Ensure super() lookup of descriptor from classmethod works (SF #743627)

Lib/test/test_descr.py

@@ -2064,6 +2064,20 @@ def supers():
     vereq(dd.x, "hello")
     vereq(super(DDsub, dd).x, 42)
 
+    # Ensure that super() lookup of descriptor from classmethod
+    # works (SF ID# 743627)
+
+    class Base(object):
+        aProp = property(lambda self: "foo")
+
+    class Sub(Base):
+        def test(klass):
+            return super(Sub,klass).aProp
+        test = classmethod(test)
+
+    veris(Sub.test(), Base.aProp)
+
+
 def inherits():
     if verbose: print "Testing inheritance from basic types..."
 

Objects/typeobject.c

@@ -5537,7 +5537,14 @@ super_getattro(PyObject *self, PyObject *name)
 				Py_INCREF(res);
 				f = res->ob_type->tp_descr_get;
 				if (f != NULL) {
-					tmp = f(res, su->obj,
+					tmp = f(res,
+						/* Only pass 'obj' param if
+						   this is instance-mode super 
+						   (See SF ID #743627)
+						*/
+						(su->obj==su->obj_type 
+							? (PyObject *)NULL 
+							: su->obj),
 						(PyObject *)starttype);
 					Py_DECREF(res);
 					res = tmp;