GH-89519: Deprecate classmethod descriptor chaining (#92379)

Summary: backporting upstream commit `ebaf0945f9f` (merged upstream [PR GH-92379](python/cpython#92379)), part of upstream issue [GH-89519](python/cpython#89519)

Reviewed By: swtaarrs

Differential Revision: D50534764

fbshipit-source-id: e74c8910e56f117b3c1cab3442de7394b0bd8b22

Author: itamaro

Doc/howto/descriptor.rst

@@ -1349,6 +1349,8 @@ Using the non-data descriptor protocol, a pure Python version of
             if cls is None:
                 cls = type(obj)
             if hasattr(type(self.f), '__get__'):
+                # This code path was added in Python 3.9
+                # and was deprecated in Python 3.11.
                 return self.f.__get__(cls, cls)
             return MethodType(self.f, cls)
 
@@ -1386,7 +1388,7 @@ Using the non-data descriptor protocol, a pure Python version of
 The code path for ``hasattr(type(self.f), '__get__')`` was added in
 Python 3.9 and makes it possible for :func:`classmethod` to support
 chained decorators.  For example, a classmethod and property could be
-chained together:
+chained together.  In Python 3.11, this functionality was deprecated.
 
 .. testcode::
 

Doc/library/functions.rst

@@ -271,6 +271,11 @@ are always available.  They are listed here in alphabetical order.
       ``__name__``, ``__qualname__``, ``__doc__`` and ``__annotations__``) and
       have a new ``__wrapped__`` attribute.
 
+   .. versionchanged:: 3.11
+      Class methods can no longer wrap other :term:`descriptors <descriptor>` such as
+      :func:`property`.
+
+
 .. function:: compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)
 
    Compile the *source* into a code or AST object.  Code objects can be executed

Misc/NEWS.d/next/Core and Builtins/2022-05-06-02-29-53.gh-issue-89519.4OfkRE.rst

@@ -0,0 +1,4 @@
+Chaining classmethod descriptors (introduced in bpo-19072) is deprecated. It
+can no longer be used to wrap other descriptors such as property().  The
+core design of this feature was flawed, and it caused a number of downstream
+problems.