Merge branch 'master' into v2.10

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -6,7 +6,8 @@ body:
   - type: markdown
     attributes:
       value: |
-        Maintainers will only make a best effort to triage PRs. Please do your best to make the issue as easy to act on as possible, and only open if clearly a problem with pybind11 (ask first if unsure).
+        Please do your best to make the issue as easy to act on as possible, and only submit here if there is clearly a problem with pybind11 (ask first if unsure). **Note that a reproducer in a PR is much more likely to get immediate attention.**
+
   - type: checkboxes
     id: steps
     attributes:
@@ -20,6 +21,13 @@ body:
         - label: Consider asking first in the [Gitter chat room](https://gitter.im/pybind/Lobby) or in a [Discussion](https:/pybind/pybind11/discussions/new).
           required: false
 
+  - type: input
+    id: version
+    attributes:
+      label: What version (or hash if on master) of pybind11 are you using?
+    validations:
+      required: true
+
   - type: textarea
     id: description
     attributes:
@@ -40,6 +48,14 @@ body:
         The code should be minimal, have no external dependencies, isolate the
         function(s) that cause breakage. Submit matched and complete C++ and
         Python snippets that can be easily compiled and run to diagnose the
-        issue. If possible, make a PR with a new, failing test to give us a
-        starting point to work on!
+        issue. — Note that a reproducer in a PR is much more likely to get
+        immediate attention: failing tests in the pybind11 CI are the best
+        starting point for working out fixes.
       render: text
+
+  - type: input
+    id: regression
+    attributes:
+      label: Is this a regression? Put the last known working version here if it is.
+      description: Put the last known working version here if this is a regression.
+      value: Not a regression

.github/workflows/ci.yml

@@ -17,6 +17,8 @@ env:
   PIP_ONLY_BINARY: numpy
   FORCE_COLOR: 3
   PYTEST_TIMEOUT: 300
+  # For cmake:
+  VERBOSE: 1
 
 jobs:
   # This is the "main" test suite, which tests a large number of different
@@ -25,7 +27,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        runs-on: [ubuntu-latest, windows-2022, macos-latest]
+        runs-on: [ubuntu-20.04, windows-2022, macos-latest]
         python:
         - '3.6'
         - '3.9'
@@ -42,12 +44,12 @@ jobs:
         # We support an optional key: args, for cmake args
         include:
           # Just add a key
-          - runs-on: ubuntu-latest
+          - runs-on: ubuntu-20.04
             python: '3.6'
             args: >
               -DPYBIND11_FINDPYTHON=ON
               -DCMAKE_CXX_FLAGS="-D_=1"
-          - runs-on: ubuntu-latest
+          - runs-on: ubuntu-20.04
             python: 'pypy-3.8'
             args: >
               -DPYBIND11_FINDPYTHON=ON
@@ -194,13 +196,13 @@ jobs:
           python-debug: false
 
     name: "🐍 ${{ matrix.python-version }}${{ matrix.python-debug && '-dbg' || '' }} (deadsnakes)${{ matrix.valgrind && ' • Valgrind' || '' }} • x64"
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
 
     steps:
     - uses: actions/checkout@v3
 
     - name: Setup Python ${{ matrix.python-version }} (deadsnakes)
-      uses: deadsnakes/action@v2.1.1
+      uses: deadsnakes/action@v3.0.0
       with:
         python-version: ${{ matrix.python-version }}
         debug: ${{ matrix.python-debug }}
@@ -918,7 +920,7 @@ jobs:
     - name: Configure C++11
       # LTO leads to many undefined reference like
       # `pybind11::detail::function_call::function_call(pybind11::detail::function_call&&)
-      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=11 -DCMAKE_VERBOSE_MAKEFILE=ON -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON -S . -B build
+      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=11 -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON -S . -B build
 
     - name: Build C++11
       run: cmake --build build -j 2
@@ -936,7 +938,7 @@ jobs:
       run: git clean -fdx
 
     - name: Configure C++14
-      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=14 -DCMAKE_VERBOSE_MAKEFILE=ON -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON -S . -B build2
+      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=14 -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON -S . -B build2
 
     - name: Build C++14
       run: cmake --build build2 -j 2
@@ -954,7 +956,7 @@ jobs:
       run: git clean -fdx
 
     - name: Configure C++17
-      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=17 -DCMAKE_VERBOSE_MAKEFILE=ON -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON -S . -B build3
+      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=17 -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON -S . -B build3
 
     - name: Build C++17
       run: cmake --build build3 -j 2
@@ -967,3 +969,138 @@ jobs:
 
     - name: Interface test C++17
       run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build3 --target test_cmake_build
+
+  windows_clang:
+
+    strategy:
+      matrix:
+        os: [windows-latest]
+        python: ['3.10']
+
+    runs-on: "${{ matrix.os }}"
+
+    name: "🐍 ${{ matrix.python }} • ${{ matrix.os }} • clang-latest"
+
+    steps:
+      - name: Show env
+        run: env
+
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Set up Clang
+        uses: egor-tensin/setup-clang@v1
+
+      - name: Setup Python ${{ matrix.python }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python }}
+
+      - name: Update CMake
+        uses: jwlawson/actions-setup-cmake@v1.13
+
+      - name: Install ninja-build tool
+        uses: seanmiddleditch/gha-setup-ninja@v3
+
+      - name: Run pip installs
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install -r tests/requirements.txt
+
+      - name: Show Clang++ version
+        run: clang++ --version
+
+      - name: Show CMake version
+        run: cmake --version
+
+      # TODO: WERROR=ON
+      - name: Configure Clang
+        run: >
+          cmake -G Ninja -S . -B .
+          -DPYBIND11_WERROR=OFF
+          -DPYBIND11_SIMPLE_GIL_MANAGEMENT=OFF
+          -DDOWNLOAD_CATCH=ON
+          -DDOWNLOAD_EIGEN=ON
+          -DCMAKE_CXX_COMPILER=clang++
+          -DCMAKE_CXX_STANDARD=17
+
+      - name: Build
+        run: cmake --build . -j 2
+
+      - name: Python tests
+        run: cmake --build . --target pytest -j 2
+
+      - name: C++ tests
+        run: cmake --build . --target cpptest -j 2
+
+      - name: Interface test
+        run: cmake --build . --target test_cmake_build -j 2
+
+      - name: Clean directory
+        run: git clean -fdx
+
+  macos_brew_install_llvm:
+    name: "macos-latest • brew install llvm"
+    runs-on: macos-latest
+
+    env:
+      # https://apple.stackexchange.com/questions/227026/how-to-install-recent-clang-with-homebrew
+      LDFLAGS: '-L/usr/local/opt/llvm/lib -Wl,-rpath,/usr/local/opt/llvm/lib'
+
+    steps:
+      - name: Update PATH
+        run: echo "/usr/local/opt/llvm/bin" >> $GITHUB_PATH
+
+      - name: Show env
+        run: env
+
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Show Clang++ version before brew install llvm
+        run: clang++ --version
+
+      - name: brew install llvm
+        run: brew install llvm
+
+      - name: Show Clang++ version after brew install llvm
+        run: clang++ --version
+
+      - name: Update CMake
+        uses: jwlawson/actions-setup-cmake@v1.13
+
+      - name: Run pip installs
+        run: |
+          python3 -m pip install --upgrade pip
+          python3 -m pip install -r tests/requirements.txt
+          python3 -m pip install numpy
+          python3 -m pip install scipy
+
+      - name: Show CMake version
+        run: cmake --version
+
+      - name: CMake Configure
+        run: >
+          cmake -S . -B .
+          -DPYBIND11_WERROR=ON
+          -DPYBIND11_SIMPLE_GIL_MANAGEMENT=OFF
+          -DDOWNLOAD_CATCH=ON
+          -DDOWNLOAD_EIGEN=ON
+          -DCMAKE_CXX_COMPILER=clang++
+          -DCMAKE_CXX_STANDARD=17
+          -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+
+      - name: Build
+        run: cmake --build . -j 2
+
+      - name: Python tests
+        run: cmake --build . --target pytest -j 2
+
+      - name: C++ tests
+        run: cmake --build . --target cpptest -j 2
+
+      - name: Interface test
+        run: cmake --build . --target test_cmake_build -j 2
+
+      - name: Clean directory
+        run: git clean -fdx

.github/workflows/configure.yml

@@ -9,6 +9,10 @@ on:
       - stable
       - v*
 
+env:
+  # For cmake:
+  VERBOSE: 1
+
 jobs:
   # This tests various versions of CMake in various combinations, to make sure
   # the configure step passes.
@@ -16,12 +20,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        runs-on: [ubuntu-latest, macos-latest, windows-latest]
+        runs-on: [ubuntu-20.04, macos-latest, windows-latest]
         arch: [x64]
         cmake: ["3.23"]
 
         include:
-        - runs-on: ubuntu-latest
+        - runs-on: ubuntu-20.04
           arch: x64
           cmake: 3.4
 

.github/workflows/format.yml

@@ -14,6 +14,8 @@ on:
 
 env:
   FORCE_COLOR: 3
+  # For cmake:
+  VERBOSE: 1
 
 jobs:
   pre-commit:

.github/workflows/labeler.yml

@@ -10,7 +10,11 @@ jobs:
     steps:
 
     - uses: actions/labeler@main
-      if: github.event.pull_request.merged == true
+      if: >
+        github.event.pull_request.merged == true &&
+        !startsWith(github.event.pull_request.title, 'chore(deps):') &&
+        !startsWith(github.event.pull_request.title, 'ci(fix):') &&
+        !startsWith(github.event.pull_request.title, 'docs(changelog):')
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         configuration-path: .github/labeler_merged.yml

.github/workflows/pip.yml

@@ -98,13 +98,13 @@ jobs:
     - uses: actions/download-artifact@v3
 
     - name: Publish standard package
-      uses: pypa/gh-action-pypi-publish@v1.5.1
+      uses: pypa/gh-action-pypi-publish@v1.6.4
       with:
         password: ${{ secrets.pypi_password }}
         packages_dir: standard/
 
     - name: Publish global package
-      uses: pypa/gh-action-pypi-publish@v1.5.1
+      uses: pypa/gh-action-pypi-publish@v1.6.4
       with:
         password: ${{ secrets.pypi_password_global }}
         packages_dir: global/

.github/workflows/upstream.yml

@@ -11,6 +11,8 @@ concurrency:
 
 env:
   PIP_ONLY_BINARY: numpy
+  # For cmake:
+  VERBOSE: 1
 
 jobs:
   standard:

.gitignore

@@ -43,3 +43,4 @@ pybind11Targets.cmake
 /pybind11/share/*
 /docs/_build/*
 .ipynb_checkpoints/
+tests/main.cpp

.pre-commit-config.yaml

@@ -24,7 +24,7 @@ exclude: ^tools/JoinPaths.cmake$
 repos:
 # Standard hooks
 - repo: https://github.com/pre-commit/pre-commit-hooks
-  rev: "v4.3.0"
+  rev: "v4.4.0"
   hooks:
   - id: check-added-large-files
   - id: check-case-conflict
@@ -41,7 +41,7 @@ repos:
 
 # Upgrade old Python syntax
 - repo: https://github.com/asottile/pyupgrade
-  rev: "v2.38.2"
+  rev: "v3.3.0"
   hooks:
   - id: pyupgrade
     args: [--py36-plus]
@@ -54,7 +54,7 @@ repos:
 
 # Black, the code formatter, natively supports pre-commit
 - repo: https://github.com/psf/black
-  rev: "22.8.0" # Keep in sync with blacken-docs
+  rev: "22.10.0" # Keep in sync with blacken-docs
   hooks:
   - id: black
 
@@ -64,7 +64,7 @@ repos:
   hooks:
   - id: blacken-docs
     additional_dependencies:
-    - black==22.8.0 # keep in sync with black hook
+    - black==22.10.0 # keep in sync with black hook
 
 # Changes tabs to spaces
 - repo: https://github.com/Lucas-C/pre-commit-hooks
@@ -80,7 +80,7 @@ repos:
 
 # Autoremoves unused imports
 - repo: https://github.com/hadialqattan/pycln
-  rev: "v2.1.1"
+  rev: "v2.1.2"
   hooks:
   - id: pycln
     stages: [manual]
@@ -108,7 +108,7 @@ repos:
 
 # Flake8 also supports pre-commit natively (same author)
 - repo: https://github.com/PyCQA/flake8
-  rev: "5.0.4"
+  rev: "6.0.0"
   hooks:
   - id: flake8
     exclude: ^(docs/.*|tools/.*)$
@@ -116,7 +116,7 @@ repos:
 
 # PyLint has native support - not always usable, but works for us
 - repo: https://github.com/PyCQA/pylint
-  rev: "v2.15.3"
+  rev: "v2.15.8"
   hooks:
   - id: pylint
     files: ^pybind11
@@ -132,7 +132,7 @@ repos:
 
 # Check static types with mypy
 - repo: https://github.com/pre-commit/mirrors-mypy
-  rev: "v0.981"
+  rev: "v0.991"
   hooks:
   - id: mypy
     args: []
@@ -141,7 +141,7 @@ repos:
 
 # Checks the manifest for missing files (native support)
 - repo: https://github.com/mgedmin/check-manifest
-  rev: "0.48"
+  rev: "0.49"
   hooks:
   - id: check-manifest
     # This is a slow hook, so only run this if --hook-stage manual is passed
@@ -152,7 +152,7 @@ repos:
 # Use tools/codespell_ignore_lines_from_errors.py
 # to rebuild .codespell-ignore-lines
 - repo: https://github.com/codespell-project/codespell
-  rev: "v2.2.1"
+  rev: "v2.2.2"
   hooks:
   - id: codespell
     exclude: ".supp$"
@@ -175,7 +175,7 @@ repos:
 
 # Clang format the codebase automatically
 - repo: https://github.com/pre-commit/mirrors-clang-format
-  rev: "v14.0.6"
+  rev: "v15.0.4"
   hooks:
   - id: clang-format
     types_or: [c++, c, cuda]

CMakeLists.txt

@@ -126,6 +126,8 @@ set(PYBIND11_HEADERS
     include/pybind11/complex.h
     include/pybind11/options.h
     include/pybind11/eigen.h
+    include/pybind11/eigen/matrix.h
+    include/pybind11/eigen/tensor.h
     include/pybind11/embed.h
     include/pybind11/eval.h
     include/pybind11/gil.h

docs/advanced/exceptions.rst

@@ -177,9 +177,12 @@ section.
     may be explicitly (re-)thrown to delegate it to the other,
     previously-declared existing exception translators.
 
-    Note that ``libc++`` and ``libstdc++`` `behave differently <https://stackoverflow.com/questions/19496643/using-clang-fvisibility-hidden-and-typeinfo-and-type-erasure/28827430>`_
-    with ``-fvisibility=hidden``. Therefore exceptions that are used across ABI boundaries need to be explicitly exported, as exercised in ``tests/test_exceptions.h``.
-    See also: "Problems with C++ exceptions" under `GCC Wiki <https://gcc.gnu.org/wiki/Visibility>`_.
+    Note that ``libc++`` and ``libstdc++`` `behave differently under macOS
+    <https://stackoverflow.com/questions/19496643/using-clang-fvisibility-hidden-and-typeinfo-and-type-erasure/28827430>`_
+    with ``-fvisibility=hidden``. Therefore exceptions that are used across ABI
+    boundaries need to be explicitly exported, as exercised in
+    ``tests/test_exceptions.h``. See also:
+    "Problems with C++ exceptions" under `GCC Wiki <https://gcc.gnu.org/wiki/Visibility>`_.
 
 
 Local vs Global Exception Translators

docs/advanced/misc.rst

@@ -324,6 +324,15 @@ The class ``options`` allows you to selectively suppress auto-generated signatur
         m.def("add", [](int a, int b) { return a + b; }, "A function which adds two numbers");
     }
 
+pybind11 also appends all members of an enum to the resulting enum docstring.
+This default behavior can be disabled by using the ``disable_enum_members_docstring()``
+function of the ``options`` class.
+
+With ``disable_user_defined_docstrings()`` all user defined docstrings of
+``module_::def()``, ``class_::def()`` and ``enum_()`` are disabled, but the
+function signatures and enum members are included in the docstring, unless they
+are disabled separately.
+
 Note that changes to the settings affect only function bindings created during the
 lifetime of the ``options`` instance. When it goes out of scope at the end of the module's init function,
 the default settings are restored to prevent unwanted side effects.

docs/changelog.rst

@@ -15,6 +15,60 @@ IN DEVELOPMENT
 
 Changes will be summarized here periodically.
 
+Version 2.10.2 (Dec 20, 2022)
+-----------------------------
+
+Changes:
+
+* ``scoped_interpreter`` constructor taking ``PyConfig``.
+  `#4330 <https://github.com/pybind/pybind11/pull/4330>`_
+
+* ``pybind11/eigen/tensor.h`` adds converters to and from ``Eigen::Tensor`` and
+  ``Eigen::TensorMap``.
+  `#4201 <https://github.com/pybind/pybind11/pull/4201>`_
+
+* ``PyGILState_Check()``'s  were integrated to ``pybind11::handle``
+  ``inc_ref()`` & ``dec_ref()``. The added GIL checks are guarded by
+  ``PYBIND11_ASSERT_GIL_HELD_INCREF_DECREF``, which is the default only if
+  ``NDEBUG`` is not defined.
+  `#4246 <https://github.com/pybind/pybind11/pull/4246>`_
+
+* Add option for enable/disable enum members in docstring.
+  `#2768 <https://github.com/pybind/pybind11/pull/2768>`_
+
+* Fixed typing of ``KeysView``, ``ValuesView`` and ``ItemsView`` in ``bind_map``.
+  `#4353 <https://github.com/pybind/pybind11/pull/4353>`_
+
+Bug fixes:
+
+* Bug fix affecting only Python 3.6 under very specific, uncommon conditions:
+  move ``PyEval_InitThreads()`` call to the correct location.
+  `#4350 <https://github.com/pybind/pybind11/pull/4350>`_
+
+* Fix segfault bug when passing foreign native functions to functional.h.
+  `#4254 <https://github.com/pybind/pybind11/pull/4254>`_
+
+Build system improvements:
+
+* Support setting PYTHON_LIBRARIES manually for Windows ARM cross-compilation
+  (classic mode).
+  `#4406 <https://github.com/pybind/pybind11/pull/4406>`_
+
+* Extend IPO/LTO detection for ICX (a.k.a IntelLLVM) compiler.
+  `#4402 <https://github.com/pybind/pybind11/pull/4402>`_
+
+* Allow calling ``find_package(pybind11 CONFIG)`` multiple times from separate
+  directories in the same CMake project and properly link Python (new mode).
+  `#4401 <https://github.com/pybind/pybind11/pull/4401>`_
+
+* ``multiprocessing_set_spawn`` in pytest fixture for added safety.
+  `#4377 <https://github.com/pybind/pybind11/pull/4377>`_
+
+* Fixed a bug in two pybind11/tools cmake scripts causing "Unknown arguments specified" errors.
+  `#4327 <https://github.com/pybind/pybind11/pull/4327>`_
+
+
+
 Version 2.10.1 (Oct 31, 2022)
 -----------------------------
 
@@ -95,7 +149,6 @@ Bug fixes:
   finalization.
   `#4192 <https://github.com/pybind/pybind11/pull/4192>`_
 
-
 Performance and style:
 
 * Reserve space in set and STL map casters if possible. This will prevent

include/pybind11/cast.h

@@ -29,6 +29,9 @@
 #include <vector>
 
 PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+
+PYBIND11_WARNING_DISABLE_MSVC(4127)
+
 PYBIND11_NAMESPACE_BEGIN(detail)
 
 template <typename type, typename SFINAE = void>
@@ -88,7 +91,8 @@ public:
     template <typename T_,                                                                        \
               ::pybind11::detail::enable_if_t<                                                    \
                   std::is_same<type, ::pybind11::detail::remove_cv_t<T_>>::value,                 \
-                  int> = 0>                                                                       \
+                  int>                                                                            \
+              = 0>                                                                                \
     static ::pybind11::handle cast(                                                               \
         T_ *src, ::pybind11::return_value_policy policy, ::pybind11::handle parent) {             \
         if (!src)                                                                                 \
@@ -389,7 +393,7 @@ struct string_caster {
 
         // For UTF-8 we avoid the need for a temporary `bytes` object by using
         // `PyUnicode_AsUTF8AndSize`.
-        if (PYBIND11_SILENCE_MSVC_C4127(UTF_N == 8)) {
+        if (UTF_N == 8) {
             Py_ssize_t size = -1;
             const auto *buffer
                 = reinterpret_cast<const CharT *>(PyUnicode_AsUTF8AndSize(load_src.ptr(), &size));
@@ -416,7 +420,7 @@ struct string_caster {
             = reinterpret_cast<const CharT *>(PYBIND11_BYTES_AS_STRING(utfNbytes.ptr()));
         size_t length = (size_t) PYBIND11_BYTES_SIZE(utfNbytes.ptr()) / sizeof(CharT);
         // Skip BOM for UTF-16/32
-        if (PYBIND11_SILENCE_MSVC_C4127(UTF_N > 8)) {
+        if (UTF_N > 8) {
             buffer++;
             length--;
         }
@@ -572,7 +576,7 @@ public:
         // figure out how long the first encoded character is in bytes to distinguish between these
         // two errors.  We also allow want to allow unicode characters U+0080 through U+00FF, as
         // those can fit into a single char value.
-        if (PYBIND11_SILENCE_MSVC_C4127(StringCaster::UTF_N == 8) && str_len > 1 && str_len <= 4) {
+        if (StringCaster::UTF_N == 8 && str_len > 1 && str_len <= 4) {
             auto v0 = static_cast<unsigned char>(value[0]);
             // low bits only: 0-127
             // 0b110xxxxx - start of 2-byte sequence
@@ -598,7 +602,7 @@ public:
         // UTF-16 is much easier: we can only have a surrogate pair for values above U+FFFF, thus a
         // surrogate pair with total length 2 instantly indicates a range error (but not a "your
         // string was too long" error).
-        else if (PYBIND11_SILENCE_MSVC_C4127(StringCaster::UTF_N == 16) && str_len == 2) {
+        else if (StringCaster::UTF_N == 16 && str_len == 2) {
             one_char = static_cast<CharT>(value[0]);
             if (one_char >= 0xD800 && one_char < 0xE000) {
                 throw value_error("Character code point not in range(0x10000)");

include/pybind11/detail/common.h

@@ -11,14 +11,75 @@
 
 #define PYBIND11_VERSION_MAJOR 2
 #define PYBIND11_VERSION_MINOR 10
-#define PYBIND11_VERSION_PATCH 1
+#define PYBIND11_VERSION_PATCH 2
 
 // Similar to Python's convention: https://docs.python.org/3/c-api/apiabiversion.html
 // Additional convention: 0xD = dev
-#define PYBIND11_VERSION_HEX 0x020A0100
+#define PYBIND11_VERSION_HEX 0x020A0200
+
+// Define some generic pybind11 helper macros for warning management.
+//
+// Note that compiler-specific push/pop pairs are baked into the
+// PYBIND11_NAMESPACE_BEGIN/PYBIND11_NAMESPACE_END pair of macros. Therefore manual
+// PYBIND11_WARNING_PUSH/PYBIND11_WARNING_POP are usually only needed in `#include` sections.
+//
+// If you find you need to suppress a warning, please try to make the suppression as local as
+// possible using these macros. Please also be sure to push/pop with the pybind11 macros. Please
+// only use compiler specifics if you need to check specific versions, e.g. Apple Clang vs. vanilla
+// Clang.
+#if defined(_MSC_VER)
+#    define PYBIND11_COMPILER_MSVC
+#    define PYBIND11_PRAGMA(...) __pragma(__VA_ARGS__)
+#    define PYBIND11_WARNING_PUSH PYBIND11_PRAGMA(warning(push))
+#    define PYBIND11_WARNING_POP PYBIND11_PRAGMA(warning(pop))
+#elif defined(__INTEL_COMPILER)
+#    define PYBIND11_COMPILER_INTEL
+#    define PYBIND11_PRAGMA(...) _Pragma(#__VA_ARGS__)
+#    define PYBIND11_WARNING_PUSH PYBIND11_PRAGMA(warning push)
+#    define PYBIND11_WARNING_POP PYBIND11_PRAGMA(warning pop)
+#elif defined(__clang__)
+#    define PYBIND11_COMPILER_CLANG
+#    define PYBIND11_PRAGMA(...) _Pragma(#__VA_ARGS__)
+#    define PYBIND11_WARNING_PUSH PYBIND11_PRAGMA(clang diagnostic push)
+#    define PYBIND11_WARNING_POP PYBIND11_PRAGMA(clang diagnostic push)
+#elif defined(__GNUC__)
+#    define PYBIND11_COMPILER_GCC
+#    define PYBIND11_PRAGMA(...) _Pragma(#__VA_ARGS__)
+#    define PYBIND11_WARNING_PUSH PYBIND11_PRAGMA(GCC diagnostic push)
+#    define PYBIND11_WARNING_POP PYBIND11_PRAGMA(GCC diagnostic pop)
+#endif
+
+#ifdef PYBIND11_COMPILER_MSVC
+#    define PYBIND11_WARNING_DISABLE_MSVC(name) PYBIND11_PRAGMA(warning(disable : name))
+#else
+#    define PYBIND11_WARNING_DISABLE_MSVC(name)
+#endif
+
+#ifdef PYBIND11_COMPILER_CLANG
+#    define PYBIND11_WARNING_DISABLE_CLANG(name) PYBIND11_PRAGMA(clang diagnostic ignored name)
+#else
+#    define PYBIND11_WARNING_DISABLE_CLANG(name)
+#endif
 
-#define PYBIND11_NAMESPACE_BEGIN(name) namespace name {
-#define PYBIND11_NAMESPACE_END(name) }
+#ifdef PYBIND11_COMPILER_GCC
+#    define PYBIND11_WARNING_DISABLE_GCC(name) PYBIND11_PRAGMA(GCC diagnostic ignored name)
+#else
+#    define PYBIND11_WARNING_DISABLE_GCC(name)
+#endif
+
+#ifdef PYBIND11_COMPILER_INTEL
+#    define PYBIND11_WARNING_DISABLE_INTEL(name) PYBIND11_PRAGMA(warning disable name)
+#else
+#    define PYBIND11_WARNING_DISABLE_INTEL(name)
+#endif
+
+#define PYBIND11_NAMESPACE_BEGIN(name)                                                            \
+    namespace name {                                                                              \
+    PYBIND11_WARNING_PUSH
+
+#define PYBIND11_NAMESPACE_END(name)                                                              \
+    PYBIND11_WARNING_POP                                                                          \
+    }
 
 // Robust support for some features and loading modules compiled against different pybind versions
 // requires forcing hidden visibility on pybind code, so we enforce this by setting the attribute
@@ -96,13 +157,10 @@
 #endif
 
 #if !defined(PYBIND11_EXPORT_EXCEPTION)
-#    ifdef __MINGW32__
-// workaround for:
-// error: 'dllexport' implies default visibility, but xxx has already been declared with a
-// different visibility
-#        define PYBIND11_EXPORT_EXCEPTION
-#    else
+#    if defined(__apple_build_version__)
 #        define PYBIND11_EXPORT_EXCEPTION PYBIND11_EXPORT
+#    else
+#        define PYBIND11_EXPORT_EXCEPTION
 #    endif
 #endif
 
@@ -154,9 +212,9 @@
 
 /// Include Python header, disable linking to pythonX_d.lib on Windows in debug mode
 #if defined(_MSC_VER)
-#    pragma warning(push)
+PYBIND11_WARNING_PUSH
+PYBIND11_WARNING_DISABLE_MSVC(4505)
 // C4505: 'PySlice_GetIndicesEx': unreferenced local function has been removed (PyPy only)
-#    pragma warning(disable : 4505)
 #    if defined(_DEBUG) && !defined(Py_DEBUG)
 // Workaround for a VS 2022 issue.
 // NOTE: This workaround knowingly violates the Python.h include order requirement:
@@ -239,7 +297,7 @@
 #        define _DEBUG
 #        undef PYBIND11_DEBUG_MARKER
 #    endif
-#    pragma warning(pop)
+PYBIND11_WARNING_POP
 #endif
 
 #include <cstddef>
@@ -265,6 +323,15 @@
 #    define PYBIND11_HAS_U8STRING
 #endif
 
+// See description of PR #4246:
+#if !defined(NDEBUG) && !defined(PY_ASSERT_GIL_HELD_INCREF_DECREF)                                \
+    && !(defined(PYPY_VERSION)                                                                    \
+         && defined(_MSC_VER)) /* PyPy Windows: pytest hangs indefinitely at the end of the       \
+                                  process (see PR #4268) */                                       \
+    && !defined(PYBIND11_ASSERT_GIL_HELD_INCREF_DECREF)
+#    define PYBIND11_ASSERT_GIL_HELD_INCREF_DECREF
+#endif
+
 // #define PYBIND11_STR_LEGACY_PERMISSIVE
 // If DEFINED, pybind11::str can hold PyUnicodeObject or PyBytesObject
 //             (probably surprising and never documented, but this was the
@@ -904,12 +971,6 @@ using expand_side_effects = bool[];
 
 PYBIND11_NAMESPACE_END(detail)
 
-#if defined(_MSC_VER)
-#    pragma warning(push)
-#    pragma warning(disable : 4275)
-//     warning C4275: An exported class was derived from a class that wasn't exported.
-//     Can be ignored when derived from a STL class.
-#endif
 /// C++ bindings of builtin Python exceptions
 class PYBIND11_EXPORT_EXCEPTION builtin_exception : public std::runtime_error {
 public:
@@ -917,9 +978,6 @@ public:
     /// Set the error using the Python C API
     virtual void set_error() const = 0;
 };
-#if defined(_MSC_VER)
-#    pragma warning(pop)
-#endif
 
 #define PYBIND11_RUNTIME_EXCEPTION(name, type)                                                    \
     class PYBIND11_EXPORT_EXCEPTION name : public builtin_exception {                             \
@@ -1148,17 +1206,6 @@ constexpr
 #    define PYBIND11_WORKAROUND_INCORRECT_GCC_UNUSED_BUT_SET_PARAMETER(...)
 #endif
 
-#if defined(_MSC_VER) // All versions (as of July 2021).
-
-// warning C4127: Conditional expression is constant
-constexpr inline bool silence_msvc_c4127(bool cond) { return cond; }
-
-#    define PYBIND11_SILENCE_MSVC_C4127(...) ::pybind11::detail::silence_msvc_c4127(__VA_ARGS__)
-
-#else
-#    define PYBIND11_SILENCE_MSVC_C4127(...) __VA_ARGS__
-#endif
-
 #if defined(__clang__)                                                                            \
     && (defined(__apple_build_version__) /* AppleClang 13.0.0.13000029 was the only data point    \
                                             available. */                                         \

include/pybind11/detail/init.h

@@ -12,6 +12,9 @@
 #include "class.h"
 
 PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+
+PYBIND11_WARNING_DISABLE_MSVC(4127)
+
 PYBIND11_NAMESPACE_BEGIN(detail)
 
 template <>
@@ -115,7 +118,7 @@ template <typename Class>
 void construct(value_and_holder &v_h, Cpp<Class> *ptr, bool need_alias) {
     PYBIND11_WORKAROUND_INCORRECT_MSVC_C4100(need_alias);
     no_nullptr(ptr);
-    if (PYBIND11_SILENCE_MSVC_C4127(Class::has_alias) && need_alias && !is_alias<Class>(ptr)) {
+    if (Class::has_alias && need_alias && !is_alias<Class>(ptr)) {
         // We're going to try to construct an alias by moving the cpp type.  Whether or not
         // that succeeds, we still need to destroy the original cpp pointer (either the
         // moved away leftover, if the alias construction works, or the value itself if we
@@ -156,7 +159,7 @@ void construct(value_and_holder &v_h, Holder<Class> holder, bool need_alias) {
     auto *ptr = holder_helper<Holder<Class>>::get(holder);
     no_nullptr(ptr);
     // If we need an alias, check that the held pointer is actually an alias instance
-    if (PYBIND11_SILENCE_MSVC_C4127(Class::has_alias) && need_alias && !is_alias<Class>(ptr)) {
+    if (Class::has_alias && need_alias && !is_alias<Class>(ptr)) {
         throw type_error("pybind11::init(): construction failed: returned holder-wrapped instance "
                          "is not an alias instance");
     }
@@ -174,7 +177,7 @@ void construct(value_and_holder &v_h, Cpp<Class> &&result, bool need_alias) {
     PYBIND11_WORKAROUND_INCORRECT_MSVC_C4100(need_alias);
     static_assert(std::is_move_constructible<Cpp<Class>>::value,
                   "pybind11::init() return-by-value factory function requires a movable class");
-    if (PYBIND11_SILENCE_MSVC_C4127(Class::has_alias) && need_alias) {
+    if (Class::has_alias && need_alias) {
         construct_alias_from_cpp<Class>(is_alias_constructible<Class>{}, v_h, std::move(result));
     } else {
         v_h.value_ptr() = new Cpp<Class>(std::move(result));
@@ -206,10 +209,11 @@ struct constructor {
             extra...);
     }
 
-    template <typename Class,
+    template <
+        typename Class,
         typename... Extra,
-              enable_if_t<Class::has_alias && std::is_constructible<Cpp<Class>, Args...>::value,
-                          int> = 0>
+        enable_if_t<Class::has_alias && std::is_constructible<Cpp<Class>, Args...>::value, int>
+        = 0>
     static void execute(Class &cl, const Extra &...extra) {
         cl.def(
             "__init__",
@@ -226,10 +230,11 @@ struct constructor {
             extra...);
     }
 
-    template <typename Class,
+    template <
+        typename Class,
         typename... Extra,
-              enable_if_t<Class::has_alias && !std::is_constructible<Cpp<Class>, Args...>::value,
-                          int> = 0>
+        enable_if_t<Class::has_alias && !std::is_constructible<Cpp<Class>, Args...>::value, int>
+        = 0>
     static void execute(Class &cl, const Extra &...extra) {
         cl.def(
             "__init__",
@@ -245,10 +250,11 @@ struct constructor {
 // Implementing class for py::init_alias<...>()
 template <typename... Args>
 struct alias_constructor {
-    template <typename Class,
+    template <
+        typename Class,
         typename... Extra,
-              enable_if_t<Class::has_alias && std::is_constructible<Alias<Class>, Args...>::value,
-                          int> = 0>
+        enable_if_t<Class::has_alias && std::is_constructible<Alias<Class>, Args...>::value, int>
+        = 0>
     static void execute(Class &cl, const Extra &...extra) {
         cl.def(
             "__init__",

include/pybind11/detail/internals.h

@@ -43,6 +43,8 @@ using ExceptionTranslator = void (*)(std::exception_ptr);
 
 PYBIND11_NAMESPACE_BEGIN(detail)
 
+constexpr const char *internals_function_record_capsule_name = "pybind11_function_record_capsule";
+
 // Forward declarations
 inline PyTypeObject *make_static_property_type();
 inline PyTypeObject *make_default_metaclass();
@@ -182,6 +184,16 @@ struct internals {
 #    endif // PYBIND11_INTERNALS_VERSION > 4
     // Unused if PYBIND11_SIMPLE_GIL_MANAGEMENT is defined:
     PyInterpreterState *istate = nullptr;
+
+#    if PYBIND11_INTERNALS_VERSION > 4
+    // Note that we have to use a std::string to allocate memory to ensure a unique address
+    // We want unique addresses since we use pointer equality to compare function records
+    std::string function_record_capsule_name = internals_function_record_capsule_name;
+#    endif
+
+    internals() = default;
+    internals(const internals &other) = delete;
+    internals &operator=(const internals &other) = delete;
     ~internals() {
 #    if PYBIND11_INTERNALS_VERSION > 4
         PYBIND11_TLS_FREE(loader_life_support_tls_key);
@@ -456,9 +468,6 @@ PYBIND11_NOINLINE internals &get_internals() {
         internals_ptr = new internals();
 #if defined(WITH_THREAD)
 
-#    if PY_VERSION_HEX < 0x03090000
-        PyEval_InitThreads();
-#    endif
         PyThreadState *tstate = PyThreadState_Get();
         if (!PYBIND11_TLS_KEY_CREATE(internals_ptr->tstate)) {
             pybind11_fail("get_internals: could not successfully initialize the tstate TSS key!");
@@ -548,6 +557,25 @@ const char *c_str(Args &&...args) {
     return strings.front().c_str();
 }
 
+inline const char *get_function_record_capsule_name() {
+#if PYBIND11_INTERNALS_VERSION > 4
+    return get_internals().function_record_capsule_name.c_str();
+#else
+    return nullptr;
+#endif
+}
+
+// Determine whether or not the following capsule contains a pybind11 function record.
+// Note that we use `internals` to make sure that only ABI compatible records are touched.
+//
+// This check is currently used in two places:
+// - An important optimization in functional.h to avoid overhead in C++ -> Python -> C++
+// - The sibling feature of cpp_function to allow overloads
+inline bool is_function_record_capsule(const capsule &cap) {
+    // Pointer equality as we rely on internals() to ensure unique pointers
+    return cap.name() == get_function_record_capsule_name();
+}
+
 PYBIND11_NAMESPACE_END(detail)
 
 /// Returns a named pointer that is shared among all extension modules (using the same

include/pybind11/detail/type_caster_base.h

@@ -1006,5 +1006,14 @@ protected:
     static Constructor make_move_constructor(...) { return nullptr; }
 };
 
+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());
+}
+
 PYBIND11_NAMESPACE_END(detail)
 PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)