https://github.com/python/cpython/commit/fbe2e0bb8a7ee75d0f9d57682436dac7d69... commit: fbe2e0bb8a7ee75d0f9d57682436dac7d69e202e branch: master author: ananthan-123 <ananthakrishnan15.2001@gmail.com> committer: GitHub <noreply@github.com> date: 2020-02-22T09:56:01-08:00 summary: bpo-17422: Language reference should specify restrictions on class namespace (#18559) The language reference now specifies restrictions on class namespaces. Adapted from a patch by Ethan Furman. files: A Misc/NEWS.d/next/Documentation/2020-02-19-11-13-47.bpo-17422.g7_9zz.rst M Doc/reference/datamodel.rst diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst index 9520f824287f6..5b3b669c5eb91 100644 --- a/Doc/reference/datamodel.rst +++ b/Doc/reference/datamodel.rst @@ -1946,10 +1946,12 @@ Once the appropriate metaclass has been identified, then the class namespace is prepared. If the metaclass has a ``__prepare__`` attribute, it is called as ``namespace = metaclass.__prepare__(name, bases, **kwds)`` (where the additional keyword arguments, if any, come from the class definition). The -``__prepare__`` method should be implemented as a :func:`classmethod`. +``__prepare__`` method should be implemented as a :func:`classmethod`. The +namespace returned by ``__prepare__`` is passed in to ``__new__``, but when +the final class object is created the namespace is copied into a new ``dict``. If the metaclass has no ``__prepare__`` attribute, then the class namespace -is initialised as an empty ordered mapping. +is initialised as an empty :func:`dict`. .. seealso:: diff --git a/Misc/NEWS.d/next/Documentation/2020-02-19-11-13-47.bpo-17422.g7_9zz.rst b/Misc/NEWS.d/next/Documentation/2020-02-19-11-13-47.bpo-17422.g7_9zz.rst new file mode 100644 index 0000000000000..f071d286176ae --- /dev/null +++ b/Misc/NEWS.d/next/Documentation/2020-02-19-11-13-47.bpo-17422.g7_9zz.rst @@ -0,0 +1 @@ +The language reference now specifies restrictions on class namespaces. Adapted from a patch by Ethan Furman.