[Python-checkins] [3.8] [3.9] bpo-41688: Document bug in **= dispatching in the language data… (GH-22172) (GH-22175)

Tue Sep 15 09:44:32 EDT 2020

https://github.com/python/cpython/commit/4c4c354de2c9a290afbd4e5fcba07e3696ca0396
commit: 4c4c354de2c9a290afbd4e5fcba07e3696ca0396
branch: 3.8
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2020年09月09日T11:15:49-07:00
summary:
[3.8] [3.9] bpo-41688: Document bug in **= dispatching in the language data… (GH-22172) (GH-22175)
(cherry picked from commit 46bc21e1780016aaacd34e472f838dc792fb674c)
Co-authored-by: Ammar Askar <ammar at ammaraskar.com>
Automerge-Triggered-By: @brettcannon
files:
M Doc/reference/datamodel.rst

diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index c1262cdb9c106..3f05385862416 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -2404,6 +2404,13 @@ left undefined.
 :ref:`faq-augmented-assignment-tuple-error`), but this behavior is in fact
 part of the data model.
 
+ .. note::
+
+ Due to a bug in the dispatching mechanism for ``**=``, a class that
+ defines :meth:`__ipow__` but returns ``NotImplemented`` would fail to
+ fall back to ``x.__pow__(y)`` and ``y.__rpow__(x)``. This bug is fixed
+ in Python 3.10.
+
 
 .. method:: object.__neg__(self)
 object.__pos__(self)
