Summary of Pybind11 Version 3.0.0 RC 1

[pchsu-hsupc]

Summary of Pybind11 Version 3.0.0 RC 1 ,

This is a large release, so they are issuing a release candidate that will be phased in over about a week. And also provide SPEC 4 nightly wheels. Pybind 11 3.0 includes an ABI bump on Unix. This release retains the deprecated features but will not carry them forward into upcoming 3.x release.

New features

• Enabling py::class_<T, py::smart_holder> to handle two-way conversion with std::unique_ptr<T> and std::shared_ptr<T> and disowning a Python object being passed to std::unique_ptr<T>, trampoline objects, and std::enable_shared_from_this
• Adjusting PYBIND11_MODULE and PYBIND11_EMBEDDED_MODULE macro
• Support for sub-interpreters with py::multiple_interpreters::per_interpreter_gil(), and provide API from subinterpreter.h
• py::native_enum is used to convert between Python enums and C++ enums
• Adding py::release_gil_before_calling_cpp_dtor , dtype::normalized_num, dtype::num_of array_t<handle>, and array_t<object>
• Python warnings gets 2 more namespaces py::warnings::warn and py::warnings::new_warning_type
• In stl.h, list|set|map_caster do not need to explicitly transform Python iterables into tuple(), set(), or map()
• array_caster now can support non-default-constructible
• pybind11/conduit/pybind11_platform_abi_id.h was factored out for using PYBIND11_PLATFORM_ABI_ID
• Using pkgconf to find pybind11 on Pypi.
• pybind11 adding —extension-suffix
• Adding pybind11::detail::is_holder_constructed

New features (typing / hints)

• Make std::function match Callable type
• Add attr_with_type for declaring attribute types and Final, ClassVar type annotations
• Use py::pos_only to mark functions with only self as positional-only; dunder methods are auto-marked likewise.
• Using numpy.object_ instead of object
• py::Args and py::KWArgs provide *args and **kwargs custom type hinting
• collections.abc can be used in type hints，and convertible checks of STL casters and py::buffer

Removals

• Remove support for pybind11 v2 internals versions（4, 5, 6）and be bumped in pybind11 v3
• Remove make_simple_namespace
• Remove legacy-mode optionPYBIND11_NUMPY_1_ONLY

Bug fixes

• submodules has __file__
• pybind11-bound functions are pickleable
• Using-Wmaybe-uninitialized in eigen/matrix.h to turn off warnings
• py::args and py::kwargs can have subclasses
• __cpp_nontype_template_args replace __cpp_nontype_template_parameter_class
• When restoring pickle, updating dict instead assigning new.
• Define _DEBUG to 1
• py::slice's constructor behaves same as :: in Python

Bug fixes (CMake)

• Cmake uses FindPython by default，and COMPAT mode can smooth the transition
• Use CMake's warnings as errors (CMake 3.24+)
• CMake 3.25+ can run pybind11's test by default and support --fresh
• venv supports --fresh

Bug fixes (free-threading)

• Fixed some data race issues related to free threads, and added a mutex in the try_translate_exceptions exception translator

Internals

• Consolidated the PYBIND11_HAS_... macros into pybind11/detail/common.h, and split gil_simple.h out from gil.h

Tests

• Enabled additional compiler warnings -Wwrite-strings, -Wunreachable-code, -Wpointer-arith, and -Wredundant-decls in some CI tests
• Added CI testing for PyPy 3.11

Platforms

• Support for Python 3.14, 3.14t, GraalPy, and PyPy 3.11
• Not suuport for Python 3.7, PyPy 3.8/3.9, and CMake <3.15
• PyPI uses scikit-build-core to build pybind11, and Cmake generation was changed to sdist→wheel stage.
• Removed PYBIND11_GLOBAL_SDIST

[pchsu-hsupc]

@yungyuc , please review this when you are free. Thanks.

[yungyuc]

Thank you. This is not concise enough to be a summary. Please make it concise and specific to modmesh. Do not use bullets.

[pchsu-hsupc]

OK, it will take me some time.