SF bug 542984.
Change type_get_doc (the get function for __doc__) to look in tp_dict
more often, and if it finds a descriptor in tp_dict, to call it (with
a NULL instance). This means you can add a __doc__ descriptor to a
new-style class that returns instance docs when called on an instance,
and class docs when called on a class -- or the same docs in either
case, but lazily computed.
I'll also check this into the 2.2 maintenance branch.
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index deb7320..f647d57 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -82,15 +82,19 @@
type_get_doc(PyTypeObject *type, void *context)
{
PyObject *result;
- if (!(type->tp_flags & Py_TPFLAGS_HEAPTYPE)) {
- if (type->tp_doc == NULL) {
- Py_INCREF(Py_None);
- return Py_None;
- }
+ if (!(type->tp_flags & Py_TPFLAGS_HEAPTYPE) && type->tp_doc != NULL)
return PyString_FromString(type->tp_doc);
- }
result = PyDict_GetItemString(type->tp_dict, "__doc__");
- Py_INCREF(result);
+ if (result == NULL) {
+ result = Py_None;
+ Py_INCREF(result);
+ }
+ else if (result->ob_type->tp_descr_get) {
+ result = result->ob_type->tp_descr_get(result, NULL, type);
+ }
+ else {
+ Py_INCREF(result);
+ }
return result;
}