Version 2.10.3

Changes:

• Temporarily made our GIL status assertions (added in 2.10.2) disabled by default (re-enable manually by defining PYBIND11_ASSERT_GIL_HELD_INCREF_DECREF, will be enabled in 2.11). #4432
• Improved error messages when inc_ref/dec_ref are called with an invalid GIL state. #4427 #4436

Bug Fixes:

• Some minor touchups found by static analyzers. #4440

Version 2.10.2

Changes:

• scoped_interpreter constructor taking PyConfig. #4372
• pybind11/eigen/tensor.h adds converters to and from Eigen::Tensor and Eigen::TensorMap #4201
• PyGILState_Check()'s were integrated to pybind11::handle inc_ref() & dec_ref(). The added GIL checks are guarded by PYBIND11_ASSERT_GIL_HELD_INCREF_DECREF, which is the default only if NDEBUG is not defined. #4246
• Add option for enable/disable enum members in docstring. #2768
• Fixed typing of KeysView, ValuesView and ItemsView in bind_map. #4353

Bug fixes:

• Bug fix affecting only Python 3.6 under very specific, uncommon conditions: move PyEval_InitThreads() call to the correct location. #4350
• Fix segfault bug when passing foreign native functions to functional.h. #4254

Build system improvements:

• Support setting PYTHON_LIBRARIES manually for Windows ARM cross-compilation (classic mode). #4406
• Extend IPO/LTO detection for ICX (a.k.a IntelLLVM) compiler. #4402
• Allow calling find_package(pybind11 CONFIG) multiple times from separate directories in the same CMake project and properly link Python (new mode). #4401
• multiprocessing_set_spawn in pytest fixture for added safety. #4377
• Fixed a bug in two pybind11/tools cmake scripts causing "Unknown arguments specified" errors. #4327

Version 2.10.1

This is the first version to fully support embedding the newly released Python 3.11.

Changes:

• Allow pybind11::capsule constructor to take null destructor pointers. #4221
• embed.h was changed so that PYTHONPATH is used also with Python 3.11 (established behavior). #4119
• A PYBIND11_SIMPLE_GIL_MANAGEMENT option was added (cmake, C++ define), along with many additional tests in test_gil_scoped.py. The option may be useful to try when debugging GIL-related issues, to determine if the more complex default implementation is or is not to blame. See #4216 for background. WARNING: Please be careful to not create ODR violations when using the option: everything that is linked together with mutual symbol visibility needs to be rebuilt. #4216
• PYBIND11_EXPORT_EXCEPTION was made non-empty only under macOS. This makes Linux builds safer, and enables the removal of warning suppression pragmas for Windows. #4298

Bug fixes:

• Fixed a bug where UnicodeDecodeError was not propagated from various py::str ctors when decoding surrogate utf characters. #4294
• Revert perfect forwarding for make_iterator. This broke at least one valid use case. May revisit later. #4234
• Fix support for safe casts to void* (regression in 2.10.0). #4275
• Fix char8_t support (regression in 2.9). #4278
• Unicode surrogate character in Python exception message leads to process termination in error_already_set::what(). #4297
• Fix MSVC 2019 v.1924 & C++14 mode error for overload_cast. #4188
• Make augmented assignment operators non-const for the object-api. Behavior was previously broken for augmented assignment operators. #4065
• Add proper error checking to C++ bindings for Python list append and insert. #4208
• Work-around for Nvidia's CUDA nvcc compiler in versions 11.4.0 - 11.8.0. #4220
• A workaround for PyPy was added in the py::error_already_set implementation, related to PR #1895 released with v2.10.0. #4079
• Fixed compiler errors when C++23 std::forward_like is available. #4136
• Properly raise exceptions in contains methods (like when an object in unhashable). #4209
• Further improve another error in exception handling. #4232
• get_local_internals() was made compatible with finalize_interpreter(), fixing potential freezes during interpreter finalization. #4192

Performance and style:

• Reserve space in set and STL map casters if possible. This will prevent unnecessary rehashing / resizing by knowing the number of keys ahead of time for Python to C++ casting. This improvement will greatly speed up the casting of large unordered maps and sets. #4194
• GIL RAII scopes are non-copyable to avoid potential bugs. #4183
• Explicitly default all relevant ctors for pytypes in the PYBIND11_OBJECT macros and enforce the clang-tidy checks modernize-use-equals-default in macros as well. #4017
• Optimize iterator advancement in C++ bindings. #4237
• Use the modern PyObject_GenericGetDict and PyObject_GenericSetDict for handling dynamic attribute dictionaries. #4106
• Document that users should use PYBIND11_NAMESPACE instead of using pybind11 when opening namespaces. Using namespace declarations and namespace qualification remain the same as pybind11. This is done to ensure consistent symbol visibility. #4098
• Mark detail::forward_like as constexpr. #4147
• Optimize unpacking_collector when processing arg_v arguments. #4219
• Optimize casting C++ object to None. #4269

Build system improvements:

• CMake: revert overwrite behavior, now opt-in with PYBIND11_PYTHONLIBS_OVERRWRITE OFF. #4195
• Include a pkg-config file when installing pybind11, such as in the Python package. #4077
• Avoid stripping debug symbols when CMAKE_BUILD_TYPE is set to DEBUG instead of Debug. #4078
• Followup to #3948, fixing vcpkg again. #4123

Version 2.10.0

Removed support for Python 2.7, Python 3.5, and MSVC 2015. Support for MSVC 2017 is limited due to availability of CI runners; we highly recommend MSVC 2019 or 2022 be used. Initial support added for Python 3.11.

New features:

• py::anyset & py::frozenset were added, with copying (cast) to std::set (similar to set). #3901
• Support bytearray casting to string. #3707
• type_caster<std::monostate> was added. std::monostate is a tag type that allows std::variant to act as an optional, or allows default construction of a std::variant holding a non-default constructible type. #3818
• pybind11::capsule::set_name added to mutate the name of the capsule instance. #3866
• NumPy: dtype constructor from type number added, accessors corresponding to Python API dtype.num, dtype.byteorder, dtype.flags and dtype.alignment added. #3868

Changes:

• Python 3.6 is now the minimum supported version. #3688 #3719
• The minimum version for MSVC is now 2017. #3722
• Fix issues with CPython 3.11 betas and add to supported test matrix. #3923
• error_already_set is now safer and more performant, especially for exceptions with long tracebacks, by delaying computation. #1895
• Improve exception handling in python str bindings. #3826
• The bindings for capsules now have more consistent exception handling. #3825
• PYBIND11_OBJECT_CVT and PYBIND11_OBJECT_CVT_DEFAULT macro can now be used to define classes in namespaces other than pybind11. #3797
• Error printing code now uses PYBIND11_DETAILED_ERROR_MESSAGES instead of requiring NDEBUG, allowing use with release builds if desired. #3913
• Implicit conversion of the literal 0 to pybind11::handle is now disabled. #4008

Bug fixes:

• Fix exception handling when pybind11::weakref() fails. #3739
• module_::def_submodule was missing proper error handling. This is fixed now. #3973
• The behavior or error_already_set was made safer and the highly opaque "Unknown internal error occurred" message was replaced with a more helpful message. #3982
• error_already_set::what() now handles non-normalized exceptions correctly. #3971
• Support older C++ compilers where filesystem is not yet part of the standard library and is instead included in std::experimental::filesystem. #3840
• Fix -Wfree-nonheap-object warnings produced by GCC by avoiding returning pointers to static objects with return_value_policy::take_ownership. #3946
• Fix cast from pytype rvalue to another pytype. #3949
• Ensure proper behavior when garbage collecting classes with dynamic attributes in Python >=3.9. #4051
• A couple long-standing PYBIND11_NAMESPACE __attribute__((visibility("hidden"))) inconsistencies are now fixed (affects only unusual environments). #4043
• pybind11::detail::get_internals() is now resilient to in-flight Python exceptions. #3981
• Arrays with a dimension of size 0 are now properly converted to dynamic Eigen matrices (more common in NumPy 1.23). #4038
• Avoid catching unrelated errors when importing NumPy. #3974

Performance and style:

• Added an accessor overload of (object &&key) to reference steal the object when using python types as keys. This prevents unnecessary reference count overhead for attr, dictionary, tuple, and sequence look ups. Added additional regression tests. Fixed a performance bug the caused accessor assignments to potentially perform unnecessary copies. #3970
• Perfect forward all args of make_iterator. #3980
• Avoid potential bug in pycapsule destructor by adding an error_guard to one of the dtors. #3958
• Optimize dictionary access in strip_padding for numpy. #3994
• stl_bind.h bindings now take slice args as a const-ref. #3852
• Made slice constructor more consistent, and improve performance of some casters by allowing reference stealing. #3845
• Change numpy dtype from_args method to use const ref. #3878
• Follow rule of three to ensure PyErr_Restore is called only once. #3872
• Added missing perfect forwarding for make_iterator functions. #3860
• Optimize c++ to python function casting by using the rvalue caster. #3966
• Optimize Eigen sparse matrix casting by removing unnecessary temporary. #4064
• Avoid potential implicit copy/assignment constructors causing double free in strdup_gaurd. #3905
• Enable clang-tidy checks misc-definitions-in-headers, modernize-loop-convert, and modernize-use-nullptr. #3881 #3988

Build system improvements:

• CMake: Fix file extension on Windows with cp36 and cp37 using FindPython. #3919
• CMake: Support multiple Python targets (such as on vcpkg). #3948
• CMake: Fix issue with NVCC on Windows. #3947
• CMake: Drop the bitness check on cross compiles (like targeting WebAssembly via Emscripten). #3959
• Add MSVC builds in debug mode to CI. #3784
• MSVC 2022 C++20 coverage was added to GitHub Actions, including Eigen. #3732, #3741

Backend and tidying up:

• New theme for the documentation. #3109
• Remove idioms in code comments. Use more inclusive language. #3809
• #include <iostream> was removed from the pybind11/stl.h header. Your project may break if it has a transitive dependency on this include. The fix is to "Include What You Use". #3928
• Avoid setup.py <command> usage in internal tests. #3734

Version 2.9.2

Changes:

• Enum now has an __index__ method on Python <3.8 too. #3700
• Local internals are now cleared after finalizing the interpreter. #3744

Bug fixes:

• Better support for Python 3.11 alphas. #3694
• PYBIND11_TYPE_CASTER now uses fully qualified symbols, so it can be used outside of pybind11::detail. #3758
• Some fixes for PyPy 3.9. #3768
• Fixed a potential memleak in PyPy in get_type_override. #3774
• Fix usage of VISIBILITY_INLINES_HIDDEN. #3721

Build system improvements:

• Uses sysconfig module to determine installation locations on Python >= 3.10, instead of distutils which has been deprecated. #3764
• Support Catch 2.13.5+ (supporting GLIBC 2.34+). #3679
• Fix test failures with numpy 1.22 by ignoring whitespace when comparing str() of dtypes. #3682

Backend and tidying up:

• clang-tidy: added readability-qualified-auto, readability-braces-around-statements, cppcoreguidelines-prefer-member-initializer, clang-analyzer-optin.performance.Padding, cppcoreguidelines-pro-type-static-cast-downcast, and readability-inconsistent-declaration-parameter-name. #3702, #3699, #3716, #3709
• clang-format was added to the pre-commit actions, and the entire code base automatically reformatted (after several iterations preparing for this leap). #3713

Version 2.9.1

Changes:

• If possible, attach Python exception with py::raise_from to TypeError when casting from C++ to Python. This will give additional info if Python exceptions occur in the caster. Adds a test case of trying to convert a set from C++ to Python when the hash function is not defined in Python. #3605
• Add a mapping of C++11 nested exceptions to their Python exception equivalent using py::raise_from. This attaches the nested exceptions in Python using the __cause__ field. #3608
• Propagate Python exception traceback using raise_from if a pybind11 function runs out of overloads. #3671
• py::multiple_inheritance is now only needed when C++ bases are hidden from pybind11. #3650 and #3659

Bug fixes:

• Remove a boolean cast in numpy.h that causes MSVC C4800 warnings when compiling against Python 3.10 or newer. #3669
• Render py::bool_ and py::float_ as bool and float respectively. #3622

Build system improvements:

• Fix CMake extension suffix computation on Python 3.10+. #3663
• Allow CMAKE_ARGS to override CMake args in pybind11's own setup.py. #3577
• Remove a few deprecated c-headers. #3610
• More uniform handling of test targets. #3590
• Add clang-tidy readability check to catch potentially swapped function args. #3611

Version 2.9.0

This is the last version to support Python 2.7 and 3.5.

New Features:

• Allow py::args to be followed by other arguments; the remaining arguments are implicitly keyword-only, as if a py::kw_only{} annotation had been used. #3402

Changes:

• Make str/bytes/memoryview more interoperable with std::string_view. #3521
• Replace _ with const_name in internals, avoid defining pybind::_ if _ defined as macro (common gettext usage) #3423

Bug fixes:

• Fix a rare warning about extra copy in an Eigen constructor. #3486
• Fix caching of the C++ overrides. #3465
• Add missing std::forward calls to some cpp_function overloads. #3443
• Support PyPy 7.3.7 and the PyPy3.8 beta. Test python-3.11 on PRs with the python dev label. #3419
• Replace usage of deprecated Eigen::MappedSparseMatrix with Eigen::Map<Eigen::SparseMatrix<...>> for Eigen 3.3+. #3499
• Tweaks to support Microsoft Visual Studio 2022. #3497

Build system improvements:

• Nicer CMake printout and IDE organisation for pybind11's own tests. #3479
• CMake: report version type as part of the version string to avoid a spurious space in the package status message. #3472
• Flags starting with -g in $CFLAGS and $CPPFLAGS are no longer overridden by .Pybind11Extension. #3436
• Ensure ThreadPool is closed in setup_helpers. #3548
• Avoid LTS on mips64 and ppc64le (reported broken). #3557

Version 2.8.1

v2.8.1 (Oct 27, 2021)

Changes and additions:

• The simple namespace creation shortcut added in 2.8.0 was deprecated due to usage of CPython internal API, and will be removed soon. Use py::module_::import("types").attr("SimpleNamespace"). #3374
• Add C++ Exception type to throw and catch AttributeError. Useful for defining custom __setattr__ and __getattr__ methods. #3387

Fixes:

• Fixed the potential for dangling references when using properties with std::optional types. #3376
• Modernize usage of PyCodeObject on Python 3.9+ (moving toward support for Python 3.11a1) #3368
• A long-standing bug in eigen.h was fixed (originally PR #3343). The bug was unmasked by newly added static_assert's in the Eigen 3.4.0 release. #3352
• Support multiple raw inclusion of CMake helper files (Conan.io does this for multi-config generators). #3420
• Fix harmless warning on upcoming CMake 3.22. #3368
• Fix 2.8.0 regression with MSVC 2017 + C++17 mode + Python 3. #3407
• Fix 2.8.0 regression that caused undefined behavior (typically segfaults) in make_key_iterator/make_value_iterator if dereferencing the iterator returned a temporary value instead of a reference. #3348

Version 2.8.0

New features:

• Added py::raise_from to enable chaining exceptions. #3215
• Allow exception translators to be optionally registered local to a module instead of applying globally across all pybind11 modules. Use register_local_exception_translator(ExceptionTranslator&& translator) instead of register_exception_translator(ExceptionTranslator&& translator) to keep your exception remapping code local to the module. #2650
• Add make_simple_namespace function for instantiating Python SimpleNamespace objects. #2840
• pybind11::scoped_interpreter and initialize_interpreter have new arguments to allow sys.argv initialization. #2341
• Allow Python builtins to be used as callbacks in CPython. #1413
• Added view to view arrays with a different datatype. #987
• Implemented reshape on arrays. #984
• Enable defining custom __new__ methods on classes by fixing bug preventing overriding methods if they have non-pybind11 siblings. #3265
• Add make_value_iterator(), and fix make_key_iterator() to return references instead of copies. #3293
• Improve the classes generated by bind_map: #3310
  • Change .items from an iterator to a dictionary view.
  • Add .keys and .values (both dictionary views).
  • Allow __contains__ to take any object.
• pybind11::custom_type_setup was added, for customizing the PyHeapTypeObject corresponding to a class, which may be useful for enabling garbage collection support, among other things. #3287

Changes:

• Set __file__ constant when running eval_file in an embedded interpreter. #3233
• Python objects and (C++17) std::optional now accepted in py::slice constructor. #1101
• The pybind11 proxy types str, bytes, bytearray, tuple, list now consistently support passing ssize_t values for sizes and indexes. Previously, only size_t was accepted in several interfaces. #3219
• Avoid evaluating PYBIND11_TLS_REPLACE_VALUE arguments more than once. #3290

Fixes:

• Bug fix: enum value's __int__ returning non-int when underlying type is bool or of char type #1334
• Fixes bug in setting error state in Capsule's pointer methods. #3261
• A long-standing memory leak in py::cpp_function::initialize was fixed. #3229
• Fixes thread safety for some pybind11::type_caster which require lifetime extension, such as for std::string_view. #3237
• Restore compatibility with gcc 4.8.4 as distributed by ubuntu-trusty, linuxmint-17. #3270

Build system improvements:

• Fix regression in CMake Python package config: improper use of absolute path. #3144
• Cached Python version information could become stale when CMake was re-run with a different Python version. The build system now detects this and updates this information. #3299
• Specified UTF8-encoding in setup.py calls of open(). #3137
• Fix a harmless warning from CMake 3.21 with the classic Python discovery. #3220
• Eigen repo and version can now be specified as cmake options. #3324

Backend and tidying up:

• Reduced thread-local storage required for keeping alive temporary data for type conversion to one key per ABI version, rather than one key per extension module. This makes the total thread-local storage required by pybind11 2 keys per ABI version. #3275
• Optimize NumPy array construction with additional moves. #3183
• Conversion to std::string and std::string_view now avoids making an extra copy of the data on Python >= 3.3. #3257
• Remove const modifier from certain C++ methods on Python collections (list, set, dict) such as (clear(), append(), insert(), etc...) and annotated them with py-non-const.
• Enable readability clang-tidy-const-return and remove useless consts. #3254 #3194
• The clang-tidy google-explicit-constructor option was enabled. #3250
• Mark a pytype move constructor as noexcept (perf). #3236
• Enable clang-tidy check to guard against inheritance slicing. #3210
• Legacy warning suppression pragma were removed from eigen.h. On Unix platforms, please use -isystem for Eigen include directories, to suppress compiler warnings originating from Eigen headers. Note that CMake does this by default. No adjustments are needed for Windows. #3198
• Format pybind11 with isort consistent ordering of imports #3195
• The warnings-suppression "pragma clamp" at the top/bottom of pybind11 was removed, clearing the path to refactoring and IWYU cleanup. #3186
• Enable most bugprone checks in clang-tidy and fix the found potential bugs and poor coding styles. #3166
• Add clang-tidy-readability rules to make boolean casts explicit improving code readability. Also enabled other misc and readability clang-tidy checks. #3148
• Move object in .pop() for list. #3116

Version 2.7.1

Minor missing functionality added:

• Allow Python builtins to be used as callbacks in CPython. #1413

Bug fixes:

• Fix regression in CMake Python package config: improper use of absolute path. #3144
• Fix Mingw64 and add to the CI testing matrix. #3132
• Specified UTF8-encoding in setup.py calls of open(). #3137
• Add clang-tidy-readability rules to make boolean casts explicit improving code readability. Also enabled other misc and readability clang-tidy checks. #3148
• Move object in .pop() for list. #3116

Backend and tidying up:

• Removed and fixed warning suppressions. #3127 #3129 #3135 #3141 #3142 #3150 #3152 #3160 #3161