github pybind/pybind11 v3.0.0rc1
Version 3.0.0 RC 1
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latest releases: v3.0.1, v3.0.0, v3.0.0rc4...
pre-release3 months ago

What's Changed

Since this is a large release, we are providing a release candidate to give projects time to test! We also now provide SPEC 4 nightly wheels. We are hoping to split up std.h; that work is approved to be added during the RC phase if it's ready in time. We expect the RC phase to last around a week.

Pybind11 3.0 includes an ABI bump, the first required bump in many years on Unix (Windows has had required bumps more often). This release contains the smart-holder branch, multi-phase init and subinterpreter support, py::native_enum, an interface to warnings, typing improvements, and more. CMake now defaults to FindPython mode. Please check our upgrade guide for more info on upgrading!

Support for Python 3.14, 3.14t, GraalPy, and PyPy 3.11 has been added, while legacy support for Python 3.7, PyPy 3.8/3.9, and CMake <3.15 has been removed. Most deprecated features have been kept for this release, but anything producing a warning in 3.0 may be removed in a future 3.x version. We also now have a deprecation page.

New Features:

  • The smart_holder branch has been merged, enabling py::class_<T, py::smart_holder>, which handles two-way conversion
    with std::unique_ptr<T> and std::shared_ptr<T> (simultaneously), disowning a Python object being passed to std::unique_ptr<T>, trampoline objects, and std::enable_shared_from_this. #5542
  • Changed PYBIND11_MODULE macro implementation to perform multi-phase module initialization (PEP 489) behind the scenes. #5574
  • Support for sub-interpreters (both isolated (with separate GILs) and legacy (with a global GIL). Add the
    py::multiple_interpreters::per_interpreter_gil() tag (or, py::multiple_interpreters::shared_gil() for legacy interpreter
    support) to PYBIND11_MODULE calls (as the third parameter) to indicate that a module supports running with sub-interpreters. #5564
  • Changed PYBIND11_EMBEDDED_MODULE macro implementation to perform multi-phase module initialization (PEP 489) behind the scenes and to support py::mod_gil_not_used(), py::multiple_interpreters::per_interpreter_gil() and py::multiple_interpreters::shared_gil(). #5665 and consolidate code #5670
  • Added API in pybind11/subinterpreter.h for embedding sub-intepreters (requires Python 3.12+). #5666
  • py::native_enum was added, for conversions between Python's native (stdlib) enum types and C++ enums. #5555
    • Add class doc string to py::native_enum. #5617.
    • Fix signature for functions with a native_enum in the signature. #5619
  • A py::release_gil_before_calling_cpp_dtor option (for py::class_) was added to resolve the long-standing issue #1446. #5522
  • Add dtype::normalized_num and dtype::num_of. #5429
  • Add support for array_t<handle> and array_t<object>. #5427
  • Added py::warnings namespace with py::warnings::warn and py::warnings::new_warning_type that provides the interface for
    Python warnings. #5291
  • stl.h list|set|map_caster were made more user friendly: it is no longer necessary to explicitly convert Python iterables to tuple(),
    set(), or map() in many common situations. #4686
  • The array_caster in pybind11/stl.h was enhanced to support value types that are not default-constructible. #5305
  • pybind11/conduit/pybind11_platform_abi_id.h was factored out, to maximize reusability of PYBIND11_PLATFORM_ABI_ID (for other Python/C++ binding systems). #5375
  • Added support for finding pybind11 using pkgconf distributed on pypi. #5552
  • Support --extension-suffix on the pybind11 command. #5360
  • Add semi-public API: pybind11::detail::is_holder_constructed and update example for pybind11::custom_type_setup in documentation. #5669

New Features / fixes (typing):

  • Added option for different arg/return type hints to type_caster. Updated stl/filesystem to use correct arg/return type hints. Updated pybind11::typing to use correct arg/return type hints for nested types. #5450
  • Updated type hint for py::capsule to type.CapsuleType. #5567
  • Adds support for typing.SupportsInt and typing.SupportsFloat. Update Final to be narrower type hint. Make std::function match Callable type. Fix io_name bug in attr_with_type_hint. #5540
  • Rework of arg/return type hints to support .noconvert(). #5486
  • Add attr_with_type for declaring attribute types and Final, ClassVar type annotations. #5460
  • Allow annotate methods with py::pos_only when only have the self argument. Make arguments for auto-generated dunder methods positional-only. #5403
  • Added py::Args and py::KWArgs to enable custom type hinting of *args and **kwargs (see PEP 484). #5357
  • Switched to numpy.typing.NDArray and numpy.typing.ArrayLike. #5212
  • Use numpy.object_ instead of object. #5571
  • Fix module type hint. #5469
  • Fix Buffer type hint. #5662
  • Added support for collections.abc in type hints and convertible checks of STL casters and py::buffer.
    #5566
  • Fix typing and collections.abc type hint ambiguity. #5663

Removals:

  • Remove support for pybind11 v2 internals versions (4, 5, 6). (The internals version number has been bumped for pybind11 v3.) #5512 | #5530
  • Remove make_simple_namespace (added in 2.8.0, deprecated in 2.8.1). #5597
  • Legacy-mode option PYBIND11_NUMPY_1_ONLY has been removed. #5595
  • Add a deprecation warning to .get_type (deprecated in pybind11 2.6 in 2020). #5596

Bug fixes:

  • Set __file__ on submodules. #5584. Except on
    embedded modules. #5650
  • pybind11-bound functions are now pickleable. #5580
  • Fix bug in attr_with_type_hint to allow objects to be in attr_with_type_hint. #5576
  • A -Wmaybe-uninitialized warning suppression was added in pybind11/eigen/matrix.h. #5516
  • PYBIND11_WARNING_POP was incorrectly defined as PYBIND11_PRAGMA(clang diagnostic push). #5448
  • PYBIND11_PLATFORM_ABI_ID (which is used in composing PYBIND11_INTERNALS_ID) was modernized to reflect actual ABI
    compatibility more accurately. #4953 | #5439
  • Fix buffer protocol implementation. #5407
  • Fix iterator increment operator does not skip first item. #5400
  • When getting or deleting an element in a container bound by bind_map, print the key in KeyError if it does not exist. #5397
  • pybind11::builtin_exception is now explicitly exported when linked to libc++. #5390
  • Allow subclasses of py::args and py::kwargs. #5381
  • Disable false-positive GCC 12 Bound Check warning. #5355
  • fix: using __cpp_nontype_template_args instead of __cpp_nontype_template_parameter_class. #5330
  • Properly translate C++ exception to Python exception when creating Python buffer from wrapped object. #5324
  • Update the dict when restoring pickles, instead of assigning a replacement dict. #5658
  • Properly define _DEBUG macro to 1 instead of defining it without value. #5639
  • Fix a missing time cast causing a compile error for newer ICC. #5621
  • Change the behavior of the default constructor of py::slice to be equivalent to :: in Python. #5620

Bug fixes (CMake):

  • Enable FindPython mode by default, with a COMPAT mode that sets some of the old variables to ease transition. #5553
  • Add an author warning that auto-calculated PYTHON_MODULE_EXTENSION may not respect SETUPTOOLS_EXT_SUFFIX during cross-compilation. #5495
  • Don't strip with CMAKE_BUILD_TYPE None. #5392
  • Fix an issue with NO_EXTRAS adding pybind11::windows_extras anyway. #5378
  • Fix issue with NEW/OLD message showing up. #5656
  • Use CMake's warnings as errors if available (CMake 3.24+). #5612
  • Add support for running pybind11's tests via presets in CMake 3.25+. #5655 and support --fresh. #5668
  • Restructure venv support to support --fresh, make in build folder. #5668

Bug fixes (free-threading):

  • Fix data race in free threaded CPython when accessing a shared static variable. #5494
  • A free-threading data race in all_type_info() was fixed. #5419
  • Added exception translator specific mutex used with try_translate_exceptions in the free-threaded build for internal
    locking. #5362

Internals:

  • Consolidated all PYBIND11_HAS_... feature macros into pybind11/detail/common.h to streamline backward compatibility checks and simplify internal refactoring. This change ensures consistent macro availability regardless of header inclusion order. #5647
  • pybind11/gil_simple.h was factored out from pybind11/gil.h, so that it can easily be reused. #5614

Documentation:

  • Improved reference_internal policy documentation. #5528
  • A new "Double locking, deadlocking, GIL" document was added. #5394
  • Adds an answer (FAQ) for "What is a highly conclusive and simple way to find memory leaks?". #5340
  • Add documenting for free-threading and subinterpreters. #5659

Tests:

  • Download the final Catch2 2.x release if Catch download is requested. #5568
  • Explicitly used signed char for two numpy dtype tests. As seen when compiling using clang on Linux with the -funsigned-char flag. #5545
  • Test PyPy3.11 in CI. #5534
  • CI testing now includes -Wwrite-strings -Wunreachable-code -Wpointer-arith -Wredundant-decls in some jobs. #5523
  • Add nightly wheels to scientific-python's nightly wheelhouse. #5675

New and removed platforms:

  • Support Python 3.14 (beta 1). #5646
  • Added support for GraalPy Python implementation (https://github.com/oracle/graalpython). #5380
  • Support for PyPy 3.11 added. #5508
  • Support for PyPy 3.8 and 3.9 was dropped. #5578
  • Support for Python 3.7 was removed. (Official end-of-life: 2023-06-27). #5191
  • Support for CMake older than 3.15 removed. CMake 3.15-4.0 supported. #5304
  • Use scikit-build-core for the build backend for the PyPI pybind11. The CMake generation has been moved to the sdist->wheel step.
    PYBIND11_GLOBAL_SDIST has been removed. #5598 and updated
    docs/ci. #5676

New Contributors

Full Changelog: v2.13.6...v3.0.0rc1

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