python/typing_extensions 4.12.0a1

on GitHub

This release primarily tests a revised release workflow. If all goes
well, release 4.12.0rc1 will follow soon.

• Backport the typing.NoDefault sentinel object from Python 3.13.
  TypeVars, ParamSpecs and TypeVarTuples without default values now have
  their __default__ attribute set to this sentinel value.
• TypeVars, ParamSpecs and TypeVarTuples now have a has_default()
  method, matching typing.TypeVar, typing.ParamSpec and
  typing.TypeVarTuple on Python 3.13+.
• TypeVars, ParamSpecs and TypeVarTuples with default=None passed to
  their constructors now have their __default__ attribute set to None
  at runtime rather than types.NoneType.
• Fix most tests for TypeVar, ParamSpec and TypeVarTuple on Python
  3.13.0b1 and newer.
• Backport CPython PR #118774,
  allowing type parameters without default values to follow those with
  default values in some type parameter lists. Patch by Alex Waygood,
  backporting a CPython PR by Jelle Zijlstra.
• It is now disallowed to use a TypeVar with a default value after a
  TypeVarTuple in a type parameter list. This matches the CPython
  implementation of PEP 696 on Python 3.13+.
• Fix bug in PEP-696 implementation where default values for ParamSpecs
  would be cast to tuples if a list was provided as the default value.
  Patch by Alex Waygood.
• Fix Protocol tests on Python 3.13.0a6 and newer. 3.13.0a6 adds a new
  __static_attributes__ attribute to all classes in Python,
  which broke some assumptions made by the implementation of
  typing_extensions.Protocol. Similarly, 3.13.0b1 adds the new
  __firstlineno__ attribute to all classes.
• Fix AttributeError when using typing_extensions.runtime_checkable
  in combination with typing.Protocol on Python 3.12.2 or newer.
  Patch by Alex Waygood.
• At runtime, assert_never now includes the repr of the argument
  in the AssertionError. Patch by Hashem, backporting of the original
  fix python/cpython#91720 by Jelle Zijlstra.
• The second and third parameters of typing_extensions.Generator,
  and the second parameter of typing_extensions.AsyncGenerator,
  now default to None. This matches the behaviour of typing.Generator
  and typing.AsyncGenerator on Python 3.13+.
• typing_extensions.ContextManager and
  typing_extensions.AsyncContextManager now have an optional second
  parameter, which defaults to Optional[bool]. The new parameter
  signifies the return type of the __(a)exit__ method, matching
  typing.ContextManager and typing.AsyncContextManager on Python
  3.13+.
• Backport types.CapsuleType from Python 3.13.