[Python-checkins] cpython: Issue 27366: PEP 487 docs updates
nick.coghlan
python-checkins at python.org
Sat Jul 30 22:43:03 EDT 2016
https://hg.python.org/cpython/rev/313e8fdb0d0c
changeset: 102498:313e8fdb0d0c
user: Nick Coghlan <ncoghlan at gmail.com>
date: Sun Jul 31 12:42:49 2016 +1000
summary:
Issue 27366: PEP 487 docs updates
- Porting note for type keyword arg handling
- __init_subclass__ note regarding metaclass hint
files:
Doc/reference/datamodel.rst | 7 +++++++
Doc/whatsnew/3.6.rst | 9 +++++++++
2 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -1672,6 +1672,13 @@
The default implementation ``object.__init_subclass__`` does
nothing, but raises an error if it is called with any arguments.
+ .. note::
+
+ The metaclass hint ``metaclass`` is consumed by the rest of the type
+ machinery, and is never passed to ``__init_subclass__`` implementations.
+ The actual metaclass (rather than the explicit hint) can be accessed as
+ ``type(cls)``.
+
.. versionadded:: 3.6
diff --git a/Doc/whatsnew/3.6.rst b/Doc/whatsnew/3.6.rst
--- a/Doc/whatsnew/3.6.rst
+++ b/Doc/whatsnew/3.6.rst
@@ -759,6 +759,15 @@
<keyword-only_parameter>`.
(Contributed by Serhiy Storchaka in :issue:`18726`.)
+* As part of :pep:`487`, the handling of keyword arguments passed to
+ :class:`type` (other than the metaclass hint, ``metaclass``) is now
+ consistently delegated to :meth:`object.__init_subclass__`. This means that
+ :meth:`type.__new__` and :meth:`type.__init__` both now accept arbitrary
+ keyword arguments, but :meth:`object.__init_subclass__` (which is called from
+ :meth:`type.__new__`) will reject them by default. Custom metaclasses
+ accepting additional keyword arguments will need to adjust their calls to
+ :meth:`type.__new__` (whether direct or via :class:`super`) accordingly.
+
Changes in the C API
--------------------
--
Repository URL: https://hg.python.org/cpython
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