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