bpo-40170: Convert PyDescr_IsData() to static inline function (GH-24535)

Doc/c-api/descriptor.rst

@@ -32,8 +32,8 @@ found in the dictionary of type objects.
 
 .. c:function:: int PyDescr_IsData(PyObject *descr)
 
-   Return true if the descriptor objects *descr* describes a data attribute, or
-   false if it describes a method.  *descr* must be a descriptor object; there is
+   Return non-zero if the descriptor objects *descr* describes a data attribute, or
+   ``0`` if it describes a method.  *descr* must be a descriptor object; there is
    no error checking.
 
 

Include/descrobject.h

@@ -93,7 +93,7 @@ PyAPI_FUNC(PyObject *) PyDescr_NewGetSet(PyTypeObject *,
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(PyObject *) PyDescr_NewWrapper(PyTypeObject *,
                                                 struct wrapperbase *, void *);
-#define PyDescr_IsData(d) (Py_TYPE(d)->tp_descr_set != NULL)
+PyAPI_FUNC(int) PyDescr_IsData(PyObject *);
 #endif
 
 PyAPI_FUNC(PyObject *) PyDictProxy_New(PyObject *);

Misc/NEWS.d/next/Core and Builtins/2021-02-15-13-41-14.bpo-40170.r2FAtl.rst

@@ -0,0 +1,3 @@
+Convert :c:func:`PyDescr_IsData` macro to a function to hide implementation
+details: The macro accessed :c:member:`PyTypeObject.tp_descr_set` directly.
+Patch by Erlend E. Aasland.

Objects/descrobject.c

@@ -995,6 +995,11 @@ PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *base, void *wrapped)
     return (PyObject *)descr;
 }
 
+int
+PyDescr_IsData(PyObject *ob)
+{
+    return Py_TYPE(ob)->tp_descr_set != NULL;
+}
 
 /* --- mappingproxy: read-only proxy for mappings --- */