.assertEquals(descr.counter, 2)
+ self.assertRaises(AttributeError, getattr, C(), "attr")
+ self.assertEquals(descr.counter, 4)
+
+ import gc
+ class EvilGetattribute(object):
+ # This used to segfault
+ def __getattr__(self, name):
+ raise AttributeError(name)
+ def __getattribute__(self, name):
+ del EvilGetattribute.__getattr__
+ for i in range(5):
+ gc.collect()
+ raise AttributeError(name)
+
+ self.assertRaises(AttributeError, getattr, EvilGetattribute(), "attr")
+

class DictProxyTests(unittest.TestCase):
def setUp(self):

Modified: python/branches/py3k/Objects/typeobject.c
==============================================================================
--- python/branches/py3k/Objects/typeobject.c (original)
+++ python/branches/py3k/Objects/typeobject.c Mon Nov 17 23:45:50 2008
@@ -4960,6 +4960,24 @@
}

static PyObject *
+call_attribute(PyObject *self, PyObject *attr, PyObject *name)
+{
+ PyObject *res, *descr = NULL;
+ descrgetfunc f = Py_TYPE(attr)->tp_descr_get;
+
+ if (f != NULL) {
+ descr = f(attr, self, (PyObject *)(Py_TYPE(self)));
+ if (descr == NULL)
+ return NULL;
+ else
+ attr = descr;
+ }
+ res = PyObject_CallFunctionObjArgs(attr, name, NULL);
+ Py_XDECREF(descr);
+ return res;
+}
+
+static PyObject *
slot_tp_getattr_hook(PyObject *self, PyObject *name)
{
PyTypeObject *tp = Py_TYPE(self);
@@ -4978,24 +4996,39 @@
if (getattribute_str == NULL)
return NULL;
}
+ /* speed hack: we could use lookup_maybe, but that would resolve the
+ method fully for each attribute lookup for classes with
+ __getattr__, even when the attribute is present. So we use
+ _PyType_Lookup and create the method only when needed, with
+ call_attribute. */
getattr = _PyType_Lookup(tp, getattr_str);
if (getattr == NULL) {
/* No __getattr__ hook: use a simpler dispatcher */
tp->tp_getattro = slot_tp_getattro;
return slot_tp_getattro(self, name);
}
+ Py_INCREF(getattr);
+ /* speed hack: we could use lookup_maybe, but that would resolve the
+ method fully for each attribute lookup for classes with
+ __getattr__, even when self has the default __getattribute__
+ method. So we use _PyType_Lookup and create the method only when
+ needed, with call_attribute. */
getattribute = _PyType_Lookup(tp, getattribute_str);
if (getattribute == NULL ||
(Py_TYPE(getattribute) == &PyWrapperDescr_Type &&
((PyWrapperDescrObject *)getattribute)->d_wrapped ==
(void *)PyObject_GenericGetAttr))
res = PyObject_GenericGetAttr(self, name);
- else
- res = PyObject_CallFunctionObjArgs(getattribute, self, name, NULL);
+ else {
+ Py_INCREF(getattribute);
+ res = call_attribute(self, getattribute, name);
+ Py_DECREF(getattribute);
+ }
if (res == NULL && PyErr_ExceptionMatches(PyExc_AttributeError)) {
PyErr_Clear();
- res = PyObject_CallFunctionObjArgs(getattr, self, name, NULL);
+ res = call_attribute(self, getattr, name);
}
+ Py_DECREF(getattr);
return res;
}