From 8cece1d0031ec4e7371a62cb4af15be55667384d Mon Sep 17 00:00:00 2001 From: johnslavik Date: Tue, 28 Jul 2026 00:48:05 +0200 Subject: [PATCH 1/2] Track deprecation related to runtime-checkable protocols until 3.20 --- Doc/deprecations/pending-removal-in-3.20.rst | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/Doc/deprecations/pending-removal-in-3.20.rst b/Doc/deprecations/pending-removal-in-3.20.rst index 011565dfbb090d..d771764502c910 100644 --- a/Doc/deprecations/pending-removal-in-3.20.rst +++ b/Doc/deprecations/pending-removal-in-3.20.rst @@ -53,3 +53,12 @@ Pending removal in Python 3.20 * Creating instances of abstract AST nodes (such as :class:`ast.AST` or :class:`!ast.expr`) is deprecated and will raise an error in Python 3.20. + +* :mod:`typing`: + + * It is deprecated to call :func:`isinstance` and :func:`issubclass` checks on + protocol classes that were not explicitly decorated with :func:`!runtime_checkable` + but that inherit from a runtime-checkable protocol class. + This will raise a :exc:`TypeError` in Python 3.20. + + (Contributed by Bartosz Sławecki in :gh:`132604`.) From e32c606f9330c875f2a621d2bfa8591ae242161f Mon Sep 17 00:00:00 2001 From: johnslavik Date: Tue, 28 Jul 2026 11:04:56 +0200 Subject: [PATCH 2/2] Add deprecation note to 3.15 what's new --- Doc/whatsnew/3.15.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Doc/whatsnew/3.15.rst b/Doc/whatsnew/3.15.rst index 250558dd1341a4..daac31fd7f4b17 100644 --- a/Doc/whatsnew/3.15.rst +++ b/Doc/whatsnew/3.15.rst @@ -2317,6 +2317,13 @@ New deprecations :func:`issubclass`, but warnings were not previously emitted if it was merely imported or accessed from the :mod:`!typing` module. + * It is deprecated to call :func:`isinstance` and :func:`issubclass` checks on + protocol classes that were not explicitly decorated with :func:`!runtime_checkable` + but that inherit from a runtime-checkable protocol class. + This will raise a :exc:`TypeError` in Python 3.20. + + (Contributed by Bartosz Sławecki in :gh:`132604`.) + * :mod:`webbrowser`: