4.12.1

• Preliminary changes for compatibility with the draft implementation
  of PEP 649 in Python 3.14. Patch by Jelle Zijlstra.
• Fix regression in v4.12.0 where nested Annotated types would cause
  TypeError to be raised if the nested Annotated type had unhashable
  metadata. Patch by Alex Waygood.

4.12.0

This release focuses on compatibility with the upcoming release of
Python 3.13. Most changes are related to the implementation of type
parameter defaults (PEP 696).

Thanks to all of the people who contributed patches, especially Alex
Waygood, who did most of the work adapting typing-extensions to the
CPython PEP 696 implementation.

There is a single change since 4.12.0rc1:

• Fix incorrect behaviour of typing_extensions.ParamSpec on Python 3.8 and
  3.9 that meant that
  isinstance(typing_extensions.ParamSpec("P"), typing.TypeVar) would have a
  different result in some situations depending on whether or not a profiling
  function had been set using sys.setprofile. Patch by Alex Waygood.

Changes included in 4.12.0rc1:

• Improve the implementation of type parameter defaults (PEP 696)
  • 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 a default value for a ParamSpec
    would be cast to a tuple if a list was provided.
    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.
• Releases are now made using Trusted Publishers
  improving the security of the release process. Patch by Jelle Zijlstra.

4.12.0rc1

This release focuses on compatibility with the upcoming release of
Python 3.13. Most changes are related to the implementation of type
parameter defaults (PEP 696).

Thanks to all of the people who contributed patches, especially Alex
Waygood, who did most of the work adapting typing-extensions to the
CPython PEP 696 implementation.

Full changelog:

• Improve the implementation of type parameter defaults (PEP 696)
  • 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 a default value for a ParamSpec
    would be cast to a tuple if a list was provided.
    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.
• Releases are now made using Trusted Publishers
  improving the security of the release process. Patch by Jelle Zijlstra.

4.12.0a2

This is another alpha release to test the new release workflow.

4.12.0a1

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.

4.11.0

Release 4.11.0 (April 5, 2024)

This feature release provides improvements to various recently
added features, most importantly type parameter defaults (PEP 696).

There are no changes since 4.11.0rc1.

Changes since 4.10.0:

• Fix tests on Python 3.13.0a5. Patch by Jelle Zijlstra.
• Fix the runtime behavior of type parameters with defaults (PEP 696).
  Patch by Nadir Chowdhury.
• Fix minor discrepancy between error messages produced by typing
  and typing_extensions on Python 3.10. Patch by Jelle Zijlstra.
• When include_extra=False, get_type_hints() now strips ReadOnly from the annotation.

4.11.0rc1

• Fix tests on Python 3.13.0a5. Patch by Jelle Zijlstra.
• Fix the runtime behavior of type parameters with defaults (PEP 696).
  Patch by Nadir Chowdhury.
• Fix minor discrepancy between error messages produced by typing
  and typing_extensions on Python 3.10. Patch by Jelle Zijlstra.
• When include_extra=False, get_type_hints() now strips ReadOnly from the annotation.

4.10.0

Release 4.10.0 (February 25, 2024)

This feature release adds support for PEP 728 (TypedDict with extra
items) and PEP 742 (TypeIs).

There are no changes since 4.10.0rc1.

4.10.0rc1

Release 4.10.0rc1 (February 17, 2024)

• Add support for PEP 728, supporting the closed keyword argument and the
  special __extra_items__ key for TypedDict. Patch by Zixuan James Li.
• Add support for PEP 742, adding typing_extensions.TypeIs. Patch
  by Jelle Zijlstra.
• Drop runtime error when a read-only TypedDict item overrides a mutable
  one. Type checkers should still flag this as an error. Patch by Jelle
  Zijlstra.
• Speedup issubclass() checks against simple runtime-checkable protocols by
  around 6% (backporting python/cpython#112717, by Alex
  Waygood).
• Fix a regression in the implementation of protocols where typing.Protocol
  classes that were not marked as @runtime_checkable would be unnecessarily
  introspected, potentially causing exceptions to be raised if the protocol had
  problematic members. Patch by Alex Waygood, backporting
  python/cpython#113401.

4.9.0

This feature release adds typing_extensions.ReadOnly, as specified
by PEP 705, and makes various other improvements, especially to
@typing_extensions.deprecated().

There are no changes since 4.9.0rc1.