[smart_holder] Curated git merge master after clang-format etc

.appveyor.yml

@@ -1,6 +1,6 @@
 version: 1.0.{build}
 image:
-- Visual Studio 2015
+- Visual Studio 2017
 test: off
 skip_branch_with_pr: true
 build:
@@ -11,11 +11,9 @@ environment:
   matrix:
   - PYTHON: 36
     CONFIG: Debug
-  - PYTHON: 27
-    CONFIG: Debug
 install:
 - ps: |
-    $env:CMAKE_GENERATOR = "Visual Studio 14 2015"
+    $env:CMAKE_GENERATOR = "Visual Studio 15 2017"
     if ($env:PLATFORM -eq "x64") { $env:PYTHON = "$env:PYTHON-x64" }
     $env:PATH = "C:\Python$env:PYTHON\;C:\Python$env:PYTHON\Scripts\;$env:PATH"
     python -W ignore -m pip install --upgrade pip wheel

.clang-format

@@ -3,17 +3,36 @@
 # clang-format --style=llvm --dump-config
 BasedOnStyle: LLVM
 AccessModifierOffset: -4
+AllowShortLambdasOnASingleLine: true
 AlwaysBreakTemplateDeclarations: Yes
 BinPackArguments: false
 BinPackParameters: false
 BreakBeforeBinaryOperators: All
 BreakConstructorInitializers: BeforeColon
 ColumnLimit: 99
+CommentPragmas: 'NOLINT:.*|^ IWYU pragma:'
+IncludeBlocks: Regroup
 IndentCaseLabels: true
 IndentPPDirectives: AfterHash
 IndentWidth: 4
 Language: Cpp
 SpaceAfterCStyleCast: true
 Standard: Cpp11
+StatementMacros: ['PyObject_HEAD']
 TabWidth: 4
+IncludeCategories:
+  - Regex:           '<pybind11/.*'
+    Priority:        -1
+  - Regex:           'pybind11.h"$'
+    Priority:        1
+  - Regex:           '^".*/?detail/'
+    Priority:        1
+    SortPriority:    2
+  - Regex:           '^"'
+    Priority:        1
+    SortPriority:    3
+  - Regex:           '<[[:alnum:]._]+>'
+    Priority:        4
+  - Regex:           '.*'
+    Priority:        5
 ...

.clang-tidy

@@ -2,9 +2,12 @@ FormatStyle: file
 
 Checks: '
 *bugprone*,
+clang-analyzer-optin.performance.Padding,
+clang-analyzer-optin.cplusplus.VirtualCall,
 cppcoreguidelines-init-variables,
+cppcoreguidelines-prefer-member-initializer,
+cppcoreguidelines-pro-type-static-cast-downcast,
 cppcoreguidelines-slicing,
-clang-analyzer-optin.cplusplus.VirtualCall,
 google-explicit-constructor,
 llvm-namespace-comment,
 misc-misplaced-const,
@@ -31,14 +34,17 @@ modernize-use-override,
 modernize-use-using,
 *performance*,
 readability-avoid-const-params-in-decls,
+readability-braces-around-statements,
 readability-const-return-type,
 readability-container-size-empty,
 readability-delete-null-pointer,
 readability-else-after-return,
 readability-implicit-bool-conversion,
+readability-inconsistent-declaration-parameter-name,
 readability-make-member-function-const,
 readability-misplaced-array-index,
 readability-non-const-parameter,
+readability-qualified-auto,
 readability-redundant-function-ptr-dereference,
 readability-redundant-smartptr-get,
 readability-redundant-string-cstr,

.github/CONTRIBUTING.md

@@ -93,19 +93,18 @@ cmake --build build -j4
 
 Tips:
 
-* You can use `virtualenv` (from PyPI) instead of `venv` (which is Python 3
-  only).
+* You can use `virtualenv` (faster, from PyPI) instead of `venv`.
 * You can select any name for your environment folder; if it contains "env" it
   will be ignored by git.
-* If you don’t have CMake 3.14+, just add “cmake” to the pip install command.
+* If you don't have CMake 3.14+, just add "cmake" to the pip install command.
 * You can use `-DPYBIND11_FINDPYTHON=ON` to use FindPython on CMake 3.12+
 * In classic mode, you may need to set `-DPYTHON_EXECUTABLE=/path/to/python`.
   FindPython uses `-DPython_ROOT_DIR=/path/to` or
   `-DPython_EXECUTABLE=/path/to/python`.
 
 ### Configuration options
 
-In CMake, configuration options are given with “-D”. Options are stored in the
+In CMake, configuration options are given with "-D". Options are stored in the
 build directory, in the `CMakeCache.txt` file, so they are remembered for each
 build directory. Two selections are special - the generator, given with `-G`,
 and the compiler, which is selected based on environment variables `CXX` and
@@ -115,7 +114,7 @@ after the initial run.
 The valid options are:
 
 * `-DCMAKE_BUILD_TYPE`: Release, Debug, MinSizeRel, RelWithDebInfo
-* `-DPYBIND11_FINDPYTHON=ON`: Use CMake 3.12+’s FindPython instead of the
+* `-DPYBIND11_FINDPYTHON=ON`: Use CMake 3.12+'s FindPython instead of the
   classic, deprecated, custom FindPythonLibs
 * `-DPYBIND11_NOPYTHON=ON`: Disable all Python searching (disables tests)
 * `-DBUILD_TESTING=ON`: Enable the tests
@@ -257,7 +256,7 @@ The report is sent to stderr; you can pipe it into a file if you wish.
 ### Build recipes
 
 This builds with the Intel compiler (assuming it is in your path, along with a
-recent CMake and Python 3):
+recent CMake and Python):
 
 ```bash
 python3 -m venv venv

.github/workflows/ci.yml

@@ -16,6 +16,8 @@ concurrency:
 
 env:
   PIP_ONLY_BINARY: numpy
+  FORCE_COLOR: 3
+  PYTEST_TIMEOUT: 300
 
 jobs:
   # This is the "main" test suite, which tests a large number of different
@@ -26,8 +28,6 @@ jobs:
       matrix:
         runs-on: [ubuntu-latest, windows-2022, macos-latest]
         python:
-        - '2.7'
-        - '3.5'
         - '3.6'
         - '3.9'
         - '3.10'
@@ -45,18 +45,14 @@ jobs:
             python: '3.6'
             args: >
               -DPYBIND11_FINDPYTHON=ON
-              -DCMAKE_CXX_FLAGS="-D_=1"
+# BREAKS      -DCMAKE_CXX_FLAGS="-D_=1"
           - runs-on: windows-latest
             python: '3.6'
             args: >
               -DPYBIND11_FINDPYTHON=ON
-          - runs-on: macos-latest
-            python: 'pypy-2.7'
           # Inject a couple Windows 2019 runs
           - runs-on: windows-2019
             python: '3.9'
-          - runs-on: windows-2019
-            python: '2.7'
 
     name: "🐍 ${{ matrix.python }} • ${{ matrix.runs-on }} • x64 ${{ matrix.args }}"
     runs-on: ${{ matrix.runs-on }}
@@ -169,27 +165,11 @@ jobs:
     - name: Interface test
       run: cmake --build build2 --target test_cmake_build
 
-    # Eventually Microsoft might have an action for setting up
-    # MSVC, but for now, this action works:
-    - name: Prepare compiler environment for Windows 🐍 2.7
-      if: matrix.python == 2.7 && runner.os == 'Windows'
-      uses: ilammy/msvc-dev-cmd@v1.10.0
-      with:
-        arch: x64
-
-    # This makes two environment variables available in the following step(s)
-    - name: Set Windows 🐍 2.7 environment variables
-      if: matrix.python == 2.7 && runner.os == 'Windows'
-      shell: bash
-      run: |
-        echo "DISTUTILS_USE_SDK=1" >> $GITHUB_ENV
-        echo "MSSdk=1" >> $GITHUB_ENV
-
     # This makes sure the setup_helpers module can build packages using
     # setuptools
     - name: Setuptools helpers test
       run: pytest tests/extra_setuptools
-      if: "!(matrix.python == '3.5' && matrix.runs-on == 'windows-2022')"
+      if: "!(matrix.runs-on == 'windows-2022')"
 
 
   deadsnakes:
@@ -646,9 +626,9 @@ jobs:
 
   # This tests an "install" with the CMake tools
   install-classic:
-    name: "🐍 3.5 • Debian • x86 •  Install"
+    name: "🐍 3.7 • Debian • x86 •  Install"
     runs-on: ubuntu-latest
-    container: i386/debian:stretch
+    container: i386/debian:buster
 
     steps:
     - uses: actions/checkout@v1
@@ -657,7 +637,7 @@ jobs:
       run: |
         apt-get update
         apt-get install -y git make cmake g++ libeigen3-dev python3-dev python3-pip
-        pip3 install "pytest==3.1.*"
+        pip3 install "pytest==6.*"
 
     - name: Configure for install
       run: >
@@ -726,12 +706,10 @@ jobs:
       fail-fast: false
       matrix:
         python:
-        - 3.5
         - 3.6
         - 3.7
         - 3.8
         - 3.9
-        - pypy-3.6
 
         include:
           - python: 3.9
@@ -778,17 +756,23 @@ jobs:
     - name: Python tests
       run: cmake --build build -t pytest
 
-  win32-msvc2015:
-    name: "🐍 ${{ matrix.python }} • MSVC 2015 • x64"
-    runs-on: windows-latest
+  win32-msvc2017:
+    name: "🐍 ${{ matrix.python }} • MSVC 2017 • x64"
+    runs-on: windows-2016
     strategy:
       fail-fast: false
       matrix:
         python:
-          - 2.7
           - 3.6
           - 3.7
-          # todo: check/cpptest does not support 3.8+ yet
+        std:
+          - 14
+
+        include:
+          - python: 3.7
+            std: 17
+            args: >
+              -DCMAKE_CXX_FLAGS="/permissive- /EHsc /GR"
 
     steps:
     - uses: actions/checkout@v2
@@ -801,11 +785,6 @@ jobs:
     - name: Update CMake
       uses: jwlawson/actions-setup-cmake@v1.12
 
-    - name: Prepare MSVC
-      uses: ilammy/msvc-dev-cmd@v1.10.0
-      with:
-        toolset: 14.0
-
     - name: Prepare env
       run: |
         python -m pip install -r tests/requirements.txt
@@ -814,72 +793,63 @@ jobs:
     - name: Configure
       run: >
         cmake -S . -B build
-        -G "Visual Studio 14 2015" -A x64
+        -G "Visual Studio 15 2017" -A x64
         -DPYBIND11_WERROR=ON
         -DDOWNLOAD_CATCH=ON
         -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
+        ${{ matrix.args }}
 
-    - name: Build C++14
+    - name: Build ${{ matrix.std }}
       run: cmake --build build -j 2
 
     - name: Run all checks
       run: cmake --build build -t check
 
-
-  win32-msvc2017:
-    name: "🐍 ${{ matrix.python }} • MSVC 2017 • x64"
-    runs-on: windows-2016
+  windows-2022:
     strategy:
       fail-fast: false
       matrix:
         python:
-          - 2.7
-          - 3.5
-          - 3.7
-        std:
-          - 14
+        - 3.9
 
-        include:
-          - python: 2.7
-            std: 17
-            args: >
-              -DCMAKE_CXX_FLAGS="/permissive- /EHsc /GR"
-          - python: 3.7
-            std: 17
-            args: >
-              -DCMAKE_CXX_FLAGS="/permissive- /EHsc /GR"
+    name: "🐍 ${{ matrix.python }} • MSVC 2022 C++20 • x64"
+    runs-on: windows-2022
 
     steps:
     - uses: actions/checkout@v2
 
-    - name: Setup 🐍 ${{ matrix.python }}
+    - name: Setup Python ${{ matrix.python }}
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python }}
 
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v1.12
-
     - name: Prepare env
       run: |
-        python -m pip install -r tests/requirements.txt
+        python3 -m pip install -r tests/requirements.txt
 
-    # First build - C++11 mode and inplace
-    - name: Configure
+    - name: Update CMake
+      uses: jwlawson/actions-setup-cmake@v1.12
+
+    - name: Configure C++20
       run: >
         cmake -S . -B build
-        -G "Visual Studio 15 2017" -A x64
         -DPYBIND11_WERROR=ON
         -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
-        ${{ matrix.args }}
+        -DDOWNLOAD_EIGEN=OFF
+        -DCMAKE_CXX_STANDARD=20
 
-    - name: Build ${{ matrix.std }}
+    - name: Build C++20
       run: cmake --build build -j 2
 
-    - name: Run all checks
-      run: cmake --build build -t check
+    - name: Python tests
+      run: cmake --build build --target pytest
+
+    - name: C++20 tests
+      run: cmake --build build --target cpptest -j 2
+
+    - name: Interface test C++20
+      run: cmake --build build --target test_cmake_build
 
   mingw:
     name: "🐍 3 • windows-latest • ${{ matrix.sys }}"
@@ -915,7 +885,7 @@ 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 -S . -B build
+      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=11 -DDOWNLOAD_CATCH=ON -S . -B build
 
     - name: Build C++11
       run: cmake --build build -j 2
@@ -933,7 +903,7 @@ jobs:
       run: git clean -fdx
 
     - name: Configure C++14
-      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=14 -S . -B build2
+      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=14 -DDOWNLOAD_CATCH=ON -S . -B build2
 
     - name: Build C++14
       run: cmake --build build2 -j 2
@@ -951,7 +921,7 @@ jobs:
       run: git clean -fdx
 
     - name: Configure C++17
-      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=17 -S . -B build3
+      run: cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=17 -DDOWNLOAD_CATCH=ON -S . -B build3
 
     - name: Build C++17
       run: cmake --build build3 -j 2