bpo-36922: implement PEP-590 Py_TPFLAGS_METHOD_DESCRIPTOR (GH-13338)

Co-authored-by: Mark Shannon <mark@hotpy.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/Doc/c-api/typeobj.rst b/Doc/c-api/typeobj.rst
index e0ea9b9..aa66784 100644
--- a/Doc/c-api/typeobj.rst
+++ b/Doc/c-api/typeobj.rst
@@ -1045,6 +1045,32 @@ and :c:type:`PyType_Type` effectively act as defaults.)
 
       ???
 
+
+   .. data:: Py_TPFLAGS_METHOD_DESCRIPTOR
+
+      This bit indicates that objects behave like unbound methods.
+
+      If this flag is set for ``type(meth)``, then:
+
+      - ``meth.__get__(obj, cls)(*args, **kwds)`` (with ``obj`` not None)
+        must be equivalent to ``meth(obj, *args, **kwds)``.
+
+      - ``meth.__get__(None, cls)(*args, **kwds)``
+        must be equivalent to ``meth(*args, **kwds)``.
+
+      This flag enables an optimization for typical method calls like
+      ``obj.meth()``: it avoids creating a temporary "bound method" object for
+      ``obj.meth``.
+
+      .. versionadded:: 3.8
+
+      **Inheritance:**
+
+      This flag is never inherited by heap types.
+      For extension types, it is inherited whenever
+      :c:member:`~PyTypeObject.tp_descr_get` is inherited.
+
+
    .. XXX Document more flags here?