* 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

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

)

---
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  dependency-type: direct:production
  update-type: version-update:semver-patch
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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

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* 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

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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

)

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* 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

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* Add option to force the use of the PYPY GIL scoped acquire/release logic to support nested gil access, see https://github.com/pybind/pybind11/issues/1276 and https://github.com/pytorch/pytorch/issues/83101

* Apply suggestions from code review

* Update CMakeLists.txt

* docs: update upgrade guide

* Update docs/upgrade.rst

* All bells & whistles.

* Add Reminder to common.h, so that we will not forget to purge `!WITH_THREAD` branches when dropping Python 3.6

* New sentence instead of semicolon.

* Temporarily pull in snapshot of PR #4246

* Add `test_release_acquire`

* Add more unit tests for nested gil locking

* Add test_report_builtins_internals_keys

* Very minor enhancement: sort list only after filtering.

* Revert change in docs/upgrade.rst

* Add test_multi_acquire_release_cross_module, while also forcing unique PYBIND11_INTERNALS_VERSION for cross_module_gil_utils.cpp

* Hopefully fix appar...

* (bugfix): Improve bytes to str decoding error handling

* regroup test

* Further broaden tests

* Add another decode error test

* Fix bug in tests

* Reviewer suggestions

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

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

Standard library macro __cpp_lib_char8_t is only available
after including standard header

* fix: PyPy needs to overrite broken FindPythonInterp values

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

* fix: add flag to opt-in to new (cross-compile) behavior

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

* Apply suggestions from code review

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

* Fix casts to void*

* Improve tests

* style: pre-commit fixes

* remove c style cast

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
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* Revert "chore: perfectly forward all make_iterator args (#3980)"

This reverts commit 8da58da5.

* Redo unrelated optimization in commit

* Add tests for ambiguous overloads

* Revert "feat: add entrypoint for cmake modules dir (#4258)"

This reverts commit 1d4a65e2.

* docs: revert changelog mention too

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

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

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

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

* Simply replace "22.3" with "22.9" to see what happens.

* Remove PYBIND11_TEST_FILTER to see what happens.

* Revert "Remove PYBIND11_TEST_FILTER to see what happens."

This reverts commit 0cba2cef0c5c5bcbf57cad219c7d5dfb0cda241c.

* Remove only test_smart_ptr.cpp to see what happens.

* Revert "Remove only test_smart_ptr.cpp to see what happens."

This reverts commit 8e9df22c85292003abcab50260393e547567fc18.

* Remove only test_virtual_functions.cpp to see what happens.

* First draft of Eigen::Tensor support

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

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

* Fix build errors

* Weird allocator stuff?

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

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

* Remove unused + additional allocator junk

* Disable warning

* Use constexpr

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

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

* clang tidy fixes

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

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

* Resolve comments

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

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

* Remove auto constexpr function

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

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

* Try again for older C++

* Oops forgot constexpr

* Move...

* bugfix: contains now throws an exception if the key is not hashable

* Fix tests and improve robustness

* Remove todo

* Workaround PyPy corner case

* PyPy xfail

* Fix typo

* fix xfail

* Make clang-tidy happy

* Remove redundant exc checking

Bumps [ilammy/msvc-dev-cmd](https://github.com/ilammy/msvc-dev-cmd) from 1.11.0 to 1.12.0.
- [Release notes](https://github.com/ilammy/msvc-dev-cmd/releases)
- [Commits](https://github.com/ilammy/msvc-dev-cmd/compare/v1.11.0...v1.12.0

)

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Use `PyCapsule_Destructor` (part of the stable Python ABI) instead of spelling out the C `typedef`.

The deprecation message is misleading. Replace with a message pointing to another existing ctor.

Background: According to @wjakob the original motivation for deprecating the ctor (in PR #752) was to hide Python C API details, but PR #902 brought those back with a new ctor, it cannot be avoided. Having a `PyCapsule_Destructor` or a `void (*destructor)(void *)` are two separate and valid use cases.

* Improve pycapsule error handling corner cases

* Handle another corner case

* Simplify err handling code