[Python-checkins] bpo-41910: specify the default implementations of object.__eq__ and object.__ne__ (GH-22874)

[miss-islington]

https://github.com/python/cpython/commit/3c69f0c933d4790855929f1fcd74e4a0fefb5d52
commit: 3c69f0c933d4790855929f1fcd74e4a0fefb5d52
branch: master
author: Brett Cannon <brett at python.org>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2020-10-21T16:24:38-07:00
summary:

bpo-41910: specify the default implementations of object.__eq__ and object.__ne__ (GH-22874)



See Objects/typeobject.c:object_richcompare() for the implementation of this in CPython.

Automerge-Triggered-By: GH:brettcannon

files:
A Misc/NEWS.d/next/Core and Builtins/2020-10-21-14-40-54.bpo-41910.CzBMit.rst
M Doc/reference/datamodel.rst

diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index ab4eb478efb8b..d92e19761a965 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -1395,12 +1395,14 @@ Basic customization
    context (e.g., in the condition of an ``if`` statement), Python will call
    :func:`bool` on the value to determine if the result is true or false.
 
-   By default, :meth:`__ne__` delegates to :meth:`__eq__` and
-   inverts the result unless it is ``NotImplemented``.  There are no other
-   implied relationships among the comparison operators, for example,
-   the truth of ``(x<y or x==y)`` does not imply ``x<=y``.
-   To automatically generate ordering operations from a single root operation,
-   see :func:`functools.total_ordering`.
+   By default, ``object`` implements :meth:`__eq__` by using ``is``, returning
+   ``NotImplemented`` in the case of a false comparison:
+   ``True if x is y else NotImplemented``. For :meth:`__ne__`, by default it
+   delegates to :meth:`__eq__` and inverts the result unless it is
+   ``NotImplemented``.  There are no other implied relationships among the
+   comparison operators or default implementations; for example, the truth of
+   ``(x<y or x==y)`` does not imply ``x<=y``. To automatically generate ordering
+   operations from a single root operation, see :func:`functools.total_ordering`.
 
    See the paragraph on :meth:`__hash__` for
    some important notes on creating :term:`hashable` objects which support
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-10-21-14-40-54.bpo-41910.CzBMit.rst b/Misc/NEWS.d/next/Core and Builtins/2020-10-21-14-40-54.bpo-41910.CzBMit.rst
new file mode 100644
index 0000000000000..a40e2519a62c6
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-10-21-14-40-54.bpo-41910.CzBMit.rst	
@@ -0,0 +1 @@
+Document the default implementation of `object.__eq__`.