https://github.com/python/cpython/commit/14efcadfd4cbdab0ff204cad9d89871cc64e6cfb
commit: 14efcadfd4cbdab0ff204cad9d89871cc64e6cfb
branch: main
author: Jelle Zijlstra <jelle.zijls...@gmail.com>
committer: JelleZijlstra <jelle.zijls...@gmail.com>
date: 2025-04-16T17:44:17Z
summary:
typing docs: Clarify Protocol / runtime_checkable docs (#132606)
- Explicitly say that isinstance/issubclass do not work on non-runtime checkable
protocols.
- Move the sentence "This raises TypeError when applied to a non-protocol
class". It
took me quite some time to decide what "this" was here: it refers to applying
the
decorator, not to an isinstance() call.
Co-authored-by: Alex Waygood <alex.wayg...@gmail.com>
files:
M Doc/library/typing.rst
diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst
index 84f77e8f206438..a0beed4a8c77fb 100644
--- a/Doc/library/typing.rst
+++ b/Doc/library/typing.rst
@@ -2455,7 +2455,8 @@ types.
See :pep:`544` for more details. Protocol classes decorated with
:func:`runtime_checkable` (described later) act as simple-minded runtime
protocols that check only the presence of given attributes, ignoring their
- type signatures.
+ type signatures. Protocol classes without this decorator cannot be used
+ as the second argument to :func:`isinstance` or :func:`issubclass`.
Protocol classes can be generic, for example::
@@ -2479,8 +2480,7 @@ types.
Mark a protocol class as a runtime protocol.
Such a protocol can be used with :func:`isinstance` and :func:`issubclass`.
- This raises :exc:`TypeError` when applied to a non-protocol class. This
- allows a simple-minded structural check, very similar to "one trick ponies"
+ This allows a simple-minded structural check, very similar to "one trick
ponies"
in :mod:`collections.abc` such as :class:`~collections.abc.Iterable`. For
example::
@runtime_checkable
@@ -2496,6 +2496,8 @@ types.
import threading
assert isinstance(threading.Thread(name='Bob'), Named)
+ This decorator raises :exc:`TypeError` when applied to a non-protocol class.
+
.. note::
:func:`!runtime_checkable` will check only the presence of the required
_______________________________________________
Python-checkins mailing list -- python-checkins@python.org
To unsubscribe send an email to python-checkins-le...@python.org
https://mail.python.org/mailman3/lists/python-checkins.python.org/
Member address: arch...@mail-archive.com
