- When method objects have an attribute that can be satisfied either
by the function object or by the method object, the function
object's attribute usually wins. Christian Tismer pointed out that
that this is really a mistake, because this only happens for special
methods (like __reduce__) where the method object's version is
really more appropriate than the function's attribute. So from now
on, all method attributes will have precedence over function
attributes with the same name.
diff --git a/Misc/NEWS b/Misc/NEWS
index 30fe4be..f7b1e96 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,15 @@
Core and builtins
-----------------
+- When method objects have an attribute that can be satisfied either
+ by the function object or by the method object, the function
+ object's attribute usually wins. Christian Tismer pointed out that
+ that this is really a mistake, because this only happens for special
+ methods (like __reduce__) where the method object's version is
+ really more appropriate than the function's attribute. So from now
+ on, all method attributes will have precedence over function
+ attributes with the same name.
+
- Critical bugfix, for SF bug 839548: if a weakref with a callback,
its callback, and its weakly referenced object, all became part of
cyclic garbage during a single run of garbage collection, the order
diff --git a/Objects/classobject.c b/Objects/classobject.c
index 84b297c..17a5646 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -2138,19 +2138,34 @@
{NULL} /* Sentinel */
};
-/* The getattr() implementation for PyMethod objects is similar to
- PyObject_GenericGetAttr(), but instead of looking in __dict__ it
- asks im_self for the attribute. Then the error handling is a bit
- different because we want to preserve the exception raised by the
- delegate, unless we have an alternative from our class. */
+/* Christian Tismer argued convincingly that method attributes should
+ (nearly) always override function attributes.
+ The one exception is __doc__; there's a default __doc__ which
+ should only be used for the class, not for instances */
+
+static PyObject *
+instancemethod_get_doc(PyMethodObject *im, void *context)
+{
+ static PyObject *docstr;
+ if (docstr == NULL) {
+ docstr= PyString_InternFromString("__doc__");
+ if (docstr == NULL)
+ return NULL;
+ }
+ return PyObject_GetAttr(im->im_func, docstr);
+}
+
+static PyGetSetDef instancemethod_getset[] = {
+ {"__doc__", (getter)instancemethod_get_doc, NULL, NULL},
+ {0}
+};
static PyObject *
instancemethod_getattro(PyObject *obj, PyObject *name)
{
PyMethodObject *im = (PyMethodObject *)obj;
PyTypeObject *tp = obj->ob_type;
- PyObject *descr = NULL, *res;
- descrgetfunc f = NULL;
+ PyObject *descr = NULL;
if (PyType_HasFeature(tp, Py_TPFLAGS_HAVE_CLASS)) {
if (tp->tp_dict == NULL) {
@@ -2160,30 +2175,17 @@
descr = _PyType_Lookup(tp, name);
}
- f = NULL;
if (descr != NULL) {
- f = TP_DESCR_GET(descr->ob_type);
- if (f != NULL && PyDescr_IsData(descr))
+ descrgetfunc f = TP_DESCR_GET(descr->ob_type);
+ if (f != NULL)
return f(descr, obj, (PyObject *)obj->ob_type);
+ else {
+ Py_INCREF(descr);
+ return descr;
+ }
}
- res = PyObject_GetAttr(im->im_func, name);
- if (res != NULL || !PyErr_ExceptionMatches(PyExc_AttributeError))
- return res;
-
- if (f != NULL) {
- PyErr_Clear();
- return f(descr, obj, (PyObject *)obj->ob_type);
- }
-
- if (descr != NULL) {
- PyErr_Clear();
- Py_INCREF(descr);
- return descr;
- }
-
- assert(PyErr_Occurred());
- return NULL;
+ return PyObject_GetAttr(im->im_func, name);
}
PyDoc_STRVAR(instancemethod_doc,
@@ -2490,7 +2492,7 @@
0, /* tp_iternext */
0, /* tp_methods */
instancemethod_memberlist, /* tp_members */
- 0, /* tp_getset */
+ instancemethod_getset, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
instancemethod_descr_get, /* tp_descr_get */