Merge branch 'master' into sh_merge_master

.github/workflows/ci.yml

@@ -109,12 +109,15 @@ jobs:
       run: python -m pip install pytest-github-actions-annotate-failures
 
     # First build - C++11 mode and inplace
-    # More-or-less randomly adding -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON here.
+    # More-or-less randomly adding -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON here
+    # (same for PYBIND11_NUMPY_1_ONLY, but requires a NumPy 1.x at runtime).
     - name: Configure C++11 ${{ matrix.args }}
       run: >
         cmake -S . -B .
         -DPYBIND11_WERROR=ON
+        -DPYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION=ON
         -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
+        -DPYBIND11_NUMPY_1_ONLY=ON
         -DDOWNLOAD_CATCH=ON
         -DDOWNLOAD_EIGEN=ON
         -DCMAKE_CXX_STANDARD=11
@@ -139,11 +142,13 @@ jobs:
 
     # Second build - C++17 mode and in a build directory
     # More-or-less randomly adding -DPYBIND11_SIMPLE_GIL_MANAGEMENT=OFF here.
+    # (same for PYBIND11_NUMPY_1_ONLY, but requires a NumPy 1.x at runtime).
     - name: Configure C++17
       run: >
         cmake -S . -B build2
         -DPYBIND11_WERROR=ON
         -DPYBIND11_SIMPLE_GIL_MANAGEMENT=OFF
+        -DPYBIND11_NUMPY_1_ONLY=ON
         -DDOWNLOAD_CATCH=ON
         -DDOWNLOAD_EIGEN=ON
         -DCMAKE_CXX_STANDARD=17
@@ -661,6 +666,11 @@ jobs:
       run: |
         python3 -m pip install cmake -r tests/requirements.txt
 
+    - name: Ensure NumPy 2 is used (required Python >= 3.9)
+      if: matrix.container == 'almalinux:9'
+      run: |
+        python3 -m pip install 'numpy>=2.0.0b1' 'scipy>=1.13.0rc1'
+
     - name: Configure
       shell: bash
       run: >
@@ -896,8 +906,10 @@ jobs:
         python-version: ${{ matrix.python }}
 
     - name: Prepare env
+      # Ensure use of NumPy 2 (via NumPy nightlies but can be changed soon)
       run: |
         python3 -m pip install -r tests/requirements.txt
+        python3 -m pip install 'numpy>=2.0.0b1' 'scipy>=1.13.0rc1'
 
     - name: Update CMake
       uses: jwlawson/actions-setup-cmake@v2.0

.github/workflows/labeler.yml

@@ -14,7 +14,7 @@ jobs:
       pull-requests: write
     steps:
 
-    - uses: actions/labeler@main
+    - uses: actions/labeler@v4
       if: >
         github.event.pull_request.merged == true &&
         !startsWith(github.event.pull_request.title, 'chore(deps):') &&

CMakeLists.txt

@@ -107,15 +107,25 @@ endif()
 option(PYBIND11_INSTALL "Install pybind11 header files?" ${PYBIND11_MASTER_PROJECT})
 option(PYBIND11_TEST "Build pybind11 test suite?" ${PYBIND11_MASTER_PROJECT})
 option(PYBIND11_NOPYTHON "Disable search for Python" OFF)
+option(PYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION
+       "To enforce that a handle_type_name<> specialization exists" OFF)
 option(PYBIND11_SIMPLE_GIL_MANAGEMENT
        "Use simpler GIL management logic that does not support disassociation" OFF)
+option(PYBIND11_NUMPY_1_ONLY
+       "Disable NumPy 2 support to avoid changes to previous pybind11 versions." OFF)
 set(PYBIND11_INTERNALS_VERSION
     ""
     CACHE STRING "Override the ABI version, may be used to enable the unstable ABI.")
 
+if(PYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION)
+  add_compile_definitions(PYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION)
+endif()
 if(PYBIND11_SIMPLE_GIL_MANAGEMENT)
   add_compile_definitions(PYBIND11_SIMPLE_GIL_MANAGEMENT)
 endif()
+if(PYBIND11_NUMPY_1_ONLY)
+  add_compile_definitions(PYBIND11_NUMPY_1_ONLY)
+endif()
 
 cmake_dependent_option(
   USE_PYTHON_INCLUDE_DIR

README.rst

@@ -40,10 +40,10 @@ with everything stripped away that isn't relevant for binding
 generation. Without comments, the core header files only require ~4K
 lines of code and depend on Python (3.6+, or PyPy) and the C++
 standard library. This compact implementation was possible thanks to
-some of the new C++11 language features (specifically: tuples, lambda
+some C++11 language features (specifically: tuples, lambda functions and
-functions and variadic templates). Since its creation, this library has
+variadic templates). Since its creation, this library has grown beyond
-grown beyond Boost.Python in many ways, leading to dramatically simpler
+Boost.Python in many ways, leading to dramatically simpler binding code in many
-binding code in many common situations.
+common situations.
 
 Tutorial and reference documentation is provided at
 `pybind11.readthedocs.io <https://pybind11.readthedocs.io/en/latest>`_.
@@ -75,6 +75,7 @@ pybind11 can map the following core C++ features to Python:
 - Internal references with correct reference counting
 - C++ classes with virtual (and pure virtual) methods can be extended
   in Python
+- Integrated NumPy support (NumPy 2 requires pybind11 2.12+)
 
 Goodies
 -------

docs/changelog.rst

@@ -15,9 +15,183 @@ IN DEVELOPMENT
 
 Changes will be summarized here periodically.
 
+Version 2.12.0 (March 27, 2025)
+-------------------------------
+
+New Features:
+
+* ``pybind11`` now supports compiling for
+  `NumPy 2 <https://numpy.org/devdocs/numpy_2_0_migration_guide.html>`_. Most
+  code shouldn't change (see :ref:`upgrade-guide-2.12` for details). However,
+  if you experience issues you can define ``PYBIND11_NUMPY_1_ONLY`` to disable
+  the new support for now, but this will be removed in the future.
+  `#5050 <https://github.com/pybind/pybind11/pull/5050>`_
+
+* ``pybind11/gil_safe_call_once.h`` was added (it needs to be included
+  explicitly). The primary use case is GIL-safe initialization of C++
+  ``static`` variables.
+  `#4877 <https://github.com/pybind/pybind11/pull/4877>`_
+
+* Support move-only iterators in ``py::make_iterator``,
+  ``py::make_key_iterator``, ``py::make_value_iterator``.
+  `#4834 <https://github.com/pybind/pybind11/pull/4834>`_
+
+* Two simple ``py::set_error()`` functions were added and the documentation was
+  updated accordingly. In particular, ``py::exception<>::operator()`` was
+  deprecated (use one of the new functions instead). The documentation for
+  ``py::exception<>`` was further updated to not suggest code that may result
+  in undefined behavior.
+  `#4772 <https://github.com/pybind/pybind11/pull/4772>`_
+
+Bug fixes:
+
+* Removes potential for Undefined Behavior during process teardown.
+  `#4897 <https://github.com/pybind/pybind11/pull/4897>`_
+
+* Improve compatibility with the nvcc compiler (especially CUDA 12.1/12.2).
+  `#4893 <https://github.com/pybind/pybind11/pull/4893>`_
+
+* ``pybind11/numpy.h`` now imports NumPy's ``multiarray`` and ``_internal``
+  submodules with paths depending on the installed version of NumPy (for
+  compatibility with NumPy 2).
+  `#4857 <https://github.com/pybind/pybind11/pull/4857>`_
+
+* Builtins collections names in docstrings are now consistently rendered in
+  lowercase (list, set, dict, tuple), in accordance with PEP 585.
+  `#4833 <https://github.com/pybind/pybind11/pull/4833>`_
+
+* Added ``py::typing::Iterator<T>``, ``py::typing::Iterable<T>``.
+  `#4832 <https://github.com/pybind/pybind11/pull/4832>`_
+
+* Render ``py::function`` as ``Callable`` in docstring.
+  `#4829 <https://github.com/pybind/pybind11/pull/4829>`_
+
+* Also bump ``PYBIND11_INTERNALS_VERSION`` for MSVC, which unlocks two new
+  features without creating additional incompatibilities.
+  `#4819 <https://github.com/pybind/pybind11/pull/4819>`_
+
+* Guard against crashes/corruptions caused by modules built with different MSVC
+  versions.
+  `#4779 <https://github.com/pybind/pybind11/pull/4779>`_
+
+* A long-standing bug in the handling of Python multiple inheritance was fixed.
+  See PR #4762 for the rather complex details.
+  `#4762 <https://github.com/pybind/pybind11/pull/4762>`_
+
+* Fix ``bind_map`` with ``using`` declarations.
+  `#4952 <https://github.com/pybind/pybind11/pull/4952>`_
+
+* Qualify ``py::detail::concat`` usage to avoid ADL selecting one from
+  somewhere else, such as modernjson's concat.
+  `#4955 <https://github.com/pybind/pybind11/pull/4955>`_
+
+* Use new PyCode API on Python 3.12+.
+  `#4916 <https://github.com/pybind/pybind11/pull/4916>`_
+
+* Minor cleanup from warnings reported by Clazy.
+  `#4988 <https://github.com/pybind/pybind11/pull/4988>`_
+
+* Remove typing and duplicate ``class_`` for ``KeysView``/``ValuesView``/``ItemsView``.
+  `#4985 <https://github.com/pybind/pybind11/pull/4985>`_
+
+* Use ``PyObject_VisitManagedDict()`` and ``PyObject_ClearManagedDict()`` on Python 3.13 and newer.
+  `#4973 <https://github.com/pybind/pybind11/pull/4973>`_
+
+* Update ``make_static_property_type()`` to make it compatible with Python 3.13.
+  `#4971 <https://github.com/pybind/pybind11/pull/4971>`_
+
+.. fix(types)
+
+* Render typed iterators for ``make_iterator``, ``make_key_iterator``,
+  ``make_value_iterator``.
+  `#4876 <https://github.com/pybind/pybind11/pull/4876>`_
+
+* Add several missing type name specializations.
+  `#5073 <https://github.com/pybind/pybind11/pull/5073>`_
+
+* Change docstring render for ``py::buffer``, ``py::sequence`` and
+  ``py::handle`` (to ``Buffer``, ``Sequence``, ``Any``).
+  `#4831 <https://github.com/pybind/pybind11/pull/4831>`_
+
+* Fixed ``base_enum.__str__`` docstring.
+  `#4827 <https://github.com/pybind/pybind11/pull/4827>`_
+
+* Enforce single line docstring signatures.
+  `#4735 <https://github.com/pybind/pybind11/pull/4735>`_
+
+* Special 'typed' wrappers now available in ``typing.h`` to annotate tuple, dict,
+  list, set, and function.
+  `#4259 <https://github.com/pybind/pybind11/pull/4259>`_
+
+* Create ``handle_type_name`` specialization to type-hint variable length tuples.
+  `#5051 <https://github.com/pybind/pybind11/pull/5051>`_
+
+.. fix(build)
+
+* Setting ``PYBIND11_FINDPYTHON`` to OFF will force the old FindPythonLibs mechanism to be used.
+  `#5042 <https://github.com/pybind/pybind11/pull/5042>`_
+
+* Skip empty ``PYBIND11_PYTHON_EXECUTABLE_LAST`` for the first cmake run.
+  `#4856 <https://github.com/pybind/pybind11/pull/4856>`_
+
+* Fix FindPython mode exports & avoid ``pkg_resources`` if
+  ``importlib.metadata`` available.
+  `#4941 <https://github.com/pybind/pybind11/pull/4941>`_
+
+* ``Python_ADDITIONAL_VERSIONS`` (classic search) now includes 3.12.
+  `#4909 <https://github.com/pybind/pybind11/pull/4909>`_
+
+* ``pybind11.pc`` is now relocatable by default as long as install destinations
+  are not absolute paths.
+  `#4830 <https://github.com/pybind/pybind11/pull/4830>`_
+
+* Correctly detect CMake FindPython removal when used as a subdirectory.
+  `#4806 <https://github.com/pybind/pybind11/pull/4806>`_
+
+* Don't require the libs component on CMake 3.18+ when using
+  PYBIND11_FINDPYTHON (fixes manylinux builds).
+  `#4805 <https://github.com/pybind/pybind11/pull/4805>`_
+
+* ``pybind11_strip`` is no longer automatically applied when
+  ``CMAKE_BUILD_TYPE`` is unset.
+  `#4780 <https://github.com/pybind/pybind11/pull/4780>`_
+
+* Support ``DEBUG_POSFIX`` correctly for debug builds.
+  `#4761 <https://github.com/pybind/pybind11/pull/4761>`_
+
+* Hardcode lto/thin lto for Emscripten cross-compiles.
+  `#4642 <https://github.com/pybind/pybind11/pull/4642>`_
+
+* Upgrade maximum supported CMake version to 3.27 to fix CMP0148 warnings.
+  `#4786 <https://github.com/pybind/pybind11/pull/4786>`_
+
+Documentation:
+
+* Small fix to grammar in ``functions.rst``.
+  `#4791 <https://github.com/pybind/pybind11/pull/4791>`_
+
+* Remove upper bound in example pyproject.toml for setuptools.
+  `#4774 <https://github.com/pybind/pybind11/pull/4774>`_
+
+CI:
+
+* CI: Update NVHPC to 23.5 and Ubuntu 20.04.
+  `#4764 <https://github.com/pybind/pybind11/pull/4764>`_
+
+* Test on PyPy 3.10.
+  `#4714 <https://github.com/pybind/pybind11/pull/4714>`_
+
+Other:
+
+* Use Ruff formatter instead of Black.
+  `#4912 <https://github.com/pybind/pybind11/pull/4912>`_
+
+* An ``assert()`` was added to help Coverty avoid generating a false positive.
+  `#4817 <https://github.com/pybind/pybind11/pull/4817>`_
+
 
 Version 2.11.1 (July 17, 2023)
------------------------------
+------------------------------
 
 Changes:
 
@@ -32,7 +206,7 @@ Changes:
 
 
 Version 2.11.0 (July 14, 2023)
------------------------------
+------------------------------
 
 New features:
 

docs/release.rst

@@ -36,19 +36,19 @@ If you don't have nox, you should either use ``pipx run nox`` instead, or use
 
   - Run ``nox -s tests_packaging`` to ensure this was done correctly.
 
-  - Ensure that all the information in ``setup.cfg`` is up-to-date, like
+- Ensure that all the information in ``setup.cfg`` is up-to-date, like
     supported Python versions.
 
-  - Add release date in ``docs/changelog.rst`` and integrate the output of
+- Add release date in ``docs/changelog.rst`` and integrate the output of
-    ``nox -s make_changelog``.
+  ``nox -s make_changelog``.
 
-    - Note that the ``make_changelog`` command inspects
+  - Note that the ``nox -s make_changelog`` command inspects
-      `needs changelog <https://github.com/pybind/pybind11/pulls?q=is%3Apr+is%3Aclosed+label%3A%22needs+changelog%22>`_.
+    `needs changelog <https://github.com/pybind/pybind11/pulls?q=is%3Apr+is%3Aclosed+label%3A%22needs+changelog%22>`_.
 
-    - Manually clear the ``needs changelog`` labels using the GitHub web
+  - Manually clear the ``needs changelog`` labels using the GitHub web
-      interface (very easy: start by clicking the link above).
+    interface (very easy: start by clicking the link above).
 
-  - ``git add`` and ``git commit``, ``git push``. **Ensure CI passes**. (If it
+- ``git add`` and ``git commit``, ``git push``. **Ensure CI passes**. (If it
     fails due to a known flake issue, either ignore or restart CI.)
 
 - Add a release branch if this is a new MINOR version, or update the existing

docs/upgrade.rst

@@ -8,6 +8,34 @@ to a new version. But it goes into more detail. This includes things like
 deprecated APIs and their replacements, build system changes, general code
 modernization and other useful information.
 
+.. _upgrade-guide-2.12:
+
+v2.12
+=====
+
+NumPy support has been upgraded to support the 2.x series too. The two relevant
+changes are that:
+
+* ``dtype.flags()`` is now a ``uint64`` and ``dtype.alignment()`` an
+  ``ssize_t`` (and NumPy may return an larger than integer value for
+  ``itemsize()`` in NumPy 2.x).
+
+* The long deprecated NumPy function ``PyArray_GetArrayParamsFromObject``
+  function is not available anymore.
+
+Due to NumPy changes, you may experience difficulties updating to NumPy 2.
+Please see the [NumPy 2 migration guide](https://numpy.org/devdocs/numpy_2_0_migration_guide.html) for details.
+For example, a more direct change could be that the default integer ``"int_"``
+(and ``"uint"``) is now ``ssize_t`` and not ``long`` (affects 64bit windows).
+
+If you want to only support NumPy 1.x for now and are having problems due to
+the two internal changes listed above, you can define
+``PYBIND11_NUMPY_1_ONLY`` to disable the new support for now. Make sure you
+define this on all pybind11 compile units, since it could be a source of ODR
+violations if used inconsistently. This option will be removed in the future,
+so adapting your code is highly recommended.
+
+
 .. _upgrade-guide-2.11:
 
 v2.11

include/pybind11/cast.h

@@ -357,8 +357,9 @@ public:
             value = false;
             return true;
         }
-        if (convert || (std::strcmp("numpy.bool_", Py_TYPE(src.ptr())->tp_name) == 0)) {
+        if (convert || is_numpy_bool(src)) {
-            // (allow non-implicit conversion for numpy booleans)
+            // (allow non-implicit conversion for numpy booleans), use strncmp
+            // since NumPy 1.x had an additional trailing underscore.
 
             Py_ssize_t res = -1;
             if (src.is_none()) {
@@ -390,6 +391,15 @@ public:
         return handle(src ? Py_True : Py_False).inc_ref();
     }
     PYBIND11_TYPE_CASTER(bool, const_name("bool"));
+
+private:
+    // Test if an object is a NumPy boolean (without fetching the type).
+    static inline bool is_numpy_bool(handle object) {
+        const char *type_name = Py_TYPE(object.ptr())->tp_name;
+        // Name changed to `numpy.bool` in NumPy 2, `numpy.bool_` is needed for 1.x support
+        return std::strcmp("numpy.bool", type_name) == 0
+               || std::strcmp("numpy.bool_", type_name) == 0;
+    }
 };
 
 // Helper class for UTF-{8,16,32} C++ stl strings:
@@ -696,8 +706,9 @@ public:
         return cast(*src, policy, parent);
     }
 
-    static constexpr auto name
+    static constexpr auto name = const_name("tuple[")
-        = const_name("tuple[") + concat(make_caster<Ts>::name...) + const_name("]");
+                                 + ::pybind11::detail::concat(make_caster<Ts>::name...)
+                                 + const_name("]");
 
     template <typename T>
     using cast_op_type = type;
@@ -909,10 +920,53 @@ struct is_holder_type
 template <typename base, typename deleter>
 struct is_holder_type<base, std::unique_ptr<base, deleter>> : std::true_type {};
 
+#ifdef PYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION // See PR #4888
+
+// This leads to compilation errors if a specialization is missing.
+template <typename T>
+struct handle_type_name;
+
+#else
+
 template <typename T>
 struct handle_type_name {
     static constexpr auto name = const_name<T>();
 };
+
+#endif
+
+template <>
+struct handle_type_name<object> {
+    static constexpr auto name = const_name("object");
+};
+template <>
+struct handle_type_name<list> {
+    static constexpr auto name = const_name("list");
+};
+template <>
+struct handle_type_name<dict> {
+    static constexpr auto name = const_name("dict");
+};
+template <>
+struct handle_type_name<anyset> {
+    static constexpr auto name = const_name("Union[set, frozenset]");
+};
+template <>
+struct handle_type_name<set> {
+    static constexpr auto name = const_name("set");
+};
+template <>
+struct handle_type_name<frozenset> {
+    static constexpr auto name = const_name("frozenset");
+};
+template <>
+struct handle_type_name<str> {
+    static constexpr auto name = const_name("str");
+};
+template <>
+struct handle_type_name<tuple> {
+    static constexpr auto name = const_name("tuple");
+};
 template <>
 struct handle_type_name<bool_> {
     static constexpr auto name = const_name("bool");
@@ -958,6 +1012,34 @@ struct handle_type_name<sequence> {
     static constexpr auto name = const_name("Sequence");
 };
 template <>
+struct handle_type_name<bytearray> {
+    static constexpr auto name = const_name("bytearray");
+};
+template <>
+struct handle_type_name<memoryview> {
+    static constexpr auto name = const_name("memoryview");
+};
+template <>
+struct handle_type_name<slice> {
+    static constexpr auto name = const_name("slice");
+};
+template <>
+struct handle_type_name<type> {
+    static constexpr auto name = const_name("type");
+};
+template <>
+struct handle_type_name<capsule> {
+    static constexpr auto name = const_name("capsule");
+};
+template <>
+struct handle_type_name<ellipsis> {
+    static constexpr auto name = const_name("ellipsis");
+};
+template <>
+struct handle_type_name<weakref> {
+    static constexpr auto name = const_name("weakref");
+};
+template <>
 struct handle_type_name<args> {
     static constexpr auto name = const_name("*args");
 };
@@ -965,6 +1047,30 @@ template <>
 struct handle_type_name<kwargs> {
     static constexpr auto name = const_name("**kwargs");
 };
+template <>
+struct handle_type_name<obj_attr_accessor> {
+    static constexpr auto name = const_name<obj_attr_accessor>();
+};
+template <>
+struct handle_type_name<str_attr_accessor> {
+    static constexpr auto name = const_name<str_attr_accessor>();
+};
+template <>
+struct handle_type_name<item_accessor> {
+    static constexpr auto name = const_name<item_accessor>();
+};
+template <>
+struct handle_type_name<sequence_accessor> {
+    static constexpr auto name = const_name<sequence_accessor>();
+};
+template <>
+struct handle_type_name<list_accessor> {
+    static constexpr auto name = const_name<list_accessor>();
+};
+template <>
+struct handle_type_name<tuple_accessor> {
+    static constexpr auto name = const_name<tuple_accessor>();
+};
 
 template <typename type>
 struct pyobject_caster {
@@ -1506,7 +1612,8 @@ public:
     static_assert(args_pos == -1 || args_pos == constexpr_first<argument_is_args, Args...>(),
                   "py::args cannot be specified more than once");
 
-    static constexpr auto arg_names = concat(type_descr(make_caster<Args>::name)...);
+    static constexpr auto arg_names
+        = ::pybind11::detail::concat(type_descr(make_caster<Args>::name)...);
 
     bool load_args(function_call &call) { return load_impl_sequence(call, indices{}); }
 

include/pybind11/detail/common.h

@@ -10,12 +10,12 @@
 #pragma once
 
 #define PYBIND11_VERSION_MAJOR 2
-#define PYBIND11_VERSION_MINOR 12
+#define PYBIND11_VERSION_MINOR 13
 #define PYBIND11_VERSION_PATCH 0.dev1
 
 // Similar to Python's convention: https://docs.python.org/3/c-api/apiabiversion.html
 // Additional convention: 0xD = dev
-#define PYBIND11_VERSION_HEX 0x020C00D1
+#define PYBIND11_VERSION_HEX 0x020D00D1
 
 // Define some generic pybind11 helper macros for warning management.
 //
@@ -296,6 +296,10 @@ PYBIND11_WARNING_DISABLE_MSVC(4505)
 #    undef copysign
 #endif
 
+#if defined(PYBIND11_NUMPY_1_ONLY)
+#    define PYBIND11_INTERNAL_NUMPY_1_ONLY_DETECTED
+#endif
+
 #if defined(PYPY_VERSION) && !defined(PYBIND11_SIMPLE_GIL_MANAGEMENT)
 #    define PYBIND11_SIMPLE_GIL_MANAGEMENT
 #endif

include/pybind11/detail/internals.h

@@ -68,9 +68,14 @@ inline PyObject *make_object_base_type(PyTypeObject *metaclass);
 // `Py_LIMITED_API` anyway.
 #    if PYBIND11_INTERNALS_VERSION > 4
 #        define PYBIND11_TLS_KEY_REF Py_tss_t &
-#        if defined(__GNUC__) && !defined(__INTEL_COMPILER)
+#        if defined(__clang__)
-// Clang on macOS warns due to `Py_tss_NEEDS_INIT` not specifying an initializer
+#            define PYBIND11_TLS_KEY_INIT(var)                                                    \
-// for every field.
+                _Pragma("clang diagnostic push")                                         /**/     \
+                    _Pragma("clang diagnostic ignored \"-Wmissing-field-initializers\"") /**/     \
+                    Py_tss_t var                                                                  \
+                    = Py_tss_NEEDS_INIT;                                                          \
+                _Pragma("clang diagnostic pop")
+#        elif defined(__GNUC__) && !defined(__INTEL_COMPILER)
 #            define PYBIND11_TLS_KEY_INIT(var)                                                    \
                 _Pragma("GCC diagnostic push")                                         /**/       \
                     _Pragma("GCC diagnostic ignored \"-Wmissing-field-initializers\"") /**/       \

include/pybind11/detail/type_caster_base.h

@@ -1205,13 +1205,17 @@ protected:
     static Constructor make_move_constructor(...) { return nullptr; }
 };
 
+inline std::string quote_cpp_type_name(const std::string &cpp_type_name) {
+    return cpp_type_name; // No-op for now. See PR #4888
+}
+
 PYBIND11_NOINLINE std::string type_info_description(const std::type_info &ti) {
     if (auto *type_data = get_type_info(ti)) {
         handle th((PyObject *) type_data->type);
         return th.attr("__module__").cast<std::string>() + '.'
                + th.attr("__qualname__").cast<std::string>();
     }
-    return clean_type_id(ti.name());
+    return quote_cpp_type_name(clean_type_id(ti.name()));
 }
 
 PYBIND11_NAMESPACE_END(detail)

include/pybind11/eigen/tensor.h

@@ -70,7 +70,7 @@ struct eigen_tensor_helper<Eigen::Tensor<Scalar_, NumIndices_, Options_, IndexTy
 
     template <size_t... Is>
     struct helper<index_sequence<Is...>> {
-        static constexpr auto value = concat(const_name(((void) Is, "?"))...);
+        static constexpr auto value = ::pybind11::detail::concat(const_name(((void) Is, "?"))...);
     };
 
     static constexpr auto dimensions_descriptor
@@ -104,7 +104,8 @@ struct eigen_tensor_helper<
         return get_shape() == shape;
     }
 
-    static constexpr auto dimensions_descriptor = concat(const_name<Indices>()...);
+    static constexpr auto dimensions_descriptor
+        = ::pybind11::detail::concat(const_name<Indices>()...);
 
     template <typename... Args>
     static Type *alloc(Args &&...args) {

include/pybind11/functional.h

@@ -128,7 +128,8 @@ public:
     }
 
     PYBIND11_TYPE_CASTER(type,
-                         const_name("Callable[[") + concat(make_caster<Args>::name...)
+                         const_name("Callable[[")
+                             + ::pybind11::detail::concat(make_caster<Args>::name...)
                              + const_name("], ") + make_caster<retval_type>::name
                              + const_name("]"));
 };

include/pybind11/numpy.h

@@ -29,10 +29,15 @@
 #include <utility>
 #include <vector>
 
+#if defined(PYBIND11_NUMPY_1_ONLY) && !defined(PYBIND11_INTERNAL_NUMPY_1_ONLY_DETECTED)
+#    error PYBIND11_NUMPY_1_ONLY must be defined before any pybind11 header is included.
+#endif
+
 /* This will be true on all flat address space platforms and allows us to reduce the
    whole npy_intp / ssize_t / Py_intptr_t business down to just ssize_t for all size
    and dimension types (e.g. shape, strides, indexing), instead of inflicting this
-   upon the library user. */
+   upon the library user.
+   Note that NumPy 2 now uses ssize_t for `npy_intp` to simplify this. */
 static_assert(sizeof(::pybind11::ssize_t) == sizeof(Py_intptr_t), "ssize_t != Py_intptr_t");
 static_assert(std::is_signed<Py_intptr_t>::value, "Py_intptr_t must be signed");
 // We now can reinterpret_cast between py::ssize_t and Py_intptr_t (MSVC + PyPy cares)
@@ -41,10 +46,16 @@ PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 
 PYBIND11_WARNING_DISABLE_MSVC(4127)
 
+class dtype; // Forward declaration
 class array; // Forward declaration
 
 PYBIND11_NAMESPACE_BEGIN(detail)
 
+template <>
+struct handle_type_name<dtype> {
+    static constexpr auto name = const_name("numpy.dtype");
+};
+
 template <>
 struct handle_type_name<array> {
     static constexpr auto name = const_name("numpy.ndarray");
@@ -53,7 +64,8 @@ struct handle_type_name<array> {
 template <typename type, typename SFINAE = void>
 struct npy_format_descriptor;
 
-struct PyArrayDescr_Proxy {
+/* NumPy 1 proxy (always includes legacy fields) */
+struct PyArrayDescr1_Proxy {
     PyObject_HEAD
     PyObject *typeobj;
     char kind;
@@ -68,6 +80,43 @@ struct PyArrayDescr_Proxy {
     PyObject *names;
 };
 
+#ifndef PYBIND11_NUMPY_1_ONLY
+struct PyArrayDescr_Proxy {
+    PyObject_HEAD
+    PyObject *typeobj;
+    char kind;
+    char type;
+    char byteorder;
+    char _former_flags;
+    int type_num;
+    /* Additional fields are NumPy version specific. */
+};
+#else
+/* NumPy 1.x only, we can expose all fields */
+using PyArrayDescr_Proxy = PyArrayDescr1_Proxy;
+#endif
+
+/* NumPy 2 proxy, including legacy fields */
+struct PyArrayDescr2_Proxy {
+    PyObject_HEAD
+    PyObject *typeobj;
+    char kind;
+    char type;
+    char byteorder;
+    char _former_flags;
+    int type_num;
+    std::uint64_t flags;
+    ssize_t elsize;
+    ssize_t alignment;
+    PyObject *metadata;
+    Py_hash_t hash;
+    void *reserved_null[2];
+    /* The following fields only exist if 0 <= type_num < 2056 */
+    char *subarray;
+    PyObject *fields;
+    PyObject *names;
+};
+
 struct PyArray_Proxy {
     PyObject_HEAD
     char *data;
@@ -131,6 +180,14 @@ PYBIND11_NOINLINE module_ import_numpy_core_submodule(const char *submodule_name
     object numpy_version = numpy_lib.attr("NumpyVersion")(version_string);
     int major_version = numpy_version.attr("major").cast<int>();
 
+#ifdef PYBIND11_NUMPY_1_ONLY
+    if (major_version >= 2) {
+        throw std::runtime_error(
+            "This extension was built with PYBIND11_NUMPY_1_ONLY defined, "
+            "but NumPy 2 is used in this process. For NumPy2 compatibility, "
+            "this extension needs to be rebuilt without the PYBIND11_NUMPY_1_ONLY define.");
+    }
+#endif
     /* `numpy.core` was renamed to `numpy._core` in NumPy 2.0 as it officially
         became a private module. */
     std::string numpy_core_path = major_version >= 2 ? "numpy._core" : "numpy.core";
@@ -203,6 +260,8 @@ struct npy_api {
             NPY_ULONG_, NPY_ULONGLONG_, NPY_UINT_),
     };
 
+    unsigned int PyArray_RUNTIME_VERSION_;
+
     struct PyArray_Dims {
         Py_intptr_t *ptr;
         int len;
@@ -241,6 +300,7 @@ struct npy_api {
     PyObject *(*PyArray_FromAny_)(PyObject *, PyObject *, int, int, int, PyObject *);
     int (*PyArray_DescrConverter_)(PyObject *, PyObject **);
     bool (*PyArray_EquivTypes_)(PyObject *, PyObject *);
+#ifdef PYBIND11_NUMPY_1_ONLY
     int (*PyArray_GetArrayParamsFromObject_)(PyObject *,
                                              PyObject *,
                                              unsigned char,
@@ -249,6 +309,7 @@ struct npy_api {
                                              Py_intptr_t *,
                                              PyObject **,
                                              PyObject *);
+#endif
     PyObject *(*PyArray_Squeeze_)(PyObject *);
     // Unused. Not removed because that affects ABI of the class.
     int (*PyArray_SetBaseObject_)(PyObject *, PyObject *);
@@ -266,7 +327,8 @@ private:
         API_PyArray_DescrFromScalar = 57,
         API_PyArray_FromAny = 69,
         API_PyArray_Resize = 80,
-        API_PyArray_CopyInto = 82,
+        // CopyInto was slot 82 and 50 was effectively an alias. NumPy 2 removed 82.
+        API_PyArray_CopyInto = 50,
         API_PyArray_NewCopy = 85,
         API_PyArray_NewFromDescr = 94,
         API_PyArray_DescrNewFromType = 96,
@@ -275,7 +337,9 @@ private:
         API_PyArray_View = 137,
         API_PyArray_DescrConverter = 174,
         API_PyArray_EquivTypes = 182,
+#ifdef PYBIND11_NUMPY_1_ONLY
         API_PyArray_GetArrayParamsFromObject = 278,
+#endif
         API_PyArray_SetBaseObject = 282
     };
 
@@ -290,7 +354,8 @@ private:
         npy_api api;
 #define DECL_NPY_API(Func) api.Func##_ = (decltype(api.Func##_)) api_ptr[API_##Func];
         DECL_NPY_API(PyArray_GetNDArrayCFeatureVersion);
-        if (api.PyArray_GetNDArrayCFeatureVersion_() < 0x7) {
+        api.PyArray_RUNTIME_VERSION_ = api.PyArray_GetNDArrayCFeatureVersion_();
+        if (api.PyArray_RUNTIME_VERSION_ < 0x7) {
             pybind11_fail("pybind11 numpy support requires numpy >= 1.7.0");
         }
         DECL_NPY_API(PyArray_Type);
@@ -309,7 +374,9 @@ private:
         DECL_NPY_API(PyArray_View);
         DECL_NPY_API(PyArray_DescrConverter);
         DECL_NPY_API(PyArray_EquivTypes);
+#ifdef PYBIND11_NUMPY_1_ONLY
         DECL_NPY_API(PyArray_GetArrayParamsFromObject);
+#endif
         DECL_NPY_API(PyArray_SetBaseObject);
 
 #undef DECL_NPY_API
@@ -331,6 +398,14 @@ inline const PyArrayDescr_Proxy *array_descriptor_proxy(const PyObject *ptr) {
     return reinterpret_cast<const PyArrayDescr_Proxy *>(ptr);
 }
 
+inline const PyArrayDescr1_Proxy *array_descriptor1_proxy(const PyObject *ptr) {
+    return reinterpret_cast<const PyArrayDescr1_Proxy *>(ptr);
+}
+
+inline const PyArrayDescr2_Proxy *array_descriptor2_proxy(const PyObject *ptr) {
+    return reinterpret_cast<const PyArrayDescr2_Proxy *>(ptr);
+}
+
 inline bool check_flags(const void *ptr, int flag) {
     return (flag == (array_proxy(ptr)->flags & flag));
 }
@@ -371,7 +446,7 @@ struct array_info<std::array<T, N>> {
     }
 
     static constexpr auto extents = const_name<array_info<T>::is_array>(
-        concat(const_name<N>(), array_info<T>::extents), const_name<N>());
+        ::pybind11::detail::concat(const_name<N>(), array_info<T>::extents), const_name<N>());
 };
 // For numpy we have special handling for arrays of characters, so we don't include
 // the size in the array extents.
@@ -610,10 +685,32 @@ public:
     }
 
     /// Size of the data type in bytes.
+#ifdef PYBIND11_NUMPY_1_ONLY
     ssize_t itemsize() const { return detail::array_descriptor_proxy(m_ptr)->elsize; }
+#else
+    ssize_t itemsize() const {
+        if (detail::npy_api::get().PyArray_RUNTIME_VERSION_ < 0x12) {
+            return detail::array_descriptor1_proxy(m_ptr)->elsize;
+        }
+        return detail::array_descriptor2_proxy(m_ptr)->elsize;
+    }
+#endif
 
     /// Returns true for structured data types.
+#ifdef PYBIND11_NUMPY_1_ONLY
     bool has_fields() const { return detail::array_descriptor_proxy(m_ptr)->names != nullptr; }
+#else
+    bool has_fields() const {
+        if (detail::npy_api::get().PyArray_RUNTIME_VERSION_ < 0x12) {
+            return detail::array_descriptor1_proxy(m_ptr)->names != nullptr;
+        }
+        const auto *proxy = detail::array_descriptor2_proxy(m_ptr);
+        if (proxy->type_num < 0 || proxy->type_num >= 2056) {
+            return false;
+        }
+        return proxy->names != nullptr;
+    }
+#endif
 
     /// Single-character code for dtype's kind.
     /// For example, floating point types are 'f' and integral types are 'i'.
@@ -639,11 +736,29 @@ public:
     /// Single character for byteorder
     char byteorder() const { return detail::array_descriptor_proxy(m_ptr)->byteorder; }
 
-    /// Alignment of the data type
+/// Alignment of the data type
+#ifdef PYBIND11_NUMPY_1_ONLY
     int alignment() const { return detail::array_descriptor_proxy(m_ptr)->alignment; }
+#else
+    ssize_t alignment() const {
+        if (detail::npy_api::get().PyArray_RUNTIME_VERSION_ < 0x12) {
+            return detail::array_descriptor1_proxy(m_ptr)->alignment;
+        }
+        return detail::array_descriptor2_proxy(m_ptr)->alignment;
+    }
+#endif
 
-    /// Flags for the array descriptor
+/// Flags for the array descriptor
+#ifdef PYBIND11_NUMPY_1_ONLY
     char flags() const { return detail::array_descriptor_proxy(m_ptr)->flags; }
+#else
+    std::uint64_t flags() const {
+        if (detail::npy_api::get().PyArray_RUNTIME_VERSION_ < 0x12) {
+            return (unsigned char) detail::array_descriptor1_proxy(m_ptr)->flags;
+        }
+        return detail::array_descriptor2_proxy(m_ptr)->flags;
+    }
+#endif
 
 private:
     static object &_dtype_from_pep3118() {
@@ -810,9 +925,7 @@ public:
     }
 
     /// Byte size of a single element
-    ssize_t itemsize() const {
+    ssize_t itemsize() const { return dtype().itemsize(); }
-        return detail::array_descriptor_proxy(detail::array_proxy(m_ptr)->descr)->elsize;
-    }
 
     /// Total number of bytes
     ssize_t nbytes() const { return size() * itemsize(); }

include/pybind11/pybind11.h

@@ -493,9 +493,7 @@ protected:
                     signature += rec->scope.attr("__module__").cast<std::string>() + "."
                                  + rec->scope.attr("__qualname__").cast<std::string>();
                 } else {
-                    std::string tname(t->name());
+                    signature += detail::quote_cpp_type_name(detail::clean_type_id(t->name()));
-                    detail::clean_type_id(tname);
-                    signature += tname;
                 }
             } else {
                 signature += c;
@@ -1193,6 +1191,15 @@ protected:
     }
 };
 
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+template <>
+struct handle_type_name<cpp_function> {
+    static constexpr auto name = const_name("Callable");
+};
+
+PYBIND11_NAMESPACE_END(detail)
+
 /// Wrapper for Python extension modules
 class module_ : public object {
 public:
@@ -1320,6 +1327,15 @@ public:
     }
 };
 
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+template <>
+struct handle_type_name<module_> {
+    static constexpr auto name = const_name("module");
+};
+
+PYBIND11_NAMESPACE_END(detail)
+
 // When inside a namespace (or anywhere as long as it's not the first item on a line),
 // C++20 allows "module" to be used. This is provided for backward compatibility, and for
 // simplicity, if someone wants to use py::module for example, that is perfectly safe.
@@ -2871,6 +2887,11 @@ public:
 
 PYBIND11_NAMESPACE_BEGIN(detail)
 
+template <>
+struct handle_type_name<exception<void>> {
+    static constexpr auto name = const_name("Exception");
+};
+
 // Helper function for register_exception and register_local_exception
 template <typename CppException>
 exception<CppException> &

include/pybind11/pytypes.h

@@ -59,6 +59,7 @@ struct sequence_item;
 struct list_item;
 struct tuple_item;
 } // namespace accessor_policies
+// PLEASE KEEP handle_type_name SPECIALIZATIONS IN SYNC.
 using obj_attr_accessor = accessor<accessor_policies::obj_attr>;
 using str_attr_accessor = accessor<accessor_policies::str_attr>;
 using item_accessor = accessor<accessor_policies::generic_item>;

include/pybind11/stl.h

@@ -424,7 +424,8 @@ struct variant_caster<V<Ts...>> {
 
     using Type = V<Ts...>;
     PYBIND11_TYPE_CASTER(Type,
-                         const_name("Union[") + detail::concat(make_caster<Ts>::name...)
+                         const_name("Union[")
+                             + ::pybind11::detail::concat(make_caster<Ts>::name...)
                              + const_name("]"));
 };
 

include/pybind11/typing.h

@@ -69,8 +69,9 @@ PYBIND11_NAMESPACE_BEGIN(detail)
 
 template <typename... Types>
 struct handle_type_name<typing::Tuple<Types...>> {
-    static constexpr auto name
+    static constexpr auto name = const_name("tuple[")
-        = const_name("tuple[") + concat(make_caster<Types>::name...) + const_name("]");
+                                 + ::pybind11::detail::concat(make_caster<Types>::name...)
+                                 + const_name("]");
 };
 
 template <>
@@ -79,6 +80,13 @@ struct handle_type_name<typing::Tuple<>> {
     static constexpr auto name = const_name("tuple[()]");
 };
 
+template <typename T>
+struct handle_type_name<typing::Tuple<T, ellipsis>> {
+    // PEP 484 specifies this syntax for a variable-length tuple
+    static constexpr auto name
+        = const_name("tuple[") + make_caster<T>::name + const_name(", ...]");
+};
+
 template <typename K, typename V>
 struct handle_type_name<typing::Dict<K, V>> {
     static constexpr auto name = const_name("dict[") + make_caster<K>::name + const_name(", ")
@@ -108,9 +116,9 @@ struct handle_type_name<typing::Iterator<T>> {
 template <typename Return, typename... Args>
 struct handle_type_name<typing::Callable<Return(Args...)>> {
     using retval_type = conditional_t<std::is_same<Return, void>::value, void_type, Return>;
-    static constexpr auto name = const_name("Callable[[") + concat(make_caster<Args>::name...)
+    static constexpr auto name
-                                 + const_name("], ") + make_caster<retval_type>::name
+        = const_name("Callable[[") + ::pybind11::detail::concat(make_caster<Args>::name...)
-                                 + const_name("]");
+          + const_name("], ") + make_caster<retval_type>::name + const_name("]");
 };
 
 PYBIND11_NAMESPACE_END(detail)

pybind11/_version.py

@@ -8,5 +8,5 @@ def _to_int(s: str) -> Union[int, str]:
         return s
 
 
-__version__ = "2.12.0.dev1"
+__version__ = "2.13.0.dev1"
 version_info = tuple(_to_int(s) for s in __version__.split("."))

tests/CMakeLists.txt

@@ -557,11 +557,15 @@ set(PYBIND11_TEST_PREFIX_COMMAND
     ""
     CACHE STRING "Put this before pytest, use for checkers and such")
 
+set(PYBIND11_PYTEST_ARGS
+    ""
+    CACHE STRING "Extra arguments for pytest")
+
 # A single command to compile and run the tests
 add_custom_target(
   pytest
   COMMAND ${PYBIND11_TEST_PREFIX_COMMAND} ${PYTHON_EXECUTABLE} -m pytest
-          ${PYBIND11_ABS_PYTEST_FILES}
+          ${PYBIND11_ABS_PYTEST_FILES} ${PYBIND11_PYTEST_ARGS}
   DEPENDS ${test_targets}
   WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}"
   USES_TERMINAL)

tests/conftest.py

@@ -218,4 +218,5 @@ def pytest_report_header(config):
         f" {pybind11_tests.cpp_std}"
         f" {pybind11_tests.PYBIND11_INTERNALS_ID}"
         f" PYBIND11_SIMPLE_GIL_MANAGEMENT={pybind11_tests.PYBIND11_SIMPLE_GIL_MANAGEMENT}"
+        f" PYBIND11_NUMPY_1_ONLY={pybind11_tests.PYBIND11_NUMPY_1_ONLY}"
     )

tests/pybind11_tests.cpp

@@ -80,10 +80,10 @@ PYBIND11_MODULE(pybind11_tests, m) {
 
     // Intentionally kept minimal to not create a maintenance chore
     // ("just enough" to be conclusive).
-#if defined(_MSC_FULL_VER)
+#if defined(__VERSION__)
-    m.attr("compiler_info") = "MSVC " PYBIND11_TOSTRING(_MSC_FULL_VER);
-#elif defined(__VERSION__)
     m.attr("compiler_info") = __VERSION__;
+#elif defined(_MSC_FULL_VER)
+    m.attr("compiler_info") = "MSVC " PYBIND11_TOSTRING(_MSC_FULL_VER);
 #else
     m.attr("compiler_info") = py::none();
 #endif
@@ -95,6 +95,12 @@ PYBIND11_MODULE(pybind11_tests, m) {
 #else
         false;
 #endif
+    m.attr("PYBIND11_NUMPY_1_ONLY") =
+#if defined(PYBIND11_NUMPY_1_ONLY)
+        true;
+#else
+        false;
+#endif
 
     bind_ConstructorStats(m);
 

tests/test_constants_and_functions.cpp

@@ -54,7 +54,11 @@ int f2(int x) noexcept(true) { return x + 2; }
 int f3(int x) noexcept(false) { return x + 3; }
 PYBIND11_WARNING_PUSH
 PYBIND11_WARNING_DISABLE_GCC("-Wdeprecated")
+#if defined(__clang_major__) && __clang_major__ >= 5
+PYBIND11_WARNING_DISABLE_CLANG("-Wdeprecated-dynamic-exception-spec")
+#else
 PYBIND11_WARNING_DISABLE_CLANG("-Wdeprecated")
+#endif
 // NOLINTNEXTLINE(modernize-use-noexcept)
 int f4(int x) throw() { return x + 4; } // Deprecated equivalent to noexcept(true)
 PYBIND11_WARNING_POP

tests/test_custom_type_casters.cpp

@@ -134,6 +134,16 @@ struct type_caster<other_lib::MyType> : public other_lib::my_caster {};
 } // namespace detail
 } // namespace PYBIND11_NAMESPACE
 
+// This simply is required to compile
+namespace ADL_issue {
+template <typename OutStringType = std::string, typename... Args>
+OutStringType concat(Args &&...) {
+    return OutStringType();
+}
+
+struct test {};
+} // namespace ADL_issue
+
 TEST_SUBMODULE(custom_type_casters, m) {
     // test_custom_type_casters
 
@@ -206,4 +216,6 @@ TEST_SUBMODULE(custom_type_casters, m) {
           py::return_value_policy::reference);
 
     m.def("other_lib_type", [](other_lib::MyType x) { return x; });
+
+    m.def("_adl_issue", [](const ADL_issue::test &) {});
 }

tests/test_eigen_matrix.py

@@ -608,7 +608,9 @@ def test_both_ref_mutators():
 def test_nocopy_wrapper():
     # get_elem requires a column-contiguous matrix reference, but should be
     # callable with other types of matrix (via copying):
-    int_matrix_colmajor = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]], order="F")
+    int_matrix_colmajor = np.array(
+        [[1, 2, 3], [4, 5, 6], [7, 8, 9]], dtype="l", order="F"
+    )
     dbl_matrix_colmajor = np.array(
         int_matrix_colmajor, dtype="double", order="F", copy=True
     )

tests/test_exceptions.cpp

@@ -382,4 +382,7 @@ TEST_SUBMODULE(exceptions, m) {
         // function returns None instead of int, should give a useful error message
         fn().cast<int>();
     });
+
+    // m.def("pass_exception_void", [](const py::exception<void>&) {}); // Does not compile.
+    m.def("return_exception_void", []() { return py::exception<void>(); });
 }

tests/test_exceptions.py

@@ -4,7 +4,7 @@ import pytest
 
 import env
 import pybind11_cross_module_tests as cm
-import pybind11_tests  # noqa: F401
+import pybind11_tests
 from pybind11_tests import exceptions as m
 
 
@@ -248,6 +248,11 @@ def test_nested_throws(capture):
     assert str(excinfo.value) == "this is a helper-defined translated exception"
 
 
+# TODO: Investigate this crash, see pybind/pybind11#5062 for background
+@pytest.mark.skipif(
+    sys.platform.startswith("win32") and "Clang" in pybind11_tests.compiler_info,
+    reason="Started segfaulting February 2024",
+)
 def test_throw_nested_exception():
     with pytest.raises(RuntimeError) as excinfo:
         m.throw_nested_exception()
@@ -419,3 +424,9 @@ def test_fn_cast_int_exception():
     assert str(excinfo.value).startswith(
         "Unable to cast Python instance of type <class 'NoneType'> to C++ type"
     )
+
+
+def test_return_exception_void():
+    with pytest.raises(TypeError) as excinfo:
+        m.return_exception_void()
+    assert "Exception" in str(excinfo.value)

tests/test_numpy_array.py

@@ -536,7 +536,12 @@ def test_format_descriptors_for_floating_point_types(test_func):
 @pytest.mark.parametrize("contiguity", [None, "C", "F"])
 @pytest.mark.parametrize("noconvert", [False, True])
 @pytest.mark.filterwarnings(
-    "ignore:Casting complex values to real discards the imaginary part:numpy.ComplexWarning"
+    "ignore:Casting complex values to real discards the imaginary part:"
+    + (
+        "numpy.exceptions.ComplexWarning"
+        if hasattr(np, "exceptions")
+        else "numpy.ComplexWarning"
+    )
 )
 def test_argument_conversions(forcecast, contiguity, noconvert):
     function_name = "accept_double"
@@ -583,7 +588,8 @@ def test_argument_conversions(forcecast, contiguity, noconvert):
 def test_dtype_refcount_leak():
     from sys import getrefcount
 
-    dtype = np.dtype(np.float_)
+    # Was np.float_ but that alias for float64 was removed in NumPy 2.
+    dtype = np.dtype(np.float64)
     a = np.array([1], dtype=dtype)
     before = getrefcount(dtype)
     m.ndim(a)

tests/test_numpy_dtypes.cpp

@@ -405,10 +405,35 @@ TEST_SUBMODULE(numpy_dtypes, m) {
     });
 
     // test_dtype
+    // Below we use `L` for unsigned long as unfortunately the only name that
+    // works reliably on Both NumPy 2.x and old NumPy 1.x.
     std::vector<const char *> dtype_names{
-        "byte",    "short",   "intc",        "int_",  "longlong",   "ubyte",       "ushort",
+        "byte",
-        "uintc",   "uint",    "ulonglong",   "half",  "single",     "double",      "longdouble",
+        "short",
-        "csingle", "cdouble", "clongdouble", "bool_", "datetime64", "timedelta64", "object_"};
+        "intc",
+        "long",
+        "longlong",
+        "ubyte",
+        "ushort",
+        "uintc",
+        "L",
+        "ulonglong",
+        "half",
+        "single",
+        "double",
+        "longdouble",
+        "csingle",
+        "cdouble",
+        "clongdouble",
+        "bool_",
+        "datetime64",
+        "timedelta64",
+        "object_",
+        // platform dependent aliases (int_ and uint are also NumPy version dependent on windows)
+        "int_",
+        "uint",
+        "intp",
+        "uintp"};
 
     m.def("print_dtypes", []() {
         py::list l;

tests/test_numpy_dtypes.py

@@ -3,6 +3,7 @@ import re
 import pytest
 
 import env  # noqa: F401
+from pybind11_tests import PYBIND11_NUMPY_1_ONLY
 from pybind11_tests import numpy_dtypes as m
 
 np = pytest.importorskip("numpy")
@@ -172,13 +173,20 @@ def test_dtype(simple_dtype):
         np.zeros(1, m.trailing_padding_dtype())
     )
 
-    expected_chars = "bhilqBHILQefdgFDG?MmO"
+    expected_chars = list("bhilqBHILQefdgFDG?MmO")
-    assert m.test_dtype_kind() == list("iiiiiuuuuuffffcccbMmO")
+    # Note that int_ and uint size and mapping is NumPy version dependent:
+    expected_chars += [np.dtype(_).char for _ in ("int_", "uint", "intp", "uintp")]
+    assert m.test_dtype_kind() == list("iiiiiuuuuuffffcccbMmOiuiu")
     assert m.test_dtype_char_() == list(expected_chars)
     assert m.test_dtype_num() == [np.dtype(ch).num for ch in expected_chars]
     assert m.test_dtype_byteorder() == [np.dtype(ch).byteorder for ch in expected_chars]
     assert m.test_dtype_alignment() == [np.dtype(ch).alignment for ch in expected_chars]
-    assert m.test_dtype_flags() == [chr(np.dtype(ch).flags) for ch in expected_chars]
+    if not PYBIND11_NUMPY_1_ONLY:
+        assert m.test_dtype_flags() == [np.dtype(ch).flags for ch in expected_chars]
+    else:
+        assert m.test_dtype_flags() == [
+            chr(np.dtype(ch).flags) for ch in expected_chars
+        ]
 
 
 def test_recarray(simple_dtype, packed_dtype):

tests/test_pytypes.cpp

@@ -41,6 +41,15 @@ class float_ : public py::object {
 };
 } // namespace external
 
+namespace pybind11 {
+namespace detail {
+template <>
+struct handle_type_name<external::float_> {
+    static constexpr auto name = const_name("float");
+};
+} // namespace detail
+} // namespace pybind11
+
 namespace implicit_conversion_from_0_to_handle {
 // Uncomment to trigger compiler error. Note: Before PR #4008 this used to compile successfully.
 // void expected_to_trigger_compiler_error() { py::handle(0); }
@@ -825,6 +834,8 @@ TEST_SUBMODULE(pytypes, m) {
 
     m.def("annotate_tuple_float_str", [](const py::typing::Tuple<py::float_, py::str> &) {});
     m.def("annotate_tuple_empty", [](const py::typing::Tuple<> &) {});
+    m.def("annotate_tuple_variable_length",
+          [](const py::typing::Tuple<py::float_, py::ellipsis> &) {});
     m.def("annotate_dict_str_int", [](const py::typing::Dict<py::str, int> &) {});
     m.def("annotate_list_int", [](const py::typing::List<int> &) {});
     m.def("annotate_set_str", [](const py::typing::Set<std::string> &) {});

tests/test_pytypes.py

@@ -121,7 +121,7 @@ def test_set(capture, doc):
     assert m.anyset_contains({"foo"}, "foo")
 
     assert doc(m.get_set) == "get_set() -> set"
-    assert doc(m.print_anyset) == "print_anyset(arg0: anyset) -> None"
+    assert doc(m.print_anyset) == "print_anyset(arg0: Union[set, frozenset]) -> None"
 
 
 def test_frozenset(capture, doc):
@@ -911,6 +911,13 @@ def test_tuple_empty_annotations(doc):
     )
 
 
+def test_tuple_variable_length_annotations(doc):
+    assert (
+        doc(m.annotate_tuple_variable_length)
+        == "annotate_tuple_variable_length(arg0: tuple[float, ...]) -> None"
+    )
+
+
 def test_dict_annotations(doc):
     assert (
         doc(m.annotate_dict_str_int)

tools/make_changelog.py

@@ -67,9 +67,11 @@ for issue in issues:
 for cat, msgs in cats.items():
     if msgs:
         desc = cats_descr[cat]
-        print(f"[bold]{desc}:\n" if desc else "")
+        print(f"[bold]{desc}:" if desc else f".. {cat}")
+        print()
         for msg in msgs:
             print(Syntax(msg, "rst", theme="ansi_light", word_wrap=True))
+            print()
         print()
 
 if missing:

tools/pybind11Common.cmake

@@ -173,12 +173,16 @@ endif()
 # Check to see which Python mode we are in, new, old, or no python
 if(PYBIND11_NOPYTHON)
   set(_pybind11_nopython ON)
+  # We won't use new FindPython if PYBIND11_FINDPYTHON is defined and falselike
+  # Otherwise, we use if FindPythonLibs is missing or if FindPython was already used
 elseif(
-  _pybind11_missing_old_python STREQUAL "NEW"
+  (NOT DEFINED PYBIND11_FINDPYTHON OR PYBIND11_FINDPYTHON)
-  OR PYBIND11_FINDPYTHON
+  AND (_pybind11_missing_old_python STREQUAL "NEW"
-  OR Python_FOUND
+       OR PYBIND11_FINDPYTHON
-  OR Python2_FOUND
+       OR Python_FOUND
-  OR Python3_FOUND)
+       OR Python3_FOUND
+      ))
+
   # New mode
   include("${CMAKE_CURRENT_LIST_DIR}/pybind11NewTools.cmake")