* Equivalent of https://github.com/google/clif/commit/5718e4d0807fd3b6a8187dde140069120b81ecef

* Resolve clang-tidy errors.

* Moving test_PPCCInit() first changes the behavior!

* Resolve new Clang dev C++11 errors:

```
The CXX compiler identification is Clang 17.0.0
```

```
pytypes.h:1615:23: error: identifier '_s' preceded by whitespace in a literal operator declaration is deprecated [-Werror,-Wdeprecated-literal-operator]
```

```
cast.h:1380:26: error: identifier '_a' preceded by whitespace in a literal operator declaration is deprecated [-Werror,-Wdeprecated-literal-operator]
```

* Resolve gcc 4.8.5 error:

```
pytypes.h:1615:12: error: missing space between '""' and suffix identifier
```

* Specifically exclude `__clang__`

* Snapshot of debugging code (does NOT pass pre-commit checks).

* Revert "Snapshot of debugging code (does NOT pass pre-commit checks)."

This reverts commit 1d4f9ff2632b32ddcb0dc7ecd0ab7a4ce4c15a4e.

* [ci skip] Order Dependence Demo

* Revert "[ci skip] Order Dependence Demo"

This reverts commit d37b5409d4e5b835620ccbb321a4e1ba89af315c.

* One way to deal with the order dependency issue. This is not the best way, more like a proof of concept.

* Move test_PC() first again.

* Add `all_type_info_add_base_most_derived_first()`, use in `all_type_info_populate()`

* Revert "One way to deal with the order dependency issue. This is not the best way, more like a proof of concept."

This reverts commit eb09c6c1b978208ceee40f05bbe75491b6ff8ad6.

* clang-tidy fixes (automatic)

* Add `is_redundant_value_and_holder()` and use to avoid forcing `__init__` overrides when they are not needed.

* Streamline implementation and avoid unsafe `reinterpret_cast<instance *>()` introduced with PR #2152

The `reinterpret_cast<instance *>(self)` is unsafe if `__new__` is mocked,
which was actually found in the wild: the mock returned `None` for `self`.
This was inconsequential because `inst` is currently cast straight back to
`PyObject *` to compute `all_type_info()`, which is empty if `self` is not
a pybind11 `instance`, and then `inst` is never dereferenced. However, the
unsafe detour through `instance *` is easily avoided and the updated
implementation is less prone to accidents while debugging or refactoring.

* Fix actual undefined behavior exposed by previous changes.

It turns out the previous commit message is incorrect, the `inst` pointer is actually dereferenced, in the `value_and_holder` ctor here:

https://github.com/pybind/pybind11/blob/f3e0602802c7840992c97f4960515777cad6a5c7/include/pybind11/detail/type_caster_base.h#L262-L263

```
259     // Main constructor for a found value/holder:
260     value_and_holder(instance *i, const detail::type_info *type, size_t vpos, size_t index)
261         : inst{i}, index{index}, type{type},
262           vh{inst->simple_layout ? inst->simple_value_holder
263                                  : &inst->nonsimple.values_and_holders[vpos]} {}
```

* Add test_mock_new()

* Experiment: specify indirect bases

* Revert "Experiment: specify indirect bases"

This reverts commit 4f90d85f9fc15290d6be54d5ae9417bd131b84d9.

* Add `all_type_info_check_for_divergence()` and some tests.

* Call `all_type_info_check_for_divergence()` also from `type_caster_generic::load_impl<>`

* Resolve clang-tidy error:

```
include/pybind11/detail/type_caster_base.h:795:21: error: the 'empty' method should be used to check for emptiness instead of 'size' [readability-container-size-empty,-warnings-as-errors]
                if (matching_bases.size() != 0) {
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~
                    !matching_bases.empty()
```

* Revert "Resolve clang-tidy error:"

This reverts commit df27188dc6d6cf333145755543f56b2f6657aa5e.

* Revert "Call `all_type_info_check_for_divergence()` also from `type_caster_generic::load_impl<>`"

This reverts commit 5f5fd6a68e3cff1726628f6dea8e1c0754636a23.

* Revert "Add `all_type_info_check_for_divergence()` and some tests."

This reverts commit 0a9599f775bfd3ca196c5e23a3fcf2890cbf6e82.

https://github.com/pybind/pybind11/pull/4916/files#r1387035547

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>
Co-authored-by: Ralf W. Grosse-Kunstleve <rwgk@google.com>

updates:
- [github.com/pre-commit/mirrors-clang-format: v17.0.3 → v17.0.4](https://github.com/pre-commit/mirrors-clang-format/compare/v17.0.3...v17.0.4)
- [github.com/astral-sh/ruff-pre-commit: v0.1.2 → v0.1.4](https://github.com/astral-sh/ruff-pre-commit/compare/v0.1.2...v0.1.4

)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

* Roundtrip through unique pointer with custom deleter.

Currently failing.

* Ensure the custom deleter is copied back to the unique pointer.

Feels like there's still a gap around the raw pointer flavour, but this at least
makes the unit test of the previous commit succeed.

* Add deleter roundtrip for const atyp.

Currently failing, custom deleter is lost.

* Fix storing deleter for const unique ptr.

Unit test from the previous commit passes.

* Remove SFINEA deleter assignment.

At the construction of the smart holder, it is either a del_fun, or a default constructed deleter, so this complexity is unnecessary.

* Clang format.

* Fixes for ci.

Clang 3.6 requires the extra constructors in the custom_deleter.

* fix(smart_holder): Loosen requirement on deleter to be default constructible.

And some other PR feedback.

* fix(smart_holder): Custom deleter in unit tests traces constructions.

* fix(smart_holder): Use pybind11_fail instead of assert.

* fix(smart_holder): Add unit tests for the default constructible deleter.

* fix(smart_holder): Use regex matching for deleter constructors in unit tests.

Ensures `std::default_delete<T>` is used to look up the deleter for a type instead of `delete` directly.

* Use PyCode API

* style: pre-commit fixes

* Free locals

* Fix PY_VERSION_HEX check

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

[smart_holder] type_caster_odr_guard MSVC 193732825 C++17 windows-2022 is failing for unknown reasons. (#4918)

* MSVC 193732825 C++17 windows-2022 is failing for unknown reasons.

* Bug fix: Need to test `_MSC_FULL_VER` (not `_MSC_VER`).

* Store `std::function<void (void *)>` del_fun; in `guarded_delete`

* Specialize the simple common case.

Using a `union` is complicated: https://en.cppreference.com/w/cpp/language/union

> If members of a union are classes with user-defined constructors and destructors, to switch the active member, explicit destructor and placement new are generally needed:

Using `std::variant` increases compile-time overhead.

It is currently unclear how much these effects matter in practice: optimization left for later.

* Add one test case (more later).

* Add `const` to resolve clang-tidy error.

```
-- The CXX compiler identification is Clang 15.0.7

/usr/bin/cmake -E __run_co_compile --tidy="/usr/bin/clang-tidy;--use-color;--warnings-as-errors=*;--extra-arg-before=--driver-mode=g++" --source=/__w/pybind11/pybind11/tests/test_class_sh_inheritance.cpp -- /usr/bin/c++ -DPYBIND11_ENABLE_TYPE_CASTER_ODR_GUARD_IF_AVAILABLE -DPYBIND11_TEST_EIGEN -Dpybind11_tests_EXPORTS -I/__w/pybind11/pybind11/include -isystem /usr/include/python3.9 -isystem /__w/pybind11/pybind11/build/_deps/eigen-src -Os -DNDEBUG -fPIC -fvisibility=hidden -Wall -Wextra -Wconversion -Wcast-qual -Wdeprecated -Wundef -Wnon-virtual-dtor -flto=thin -std=c++17 -o CMakeFiles/pybind11_tests.dir/test_class_sh_inheritance.cpp.o -c /__w/pybind11/pybind11/tests/test_class_sh_inheritance.cpp
/__w/pybind11/pybind11/tests/pure_cpp/smart_holder_poc_test.cpp:264:30: error: pointer parameter 'raw_ptr' can be pointer to const [readability-non-const-parameter,-warnings-as-errors]
        new int(19), [](int *raw_ptr) { delete raw_ptr; });
                             ^
                        const
```

* Introduce `struct custom_deleter` to ensure the deleter is moved as desired (the lambda function only captures a reference, which can become dangling).

* Resolve helpful clang-tidy errors.

```
/usr/bin/cmake -E __run_co_compile --tidy="/usr/bin/clang-tidy;--use-color;--warnings-as-errors=*;--extra-arg-before=--driver-mode=g++" --source=/__w/pybind11/pybind11/tests/test_class.cpp -- /usr/bin/c++ -DPYBIND11_ENABLE_TYPE_CASTER_ODR_GUARD_IF_AVAILABLE -DPYBIND11_TEST_EIGEN -Dpybind11_tests_EXPORTS -I/__w/pybind11/pybind11/include -isystem /usr/include/python3.9 -isystem /__w/pybind11/pybind11/build/_deps/eigen-src -Os -DNDEBUG -fPIC -fvisibility=hidden -Wall -Wextra -Wconversion -Wcast-qual -Wdeprecated -Wundef -Wnon-virtual-dtor -flto=thin -std=c++17 -o CMakeFiles/pybind11_tests.dir/test_class.cpp.o -c /__w/pybind11/pybind11/tests/test_class.cpp
/__w/pybind11/pybind11/include/pybind11/detail/smart_holder_poc.h:114:5: error: single-argument constructors must be marked explicit to avoid unintentional implicit conversions [google-explicit-constructor,-warnings-as-errors]
    custom_deleter(D &&deleter) : deleter{std::move(deleter)} {}
    ^
    explicit
/__w/pybind11/pybind11/include/pybind11/detail/smart_holder_poc.h:120:76: error: forwarding reference passed to std::move(), which may unexpectedly cause lvalues to be moved; use std::forward() instead [bugprone-move-forwarding-reference,-warnings-as-errors]
    return guarded_delete(std::function<void(void *)>(custom_deleter<T, D>(std::move(uqp_del))),
                                                                           ^~~~~~~~~
                                                                           std::forward<D>
```

* Workaround for gcc 4.8.5, clang 3.6

* Transfer reduced test here.

Reduced from a PyCLIF use case in the wild by @wangxf123456 (internal change cl/565476030).

* Add missing include (clangd Include Cleaner)

* Change `std::move` to `std::forward` as suggested by @iwanders.

* Add missing includes (clangd Include Cleaner)

* Use new `PYBIND11_TESTS_PURE_CPP_SMART_HOLDER_POC_TEST_CPP` to exclude `smart_holder::as_unique_ptr` method from production code.

* Systematically add `PYBIND11_TESTS_PURE_CPP_SMART_HOLDER_POC_TEST_CPP` to mark code that is not used from production code. Add comment to explain.

* Very simple experiment related to https://github.com/pybind/pybind11/pull/4850#issuecomment-1789780676

Does the `PYBIND11_TESTS_PURE_CPP_SMART_HOLDER_POC_TEST_CPP` define have anything to do with it?

* Revert "Very simple experiment related to https://github.com/pybind/pybind11/pull/4850#issuecomment-1789780676"

This reverts commit fe59369f408d354edef16e3d40e2f90d9c2a9ba8.

Add 3.12 to the default `Python_ADDITIONAL_VERSIONS`.

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

```
mypy.....................................................................Failed
- hook id: mypy
- exit code: 1

ubench/holder_comparison.py:12: error: Unused "type: ignore" comment, use narrower [import-not-found] instead of [import] code  [unused-ignore]
```

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

* [minor] Add a missing space

Add a missing space to error message

* Add space after period, always add newline.

According to https://docs.python.org/3.13/whatsnew/3.13.html:

Add PyThreadState_GetUnchecked() function: similar to
PyThreadState_Get(), but don't kill the process with a fatal error if
it is NULL. The caller is responsible to check if the result is
NULL. Previously, the function was private and known as
_PyThreadState_UncheckedGet().

This is to ensure that `Py_DECREF()` is not called after the Python interpreter was finalized already:

https://github.com/pybind/pybind11/blob/3414c56b6c7c521d868c9a137ca2ace2e26b5b2e/include/pybind11/gil_safe_call_once.h#L19

* Workaround NVCC parse failure in `cast_op`

There is a bug in some CUDA versions (observed in CUDA 12.1 and 11.7 w/ GCC 12.2),
that makes `cast_op` fail to compile:
  `cast.h:45:120: error: expected template-name before ‘<’ token`

Defining the nested type as an alias and using it allows this to work
without any change in semantics.

Fixes #4606

* style: pre-commit fixes

* Add comments to result_t referencing PR

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

* Update pytest (which removes their dependency on py)

The py library through 1.11.0 for Python allows remote attackers to conduct a ReDoS (Regular expression Denial of Service) attack via a Subversion repository with crafted info data, because the InfoSvnCommand argument is mishandled.

The particular codepath in question is the regular expression at py._path.svnurl.InfoSvnCommand.lspattern and is only relevant when dealing with subversion (svn) projects. Notably the codepath is not used in the popular pytest project. The developers of the pytest package have released version 7.2.0 which removes their dependency on py. Users of pytest seeing alerts relating to this advisory may update to version 7.2.0 of pytest to resolve this issue. See https://github.com/pytest-dev/py/issues/287#issuecomment-1290407715 for additional context.

* Added conditions so that we keep using 7.0.0 on python 3.6

* LazyInitializeAtLeastOnceDestroyNever v1

* Go back to using `union` as originally suggested by jbms@. The trick (also suggested by jbms@) is to add empty ctor + dtor.

* Revert "Go back to using `union` as originally suggested by jbms@. The trick (also suggested by jbms@) is to add empty ctor + dtor."

This reverts commit e7b8c4f0fcd72191e88d1c17abf5da08fe3a9c6f.

* Remove `#include <stdalign.h>`

* `include\pybind11/numpy.h(24,10): fatal error C1083: Cannot open include file: 'stdalign.h': No such file or directory`

* @tkoeppe wrote: this is a C interop header (and we're not writing C)

* Suppress gcc 4.8.5 (CentOS 7) warning.

```
include/pybind11/eigen/../numpy.h:63:53: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
         return *reinterpret_cast<T *>(value_storage_);
                                                     ^
```

* Replace comments:

Document PRECONDITION.

Adopt comment suggested by @tkoeppe: https://github.com/pybind/pybind11/pull/4877#discussion_r1350356093

* Adopt suggestion by @tkoeppe:

* https://github.com/pybind/pybind11/pull/4877#issuecomment-1752969127

* https://godbolt.org/z/Wa79nKz6e

* Add `PYBIND11_CONSTINIT`, but it does not work for the current use cases:

```
g++ -o pybind11/tests/test_numpy_array.os -c -std=c++20 -fPIC -fvisibility=hidden -O0 -g -Wall -Wextra -Wconversion -Wcast-qual -Wdeprecated -Wundef -Wnon-virtual-dtor -Wunused-result -Werror -isystem /usr/include/python3.11 -isystem /usr/include/eigen3 -DPYBIND11_STRICT_ASSERTS_CLASS_HOLDER_VS_TYPE_CASTER_MIX -DPYBIND11_ENABLE_TYPE_CASTER_ODR_GUARD_IF_AVAILABLE -DPYBIND11_TEST_BOOST -Ipybind11/include -I/usr/local/google/home/rwgk/forked/pybind11/include -I/usr/local/google/home/rwgk/clone/pybind11/include /usr/local/google/home/rwgk/forked/pybind11/tests/test_numpy_array.cpp
```

```
In file included from /usr/local/google/home/rwgk/forked/pybind11/tests/test_numpy_array.cpp:10:
/usr/local/google/home/rwgk/forked/pybind11/include/pybind11/numpy.h: In static member function ‘static pybind11::detail::npy_api& pybind11::detail::npy_api::get()’:
/usr/local/google/home/rwgk/forked/pybind11/include/pybind11/numpy.h:258:82: error: ‘constinit’ variable ‘api_init’ does not have a constant initializer
  258 |         PYBIND11_CONSTINIT static LazyInitializeAtLeastOnceDestroyNever<npy_api> api_init;
      |                                                                                  ^~~~~~~~
```

```
In file included from /usr/local/google/home/rwgk/forked/pybind11/tests/test_numpy_array.cpp:10:
/usr/local/google/home/rwgk/forked/pybind11/include/pybind11/numpy.h: In static member function ‘static pybind11::object& pybind11::dtype::_dtype_from_pep3118()’:
/usr/local/google/home/rwgk/forked/pybind11/include/pybind11/numpy.h:697:13: error: ‘constinit’ variable ‘imported_obj’ does not have a constant initializer
  697 |             imported_obj;
      |             ^~~~~~~~~~~~
```

* Revert "Add `PYBIND11_CONSTINIT`, but it does not work for the current use cases:"

This reverts commit f07b28bda9f91fb723aa898a21c81b6dd6857072.

* Reapply "Add `PYBIND11_CONSTINIT`, but it does not work for the current use cases:"

This reverts commit 36be645758aa82b576d24003808386bec6e55bf9.

* Add Default Member Initializer on `value_storage_` as suggested by @tkoeppe:

https://github.com/pybind/pybind11/pull/4877#issuecomment-1753201342

This fixes the errors reported under commit f07b28bda9f91fb723aa898a21c81b6dd6857072.

* Fix copy-paste-missed-a-change mishap in commit 88cec1152ab5576db19bab95c484672f06f5989a.

* Semi-paranoid placement new (based on https://github.com/pybind/pybind11/pull/4877#discussion_r1350573114).

* Move PYBIND11_CONSTINIT to detail/common.h

* Move code to the right places, rename new class and some variables.

* Fix oversight: update tests/extra_python_package/test_files.py

* Get the name right first.

* Use `std::call_once`, `std::atomic`, following a pattern developed by @tkoeppe

* Make the API more self-documenting (and possibly more easily reusable).

* google-clang-tidy IWYU fixes

* Rewrite comment as suggested by @tkoeppe

* Update test_exceptions.cpp and exceptions.rst

* Fix oversight in previous commit: add `PYBIND11_CONSTINIT`

* Make `get_stored()` non-const for simplicity.

As suggested by @tkoeppe: not seeing any reasonable use in which `get_stored` has to be const.

* Add comment regarding `KeyboardInterrupt` behavior, based heavily on information provided by @jbms.

* Add `assert(PyGILState_Check())` in `gil_scoped_release` ctor (simple & non-simple implementation) as suggested by @EthanSteinberg.

* Fix oversight in previous commit (missing include cassert).

* Remove use of std::atomic, leaving comments with rationale, why it is not needed.

* Rewrite comment re `std:optional` based on deeper reflection (aka 2nd thoughts).

* Additional comment with the conclusion of a discussion under PR #4877.

* https://github.com/pybind/pybind11/pull/4877#issuecomment-1757363179

* Small comment changes suggested by @tkoeppe.

Bumps [seanmiddleditch/gha-setup-ninja](https://github.com/seanmiddleditch/gha-setup-ninja) from 3 to 4.
- [Release notes](https://github.com/seanmiddleditch/gha-setup-ninja/releases)
- [Commits](https://github.com/seanmiddleditch/gha-setup-ninja/compare/v3...v4

)

---
updated-dependencies:
- dependency-name: seanmiddleditch/gha-setup-ninja
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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* chore(deps): update pre-commit hooks

updates:
- [github.com/psf/black-pre-commit-mirror: 23.7.0 → 23.9.1](https://github.com/psf/black-pre-commit-mirror/compare/23.7.0...23.9.1)
- [github.com/astral-sh/ruff-pre-commit: v0.0.287 → v0.0.292](https://github.com/astral-sh/ruff-pre-commit/compare/v0.0.287...v0.0.292)
- [github.com/codespell-project/codespell: v2.2.5 → v2.2.6](https://github.com/codespell-project/codespell/compare/v2.2.5...v2.2.6)
- [github.com/shellcheck-py/shellcheck-py: v0.9.0.5 → v0.9.0.6](https://github.com/shellcheck-py/shellcheck-py/compare/v0.9.0.5...v0.9.0.6)
- [github.com/PyCQA/pylint: v3.0.0a7 → v3.0.0](https://github.com/PyCQA/pylint/compare/v3.0.0a7...v3.0.0

)

* Update .pre-commit-config.yaml

* style: pre-commit fixes

* Update .pre-commit-config.yaml

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>

* MAINT: Include numpy._core imports

* style: pre-commit fixes

* Apply review comments

* style: pre-commit fixes

* Add no-inline attribute

* Select submodule name based on numpy version

* style: pre-commit fixes

* Update pre-commit check

* Add error_already_set and simplify if statement

* Update .pre-commit-config.yaml

Co-authored-by: Ralf W. Grosse-Kunstleve <rwgkio@gmail.com>

---------

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Co-authored-by: Ralf W. Grosse-Kunstleve <rwgkio@gmail.com>

Fixes oversights in PR #4570.

This change is fixing a Coverity AUTO_CAUSES_COPY issues.