- 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.

1 files changed, 30 insertions, 28 deletions

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 @@ static PyMemberDef instancemethod_memberlist[] = {
 	{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 @@ instancemethod_getattro(PyObject *obj, PyObject *name)
 		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 @@ PyTypeObject PyMethod_Type = {
 	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 */