* Test out Python 3.11 migration

* Clean up a bit

* Remove todo

* Test workaround

* Fix potential bug uncovered in 3.11

* Try to fix it more

* last ditch fix

* Revert. Tp-traverse isn't the problem

* Test workaround

* Try this hack

* Revert MRO changes

* Use f_back properly

* Qualify auto

* Update include/pybind11/pybind11.h

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Simplify code slightly

* Ensure co_varnames decref if dict_getitem throws

* Eager decref f_code

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

* Use sysconfig in Python >= 3.10

Rely on sysconfig for installation paths for Python >= 3.10. distutils
has been deprecated and will be removed.

Fixes: #3677

* Explicitly select the posix_prefix scheme for platinclude on Debian

Debian's default scheme is posix_local, for installing locally-built
packages to /usr/local/.  We want to find the Python headers in /usr/,
so search posix_prefix.

* chore: minor fixes for newer PyPys

* ci: fix issue with PyPy

* Clear local internals after finalizing interpreter

* Add descriptive comments

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

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

* cast: Qualify symbol usage in PYBIND11_TYPE_CASTER

Permits using macro outside of pybind11::detail

* fixup! review

* chore: add clang-format

* Removing check-style (Classic check-style)

Ported from @henryiii's https://github.com/pybind/pybind11/pull/3683/commits/53056b1b0eeb4136b0d7362a8261b6b59658e0a7

* Automatic clang-format changes (NO manual changes).

Co-authored-by: Henry Schreiner <henryschreineriii@gmail.com>

* Manual line breaks to pre-empt undesired `clang-format`ing.

Informed by work under https://github.com/pybind/pybind11/pull/3683:

https://github.com/pybind/pybind11/commit/60b7eb410fefe2b23aeb6906f2a9184e91b11a15

https://github.com/pybind/pybind11/commit/59572e65598b4b9f2c9ae0b8a0e5fcb6d65c7f92

* Manual curation of clang-format diffs involving source code comments.

Very labor-intensive and dull.

* Pulling .clang-format change from @henryiii's https://github.com/pybind/pybind11/pull/3683/commits/9057962d40ca520b9d26abbe0ff125796e2323dd

* Adding commonly used .clang-format `CommentPragmas:`

* Ensure short lambdas are allowed

Co-authored-by: Aaron Gokaslan <skylion.aaron@gmail.com>

chore(clang-tidy): Add clang-tidy rules: prefer-member-initializer and optin.performance.Padding (#3716)

* Add clang-tidy prefer-member-initializer

* Fix clang-tdy config

* Fix incorrect change

* Fix sorting of .clang-tidy

* Enable static downcast check

* Add inconsistent declaration naming check

* Adding readability-qualified-auto to .clang-tidy

Ported from @henryiii's https://github.com/pybind/pybind11/pull/3683/commits/287527f705c8badee8ba9f6278d691fe0450ae43

* fix: support Python < 3.6

Co-authored-by: Henry Schreiner <henryschreineriii@gmail.com>

Co-authored-by: Aaron Gokaslan <skylion.aaron@gmail.com>

clang-tidy automatic changes. NO manual changes.

Informed by experiments under PR #3698.

* chore: minor odd py version cleanup

* Update include/pybind11/pybind11.h

* fix: always make __index__ available

* Download catch for MinGw

* Fix rest of MinGW

* fix: update catch to 2.13.5 to fix glibc 2.34 failures

Update the downloaded Catch version to 2.13.5, in order to fix build
failure on glibc 2.34:

```
In file included from /usr/include/signal.h:328,
                 from /tmp/pybind11/.nox/tests-3-9/tmp/tests/catch/catch.hpp:8030,
                 from /tmp/pybind11/tests/test_embed/catch.cpp:13:
/tmp/pybind11/.nox/tests-3-9/tmp/tests/catch/catch.hpp:10818:58: error: call to non-‘constexpr’ function ‘long int sysconf(int)’
10818 |     static constexpr std::size_t sigStackSize = 32768 >= MINSIGSTKSZ ? 32768 : MINSIGSTKSZ;
      |                                                          ^~~~~~~~~~~
In file included from /usr/include/python3.9/Python.h:36,
                 from /tmp/pybind11/include/pybind11/detail/common.h:215,
                 from /tmp/pybind11/include/pybind11/pytypes.h:12,
                 from /tmp/pybind11/include/pybind11/cast.h:13,
                 from /tmp/pybind11/include/pybind11/attr.h:13,
                 from /tmp/pybind11/include/pybind11/pybind11.h:13,
                 from /tmp/pybind11/include/pybind11/embed.h:12,
                 from /tmp/pybind11/tests/test_embed/catch.cpp:4:
/usr/include/unistd.h:640:17: note: ‘long int sysconf(int)’ declared here
  640 | extern long int sysconf (int __name) __THROW;
      |                 ^~~~~~~
In file included from /tmp/pybind11/tests/test_embed/catch.cpp:13:
/tmp/pybind11/.nox/tests-3-9/tmp/tests/catch/catch.hpp:10877:45: error: size of array ‘altStackMem’ is not an integral constant-expression
10877 |     char FatalConditionHandler::altStackMem[sigStackSize] = {};
      |                                             ^~~~~~~~~~~~
```

The newest Catch version cannot be used yet because of regression:
https://github.com/catchorg/Catch2/pull/2364

* fix: add option for _ check, only define on pybind11

* Revert "fix: add option for _ check, only define on pybind11"

This reverts commit 86817db488c547816e21e20d678db318bb286384.

* fix: only undef _ for catch cpp creation.

Co-authored-by: Aaron Gokaslan <skylion.aaron@gmail.com>
Co-authored-by: Henry Schreiner <henryschreineriii@gmail.com>

* test: Strip whitespace when comparing numpy dtypes for 1.22 compat

Strip whitespace when comparing numpy dtype str() in order to preserve
test compatibility with both numpy 1.22 and older versions whose output
differ by whitespace.

Fixes #3680

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

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

* docs: update changelog for 2.9.1

* Update changelog.rst

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update changelog.rst

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

* Fix optimization bug introduced in #3650

* Add simple Python extension test for MVF

* Improve comments

* Clarify comment

* Clarify another comment

* Add test docstring

* Fix typo

* fix: support conda-forge

* Update setup.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

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

* Fix module extension detection for python 3.10

* Fix for python < 3.10

* Use importlib

* Add tests demonstrating smart_holder issues with multiple inheritance

* Propagate C++ multiple inheritance markers to all children

- Makes py::multiple_inheritance only needed in base classes hidden from pybind11

* msys ci: un-pin setup-msys2 action version

* msys ci: explicitly set PYTHONHOME and PYTHONPATH for c++ and interface tests (to workaround https://github.com/msys2/setup-msys2/issues/167)

Fix a typo in class.rst

Bumps [jwlawson/actions-setup-cmake](https://github.com/jwlawson/actions-setup-cmake) from 1.11 to 1.12.
- [Release notes](https://github.com/jwlawson/actions-setup-cmake/releases)
- [Commits](https://github.com/jwlawson/actions-setup-cmake/compare/v1.11...v1.12)

---
updated-dependencies:
- dependency-name: jwlawson/actions-setup-cmake
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>