* Auto select return value policy for clif_automatic

* Try fixing test failures

* Add more tests.

* remove comments

* Fix test failures

* Fix test failures

* Fix test failure for windows platform

* Fix clangtidy

Bumps [pypa/gh-action-pypi-publish](https://github.com/pypa/gh-action-pypi-publish) from 1.5.2 to 1.6.1.
- [Release notes](https://github.com/pypa/gh-action-pypi-publish/releases)
- [Commits](https://github.com/pypa/gh-action-pypi-publish/compare/v1.5.2...v1.6.1

)

---
updated-dependencies:
- dependency-name: pypa/gh-action-pypi-publish
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

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

Bumps [deadsnakes/action](https://github.com/deadsnakes/action) from 2.1.1 to 3.0.0.
- [Release notes](https://github.com/deadsnakes/action/releases)
- [Commits](https://github.com/deadsnakes/action/compare/v2.1.1...v3.0.0

)

---
updated-dependencies:
- dependency-name: deadsnakes/action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

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

* Replace 🐍 3.6 • ubuntu-latest • x64 -DPYBIND11_FINDPYTHON=ON -DCMAKE_CXX_FLAGS="-D_=1" with 3.9

* Revert "Replace 🐍 3.6 • ubuntu-latest • x64 -DPYBIND11_FINDPYTHON=ON -DCMAKE_CXX_FLAGS="-D_=1" with 3.9"

This reverts commit 3ec984e1ed7265ac152e6760c68a0bad97d5a2bd.

* Systematically change all active ubuntu-latest to ubuntu-20.04, except in upstream.yml

* Revert "Systematically change all active ubuntu-latest to ubuntu-20.04, except in upstream.yml"

This reverts commit cdfd99526a9d3c172691685ac17054bfe76590fc.

* Change only some ubuntu-latest to ubuntu-20.04

Show ODR VIOLATION DETECTED message only if `PYBIND11_DETAIL_TYPE_CASTER_ODR_GUARD_IMPL_DEBUG` is defined, to not clutter the test_gil_scoped.py output with many of these messages when `multiprocessing.set_start_method("forkserver")` is used.

chore: Convert direct multiprocessing.set_start_method("forkserver") call to a pytest fixture. (#4377)

* chore: convert multiprocessing set_spawn to fixture in pytest

* Switch to early return

Bumps [pypa/gh-action-pypi-publish](https://github.com/pypa/gh-action-pypi-publish) from 1.5.1 to 1.5.2.
- [Release notes](https://github.com/pypa/gh-action-pypi-publish/releases)
- [Commits](https://github.com/pypa/gh-action-pypi-publish/compare/v1.5.1...v1.5.2

)

---
updated-dependencies:
- dependency-name: pypa/gh-action-pypi-publish
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

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* scoped_interpreter overloaded ctor: PyConfig param

* style: pre-commit fixes

* refact: some logics extracted into funcs (precheck_interpreter, _initialize_interpreter); config_guard

* style: pre-commit fixes

* refact: scoped_config, some funcs hidden in detail ns

* refact: macro PYBIND11_PYCONFIG_SUPPORT_PY_VERSION + undef

* feat: PYBIND11_PYCONFIG_SUPPORT_PY_VERSION set to 3.8

* tests: Custom PyConfig

* ci: python 3.6 -> 3.8

* ci: reverted py 38 back  to 36; refact: initialize_interpreter overloads

* style: pre-commit fixes

* fix: readability-implicit-bool-conversion

* refact: each initialize_interpreter overloads in pybind11 ns

* Move `initialize_interpreter_pre_pyconfig()` into the `detail` namespace.

Move the `PYBIND11_PYCONFIG_SUPPORT_PY_VERSION_HEX` define down to where it is used for the first time, and check if it is defined already, so that it is possible to customize from the compilation command line, just in case there is some unforeseen issue for Python 3.8, 3.9, 3.10.

* tests: Add program dir to path, Custom PyConfig with argv

* refact: clang-formatted

* tests: Add-program-dir-to-path covers both scoped_interpreter overloads

* tests: Add-program-dir-to-path fixed

* tests: Add-program-dir-to-path py_version dependant validation

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Ralf W. Grosse-Kunstleve <rwgk@google.com>

* Introduce a new warning suppression system

* Switch to better name

* Nits

* Use `multiprocessing` `start_method` `"forkserver"`

Alternative to PR #4305

* Add link to comment under PR #4105

* Unconditionally `pytest.skip("DEADLOCK")` for PyPy Windows

* Remove `SKIP_IF_DEADLOCK` entirely, for simplicity. Hopefully this PR will resolve the deadlocks for good.

* Add "In a nutshell" comment, in response to request by @EricCousineau-TRI

* Use `PyEval_InitThreads()` as intended (actually matters only for Python 3.6).

* Add `if defined(WITH_THREAD)` condition.

https://docs.python.org/3.6/c-api/init.html#c.PyEval_InitThreads

> This function is not available when thread support is disabled at compile time.

* Fix oversight pointed out by @EricCousineau-TRI: Remove condition that is always false.

* Add macos_brew_install_llvm to ci.yml

Added block transferred from PR #4324

* `test_cross_module_exception_translator` xfail 'Homebrew Clang'

* Add `pip install numpy scipy` (tested already under PR #4324).

* fix pybind11Tools.cmake typo causing Unknown arguments

CMake Error at pybind11/tools/pybind11Tools.cmake:217 (if):
  if given arguments:
    "NOT" "MSVC" "AND" "NOT" "TEST" "MATCHES" "DEBUG|RELWITHDEBINFO"
  Unknown arguments specified
https://github.com/pybind/pybind11/issues/4325



* Apply the same fix in tools/pybind11NewTools.cmake

Co-authored-by: Ralf W. Grosse-Kunstleve <rwgk@google.com>

* Add windows_clang to ci.yml (previously tested under PRs #4321, #4319)

* Add `pip install --upgrade pip`, Show env, cosmetic changes

Already tested under PR #4321

* Illustrate bug in functional.h

* style: pre-commit fixes

* Make functional casting more robust / add workaround

* Make function_record* casting even more robust

* See if this fixes PyPy issue

* It still fails on PyPy sadly

* Do not make new CTOR just yet

* Fix test

* Add name to ensure correctness

* style: pre-commit fixes

* Clean up tests + remove ifdef guards

* Add comments

* Improve comments, error handling, and safety

* Fix compile error

* Fix magic logic

* Extract helper function

* Fix func signature

* move to local internals

* style: pre-commit fixes

* Switch to simpler design

* style: pre-commit fixes

* Move to function_record

* style: pre-commit fixes

* Switch to internals, update tests and docs

* Fix lint

* Oops, forgot to resolve last comment

* Fix typo

* Update in response to comments

* Implement suggestion to improve test

* Update comment

* Simple fixes

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

updates:
- [github.com/asottile/pyupgrade: v2.38.2 → v3.2.0](https://github.com/asottile/pyupgrade/compare/v2.38.2...v3.2.0)
- [github.com/psf/black: 22.8.0 → 22.10.0](https://github.com/psf/black/compare/22.8.0...22.10.0)
- [github.com/PyCQA/pylint: v2.15.3 → v2.15.5](https://github.com/PyCQA/pylint/compare/v2.15.3...v2.15.5)
- [github.com/pre-commit/mirrors-mypy: v0.981 → v0.982](https://github.com/pre-commit/mirrors-mypy/compare/v0.981...v0.982)
- [github.com/codespell-project/codespell: v2.2.1 → v2.2.2](https://github.com/codespell-project/codespell/compare/v2.2.1...v2.2.2

)

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

* docs: prepare for 2.10.1 release

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

* Update changelog.rst

* docs: update changelog with final list of PRs

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

* Update docs/changelog.rst

* chore: one more changelog bump

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

Background: #2999, #4105, #4283, #4284

In a nutshell:

* Only macOS actually needs `PYBIND11_EXPORT_EXCEPTION` (#4284).

* Evidently (#4283), under macOS `PYBIND11_EXPORT_EXCEPTION` does not run the risk of introducing ODR violations,

* but evidently (#4283) under Linux it does, in the presumably rare/unusual situation that `RTLD_GLOBAL` is used.

* Windows does no have the equivalent of `RTLD_GLOBAL`, therefore `PYBIND11_EXPORT_EXCEPTION` has no practical benefit, on the contrary, noisy warning suppression pragmas are needed, therefore it is best left empty.

* Fix & test for issue #4288 (unicode surrogate character in Python exception message).

* DRY `message_unavailable_exc`

* fix: add a constexpr

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

* style: pre-commit fixes

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

* Add macos_brew_install_llvm to ci.yml

Added block transferred from PR #4324

* `test_cross_module_exception_translator` xfail 'Homebrew Clang'

* Add `pip install numpy scipy` (tested already under PR #4324).

* fix pybind11Tools.cmake typo causing Unknown arguments

CMake Error at pybind11/tools/pybind11Tools.cmake:217 (if):
  if given arguments:
    "NOT" "MSVC" "AND" "NOT" "TEST" "MATCHES" "DEBUG|RELWITHDEBINFO"
  Unknown arguments specified
https://github.com/pybind/pybind11/issues/4325



* Apply the same fix in tools/pybind11NewTools.cmake

Co-authored-by: Ralf W. Grosse-Kunstleve <rwgk@google.com>

* Add windows_clang to ci.yml (previously tested under PRs #4321, #4319)

* Add `pip install --upgrade pip`, Show env, cosmetic changes

Already tested under PR #4321

* Illustrate bug in functional.h

* style: pre-commit fixes

* Make functional casting more robust / add workaround

* Make function_record* casting even more robust

* See if this fixes PyPy issue

* It still fails on PyPy sadly

* Do not make new CTOR just yet

* Fix test

* Add name to ensure correctness

* style: pre-commit fixes

* Clean up tests + remove ifdef guards

* Add comments

* Improve comments, error handling, and safety

* Fix compile error

* Fix magic logic

* Extract helper function

* Fix func signature

* move to local internals

* style: pre-commit fixes

* Switch to simpler design

* style: pre-commit fixes

* Move to function_record

* style: pre-commit fixes

* Switch to internals, update tests and docs

* Fix lint

* Oops, forgot to resolve last comment

* Fix typo

* Update in response to comments

* Implement suggestion to improve test

* Update comment

* Simple fixes

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

updates:
- [github.com/asottile/pyupgrade: v2.38.2 → v3.2.0](https://github.com/asottile/pyupgrade/compare/v2.38.2...v3.2.0)
- [github.com/psf/black: 22.8.0 → 22.10.0](https://github.com/psf/black/compare/22.8.0...22.10.0)
- [github.com/PyCQA/pylint: v2.15.3 → v2.15.5](https://github.com/PyCQA/pylint/compare/v2.15.3...v2.15.5)
- [github.com/pre-commit/mirrors-mypy: v0.981 → v0.982](https://github.com/pre-commit/mirrors-mypy/compare/v0.981...v0.982)
- [github.com/codespell-project/codespell: v2.2.1 → v2.2.2](https://github.com/codespell-project/codespell/compare/v2.2.1...v2.2.2

)

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

* docs: prepare for 2.10.1 release

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

* Update changelog.rst

* docs: update changelog with final list of PRs

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

* Update docs/changelog.rst

* chore: one more changelog bump

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

Background: #2999, #4105, #4283, #4284

In a nutshell:

* Only macOS actually needs `PYBIND11_EXPORT_EXCEPTION` (#4284).

* Evidently (#4283), under macOS `PYBIND11_EXPORT_EXCEPTION` does not run the risk of introducing ODR violations,

* but evidently (#4283) under Linux it does, in the presumably rare/unusual situation that `RTLD_GLOBAL` is used.

* Windows does no have the equivalent of `RTLD_GLOBAL`, therefore `PYBIND11_EXPORT_EXCEPTION` has no practical benefit, on the contrary, noisy warning suppression pragmas are needed, therefore it is best left empty.

* Fix & test for issue #4288 (unicode surrogate character in Python exception message).

* DRY `message_unavailable_exc`

* fix: add a constexpr

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

* style: pre-commit fixes

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