Merge branch 'master' into stable

.github/workflows/ci.yml

@@ -9,6 +9,13 @@ on:
       - stable
       - v*
 
+concurrency:
+  group: test-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  PIP_ONLY_BINARY: numpy
+
 jobs:
   # This is the "main" test suite, which tests a large number of different
   # versions of default compilers and Python versions in GitHub Actions.
@@ -18,13 +25,14 @@ jobs:
       matrix:
         runs-on: [ubuntu-latest, windows-latest, macos-latest]
         python:
-        - 2.7
-        - 3.5
-        - 3.6
-        - 3.9
-        - 3.10-dev
-        - pypy2
-        - pypy3
+        - '2.7'
+        - '3.5'
+        - '3.6'
+        - '3.9'
+        - '3.10'
+        # - '3.11-dev'
+        - 'pypy-3.7-v7.3.5'
+        # - 'pypy-3.8'
 
         # Items in here will either be added to the build matrix (if not
         # present), or add new keys to an existing matrix element if all the
@@ -42,18 +50,8 @@ jobs:
             python: 3.6
             args: >
               -DPYBIND11_FINDPYTHON=ON
-
-        # These items will be removed from the build matrix, keys must match.
-        exclude:
-            # Currently 32bit only, and we build 64bit
-          - runs-on: windows-latest
-            python: pypy2
-          - runs-on: windows-latest
-            python: pypy3
-
-          # TODO: PyPy2 7.3.3 segfaults, while 7.3.2 was fine.
-          - runs-on: ubuntu-latest
-            python: pypy2
+          - runs-on: macos-latest
+            python: pypy-2.7
 
     name: "🐍 ${{ matrix.python }} • ${{ matrix.runs-on }} • x64 ${{ matrix.args }}"
     runs-on: ${{ matrix.runs-on }}
@@ -89,7 +87,8 @@ jobs:
         key: ${{ runner.os }}-pip-${{ matrix.python }}-x64-${{ hashFiles('tests/requirements.txt') }}
 
     - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
+      run: |
+        python -m pip install -r tests/requirements.txt
 
     - name: Setup annotations on Linux
       if: runner.os == 'Linux'
@@ -113,7 +112,7 @@ jobs:
 
     - name: C++11 tests
       # TODO: Figure out how to load the DLL on Python 3.8+
-      if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10-dev'))"
+      if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10' || matrix.python == '3.11-dev' || matrix.python == 'pypy-3.8'))"
       run: cmake --build .  --target cpptest -j 2
 
     - name: Interface test C++11
@@ -141,7 +140,7 @@ jobs:
 
     - name: C++ tests
       # TODO: Figure out how to load the DLL on Python 3.8+
-      if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10-dev'))"
+      if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10' || matrix.python == '3.11-dev' || matrix.python == 'pypy-3.8'))"
       run: cmake --build build2 --target cpptest
 
     # Third build - C++17 mode with unstable ABI
@@ -169,7 +168,7 @@ jobs:
     # 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@v1.9.0
+      uses: ilammy/msvc-dev-cmd@v1.10.0
       with:
         arch: x64
 
@@ -192,11 +191,12 @@ jobs:
       fail-fast: false
       matrix:
         include:
-        - python-version: 3.9
+        # TODO: Fails on 3.10, investigate
+        - python-version: "3.9"
           python-debug: true
           valgrind: true
-        - python-version: 3.10-dev
-          python-debug: false
+      # - python-version: "3.11-dev"
+      #   python-debug: false
 
     name: "🐍 ${{ matrix.python-version }}${{ matrix.python-debug && '-dbg' || '' }} (deadsnakes)${{ matrix.valgrind && ' • Valgrind' || '' }} • x64"
     runs-on: ubuntu-latest
@@ -240,7 +240,8 @@ jobs:
         sudo apt-get install libc6-dbg  # Needed by Valgrind
 
     - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
+      run: |
+        python -m pip install -r tests/requirements.txt
 
     - name: Configure
       run: >
@@ -517,7 +518,7 @@ jobs:
     - name: Install dependencies
       run: |
         set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        python3 -m pip install -r tests/requirements.txt --prefer-binary
+        python3 -m pip install -r tests/requirements.txt
 
     - name: Configure C++11
       run: |
@@ -608,7 +609,8 @@ jobs:
       run: python3 -m pip install --upgrade pip
 
     - name: Install dependencies
-      run: python3 -m pip install cmake -r tests/requirements.txt --prefer-binary
+      run: |
+        python3 -m pip install cmake -r tests/requirements.txt
 
     - name: VAR_BUILD_TYPE 7
       if: matrix.centos == 7
@@ -735,8 +737,7 @@ jobs:
         - 3.7
         - 3.8
         - 3.9
-        - pypy3
-        # TODO: fix hang on pypy2
+        - pypy-3.6
 
         include:
           - python: 3.9
@@ -760,12 +761,13 @@ jobs:
       uses: jwlawson/actions-setup-cmake@v1.11
 
     - name: Prepare MSVC
-      uses: ilammy/msvc-dev-cmd@v1.9.0
+      uses: ilammy/msvc-dev-cmd@v1.10.0
       with:
         arch: x86
 
     - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
+      run: |
+        python -m pip install -r tests/requirements.txt
 
     # First build - C++11 mode and inplace
     - name: Configure ${{ matrix.args }}
@@ -806,12 +808,13 @@ jobs:
       uses: jwlawson/actions-setup-cmake@v1.11
 
     - name: Prepare MSVC
-      uses: ilammy/msvc-dev-cmd@v1.9.0
+      uses: ilammy/msvc-dev-cmd@v1.10.0
       with:
         toolset: 14.0
 
     - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
+      run: |
+        python -m pip install -r tests/requirements.txt
 
     # First build - C++11 mode and inplace
     - name: Configure
@@ -847,6 +850,10 @@ jobs:
             std: 17
             args: >
               -DCMAKE_CXX_FLAGS="/permissive- /EHsc /GR"
+          - python: 3.7
+            std: 17
+            args: >
+              -DCMAKE_CXX_FLAGS="/permissive- /EHsc /GR"
 
     steps:
     - uses: actions/checkout@v2
@@ -860,7 +867,8 @@ jobs:
       uses: jwlawson/actions-setup-cmake@v1.11
 
     - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
+      run: |
+        python -m pip install -r tests/requirements.txt
 
     # First build - C++11 mode and inplace
     - name: Configure
@@ -892,7 +900,8 @@ jobs:
           - { sys: mingw64, env: x86_64 }
           - { sys: mingw32, env: i686 }
     steps:
-    - uses: msys2/setup-msys2@v2
+    # Force version because of https://github.com/msys2/setup-msys2/issues/167
+    - uses: msys2/setup-msys2@v2.4.2
       with:
         msystem: ${{matrix.sys}}
         install: >-

.github/workflows/pip.yml

@@ -12,6 +12,9 @@ on:
     types:
     - published
 
+env:
+  PIP_ONLY_BINARY: numpy
+
 jobs:
   # This builds the sdists and wheels and makes sure the files are exactly as
   # expected. Using Windows and Python 2.7, since that is often the most
@@ -29,7 +32,8 @@ jobs:
         python-version: 2.7
 
     - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
+      run: |
+        python -m pip install -r tests/requirements.txt
 
     - name: Python Packaging tests
       run: pytest tests/extra_python_package/
@@ -50,7 +54,8 @@ jobs:
         python-version: 3.8
 
     - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt build twine --prefer-binary
+      run: |
+        python -m pip install -r tests/requirements.txt build twine
 
     - name: Python Packaging tests
       run: pytest tests/extra_python_package/

.pre-commit-config.yaml

@@ -61,20 +61,32 @@ repos:
   hooks:
   - id: remove-tabs
 
-# Autoremoves unused imports
-- repo: https://github.com/hadialqattan/pycln
-  rev: v1.0.3
+- repo: https://github.com/pre-commit/pygrep-hooks
+  rev: v1.9.0
   hooks:
-  - id: pycln
+  - id: python-check-blanket-noqa
+  - id: python-check-blanket-type-ignore
+  - id: python-no-log-warn
+  - id: rst-backticks
+  - id: rst-directive-colons
+  - id: rst-inline-touching-normal
 
 # Flake8 also supports pre-commit natively (same author)
 - repo: https://github.com/PyCQA/flake8
-  rev: 3.9.2
+  rev: 4.0.1
   hooks:
   - id: flake8
-    additional_dependencies: [flake8-bugbear, pep8-naming]
+    additional_dependencies: &flake8_dependencies
+      - flake8-bugbear
+      - pep8-naming
     exclude: ^(docs/.*|tools/.*)$
 
+- repo: https://github.com/asottile/yesqa
+  rev: v1.3.0
+  hooks:
+  - id: yesqa
+    additional_dependencies: *flake8_dependencies
+
 # CMake formatting
 - repo: https://github.com/cheshirekow/cmake-format-precommit
   rev: v0.6.13
@@ -86,12 +98,9 @@ repos:
 
 # Check static types with mypy
 - repo: https://github.com/pre-commit/mirrors-mypy
-  rev: v0.910
+  rev: v0.910-1
   hooks:
   - id: mypy
-    # The default Python type ignores .pyi files, so let's rerun if detected
-    types: [text]
-    files: ^pybind11.*\.pyi?$
     # Running per-file misbehaves a bit, so just run on all files, it's fast
     pass_filenames: false
     additional_dependencies: [typed_ast]

CMakeLists.txt

@@ -7,13 +7,13 @@
 
 cmake_minimum_required(VERSION 3.4)
 
-# The `cmake_minimum_required(VERSION 3.4...3.21)` syntax does not work with
+# The `cmake_minimum_required(VERSION 3.4...3.22)` syntax does not work with
 # some versions of VS that have a patched CMake 3.11. This forces us to emulate
 # the behavior using the following workaround:
-if(${CMAKE_VERSION} VERSION_LESS 3.21)
+if(${CMAKE_VERSION} VERSION_LESS 3.22)
   cmake_policy(VERSION ${CMAKE_MAJOR_VERSION}.${CMAKE_MINOR_VERSION})
 else()
-  cmake_policy(VERSION 3.21)
+  cmake_policy(VERSION 3.22)
 endif()
 
 # Extract project version from source

docs/advanced/classes.rst

@@ -1266,7 +1266,7 @@ Custom type setup
 =================
 
 For advanced use cases, such as enabling garbage collection support, you may
-wish to directly manipulate the `PyHeapTypeObject` corresponding to a
+wish to directly manipulate the ``PyHeapTypeObject`` corresponding to a
 ``py::class_`` definition.
 
 You can do that using ``py::custom_type_setup``:

docs/advanced/embedding.rst

@@ -40,15 +40,15 @@ The essential structure of the ``main.cpp`` file looks like this:
     }
 
 The interpreter must be initialized before using any Python API, which includes
-all the functions and classes in pybind11. The RAII guard class `scoped_interpreter`
+all the functions and classes in pybind11. The RAII guard class ``scoped_interpreter``
 takes care of the interpreter lifetime. After the guard is destroyed, the interpreter
 shuts down and clears its memory. No Python functions can be called after this.
 
 Executing Python code
 =====================
 
-There are a few different ways to run Python code. One option is to use `eval`,
-`exec` or `eval_file`, as explained in :ref:`eval`. Here is a quick example in
+There are a few different ways to run Python code. One option is to use ``eval``,
+``exec`` or ``eval_file``, as explained in :ref:`eval`. Here is a quick example in
 the context of an executable with an embedded interpreter:
 
 .. code-block:: cpp
@@ -108,7 +108,7 @@ The two approaches can also be combined:
 Importing modules
 =================
 
-Python modules can be imported using `module_::import()`:
+Python modules can be imported using ``module_::import()``:
 
 .. code-block:: cpp
 
@@ -134,7 +134,7 @@ embedding the interpreter. This makes it easy to import local Python files:
     int n = result.cast<int>();
     assert(n == 3);
 
-Modules can be reloaded using `module_::reload()` if the source is modified e.g.
+Modules can be reloaded using ``module_::reload()`` if the source is modified e.g.
 by an external process. This can be useful in scenarios where the application
 imports a user defined data processing script which needs to be updated after
 changes by the user. Note that this function does not reload modules recursively.
@@ -144,7 +144,7 @@ changes by the user. Note that this function does not reload modules recursively
 Adding embedded modules
 =======================
 
-Embedded binary modules can be added using the `PYBIND11_EMBEDDED_MODULE` macro.
+Embedded binary modules can be added using the ``PYBIND11_EMBEDDED_MODULE`` macro.
 Note that the definition must be placed at global scope. They can be imported
 like any other module.
 
@@ -170,7 +170,7 @@ like any other module.
 
 Unlike extension modules where only a single binary module can be created, on
 the embedded side an unlimited number of modules can be added using multiple
-`PYBIND11_EMBEDDED_MODULE` definitions (as long as they have unique names).
+``PYBIND11_EMBEDDED_MODULE`` definitions (as long as they have unique names).
 
 These modules are added to Python's list of builtins, so they can also be
 imported in pure Python files loaded by the interpreter. Everything interacts
@@ -216,9 +216,9 @@ naturally:
 Interpreter lifetime
 ====================
 
-The Python interpreter shuts down when `scoped_interpreter` is destroyed. After
+The Python interpreter shuts down when ``scoped_interpreter`` is destroyed. After
 this, creating a new instance will restart the interpreter. Alternatively, the
-`initialize_interpreter` / `finalize_interpreter` pair of functions can be used
+``initialize_interpreter`` / ``finalize_interpreter`` pair of functions can be used
 to directly set the state at any time.
 
 Modules created with pybind11 can be safely re-initialized after the interpreter
@@ -230,8 +230,8 @@ global data. All the details can be found in the CPython documentation.
 
 .. warning::
 
-    Creating two concurrent `scoped_interpreter` guards is a fatal error. So is
-    calling `initialize_interpreter` for a second time after the interpreter
+    Creating two concurrent ``scoped_interpreter`` guards is a fatal error. So is
+    calling ``initialize_interpreter`` for a second time after the interpreter
     has already been initialized.
 
     Do not use the raw CPython API functions ``Py_Initialize`` and
@@ -242,7 +242,7 @@ global data. All the details can be found in the CPython documentation.
 Sub-interpreter support
 =======================
 
-Creating multiple copies of `scoped_interpreter` is not possible because it
+Creating multiple copies of ``scoped_interpreter`` is not possible because it
 represents the main Python interpreter. Sub-interpreters are something different
 and they do permit the existence of multiple interpreters. This is an advanced
 feature of the CPython API and should be handled with care. pybind11 does not
@@ -258,5 +258,5 @@ We'll just mention a couple of caveats the sub-interpreters support in pybind11:
  2. Managing multiple threads, multiple interpreters and the GIL can be
     challenging and there are several caveats here, even within the pure
     CPython API (please refer to the Python docs for details). As for
-    pybind11, keep in mind that `gil_scoped_release` and `gil_scoped_acquire`
+    pybind11, keep in mind that ``gil_scoped_release`` and ``gil_scoped_acquire``
     do not take sub-interpreters into account.

docs/advanced/exceptions.rst

@@ -56,7 +56,9 @@ at its exception handler.
 +--------------------------------------+--------------------------------------+
 | :class:`pybind11::buffer_error`      | ``BufferError``                      |
 +--------------------------------------+--------------------------------------+
-| :class:`pybind11::import_error`      | ``import_error``                     |
+| :class:`pybind11::import_error`      | ``ImportError``                      |
++--------------------------------------+--------------------------------------+
+| :class:`pybind11::attribute_error`   | ``AttributeError``                   |
 +--------------------------------------+--------------------------------------+
 | Any other exception                  | ``RuntimeError``                     |
 +--------------------------------------+--------------------------------------+
@@ -96,18 +98,18 @@ A matching function is available for registering a local exception translator:
 
 
 It is possible to specify base class for the exception using the third
-parameter, a `handle`:
+parameter, a ``handle``:
 
 .. code-block:: cpp
 
     py::register_exception<CppExp>(module, "PyExp", PyExc_RuntimeError);
     py::register_local_exception<CppExp>(module, "PyExp", PyExc_RuntimeError);
 
-Then `PyExp` can be caught both as `PyExp` and `RuntimeError`.
+Then ``PyExp`` can be caught both as ``PyExp`` and ``RuntimeError``.
 
 The class objects of the built-in Python exceptions are listed in the Python
 documentation on `Standard Exceptions <https://docs.python.org/3/c-api/exceptions.html#standard-exceptions>`_.
-The default base class is `PyExc_Exception`.
+The default base class is ``PyExc_Exception``.
 
 When more advanced exception translation is needed, the functions
 ``py::register_exception_translator(translator)`` and

docs/advanced/functions.rst

@@ -232,7 +232,7 @@ is equivalent to the following pseudocode:
     });
 
 The only requirement is that ``T`` is default-constructible, but otherwise any
-scope guard will work. This is very useful in combination with `gil_scoped_release`.
+scope guard will work. This is very useful in combination with ``gil_scoped_release``.
 See :ref:`gil`.
 
 Multiple guards can also be specified as ``py::call_guard<T1, T2, T3...>``. The

docs/advanced/misc.rst

@@ -84,7 +84,7 @@ could be realized as follows (important changes highlighted):
         });
     }
 
-The ``call_go`` wrapper can also be simplified using the `call_guard` policy
+The ``call_go`` wrapper can also be simplified using the ``call_guard`` policy
 (see :ref:`call_policies`) which yields the same result:
 
 .. code-block:: cpp

docs/advanced/pycpp/object.rst

@@ -41,24 +41,17 @@ A tuple of python objects can be instantiated using :func:`py::make_tuple`:
 Each element is converted to a supported Python type.
 
 A `simple namespace`_ can be instantiated using
-:func:`py::make_simple_namespace`:
 
 .. code-block:: cpp
 
-    using namespace pybind11::literals; // to bring in the `_a` literal
-    py::object ns = py::make_simple_namespace("spam"_a=py::none(), "eggs"_a=42);
+    using namespace pybind11::literals;  // to bring in the `_a` literal
+    py::object SimpleNamespace = py::module_::import("types").attr("SimpleNamespace");
+    py::object ns = SimpleNamespace("spam"_a=py::none(), "eggs"_a=42);
 
 Attributes on a namespace can be modified with the :func:`py::delattr`,
 :func:`py::getattr`, and :func:`py::setattr` functions. Simple namespaces can
 be useful as lightweight stand-ins for class instances.
 
-.. note::
-
-    ``make_simple_namespace`` is not available in Python 2.
-
-.. versionchanged:: 2.8
-    ``make_simple_namespace`` added.
-
 .. _simple namespace: https://docs.python.org/3/library/types.html#types.SimpleNamespace
 
 .. _casting_back_and_forth:

docs/advanced/pycpp/utilities.rst

@@ -28,7 +28,7 @@ Capturing standard output from ostream
 
 Often, a library will use the streams ``std::cout`` and ``std::cerr`` to print,
 but this does not play well with Python's standard ``sys.stdout`` and ``sys.stderr``
-redirection. Replacing a library's printing with `py::print <print>` may not
+redirection. Replacing a library's printing with ``py::print <print>`` may not
 be feasible. This can be fixed using a guard around the library function that
 redirects output to the corresponding Python streams:
 
@@ -62,9 +62,9 @@ This method respects flushes on the output streams and will flush if needed
 when the scoped guard is destroyed. This allows the output to be redirected in
 real time, such as to a Jupyter notebook. The two arguments, the C++ stream and
 the Python output, are optional, and default to standard output if not given. An
-extra type, `py::scoped_estream_redirect <scoped_estream_redirect>`, is identical
+extra type, ``py::scoped_estream_redirect <scoped_estream_redirect>``, is identical
 except for defaulting to ``std::cerr`` and ``sys.stderr``; this can be useful with
-`py::call_guard`, which allows multiple items, but uses the default constructor:
+``py::call_guard``, which allows multiple items, but uses the default constructor:
 
 .. code-block:: cpp
 
@@ -74,7 +74,7 @@ except for defaulting to ``std::cerr`` and ``sys.stderr``; this can be useful wi
                          py::scoped_estream_redirect>());
 
 The redirection can also be done in Python with the addition of a context
-manager, using the `py::add_ostream_redirect() <add_ostream_redirect>` function:
+manager, using the ``py::add_ostream_redirect() <add_ostream_redirect>`` function:
 
 .. code-block:: cpp
 
@@ -103,7 +103,7 @@ arguments to disable one of the streams if needed.
 Evaluating Python expressions from strings and files
 ====================================================
 
-pybind11 provides the `eval`, `exec` and `eval_file` functions to evaluate
+pybind11 provides the ``eval``, ``exec`` and ``eval_file`` functions to evaluate
 Python expressions and statements. The following example illustrates how they
 can be used.
 

docs/changelog.rst

@@ -6,6 +6,54 @@ Changelog
 Starting with version 1.8.0, pybind11 releases use a `semantic versioning
 <http://semver.org>`_ policy.
 
+
+IN DEVELOPMENT
+--------------
+
+v2.8.1 (Oct 27, 2021)
+---------------------
+
+Changes and additions:
+
+* The simple namespace creation shortcut added in 2.8.0 was deprecated due to
+  usage of CPython internal API, and will be removed soon. Use
+  ``py::module_::import("types").attr("SimpleNamespace")``.
+  `#3374 <https://github.com/pybinyyd/pybind11/pull/3374>`_
+
+* Add C++ Exception type to throw and catch ``AttributeError``. Useful for
+  defining custom ``__setattr__`` and ``__getattr__`` methods.
+  `#3387 <https://github.com/pybind/pybind11/pull/3387>`_
+
+Fixes:
+
+* Fixed the potential for dangling references when using properties with
+  ``std::optional`` types.
+  `#3376 <https://github.com/pybind/pybind11/pull/3376>`_
+
+* Modernize usage of ``PyCodeObject`` on Python 3.9+ (moving toward support for
+  Python 3.11a1)
+  `#3368 <https://github.com/pybind/pybind11/pull/3368>`_
+
+* A long-standing bug in ``eigen.h`` was fixed (originally PR #3343). The bug
+  was unmasked by newly added ``static_assert``'s in the Eigen 3.4.0 release.
+  `#3352 <https://github.com/pybind/pybind11/pull/3352>`_
+
+* Support multiple raw inclusion of CMake helper files (Conan.io does this for
+  multi-config generators).
+  `#3420 <https://github.com/pybind/pybind11/pull/3420>`_
+
+* Fix harmless warning on upcoming CMake 3.22.
+  `#3368 <https://github.com/pybind/pybind11/pull/3368>`_
+
+* Fix 2.8.0 regression with MSVC 2017 + C++17 mode + Python 3.
+  `#3407 <https://github.com/pybind/pybind11/pull/3407>`_
+
+* Fix 2.8.0 regression that caused undefined behavior (typically
+  segfaults) in ``make_key_iterator``/``make_value_iterator`` if dereferencing
+  the iterator returned a temporary value instead of a reference.
+  `#3348 <https://github.com/pybind/pybind11/pull/3348>`_
+
+
 v2.8.0 (Oct 4, 2021)
 --------------------
 
@@ -19,10 +67,10 @@ New features:
   ``register_local_exception_translator(ExceptionTranslator&& translator)``
   instead of  ``register_exception_translator(ExceptionTranslator&&
   translator)`` to keep your exception remapping code local to the module.
-  `#2650 <https://github.com/pybind/pybind11/pull/2650>`_
+  `#2650 <https://github.com/pybinyyd/pybind11/pull/2650>`_
 
 * Add ``make_simple_namespace`` function for instantiating Python
-  ``SimpleNamespace`` objects.
+  ``SimpleNamespace`` objects. **Deprecated in 2.8.1.**
   `#2840 <https://github.com/pybind/pybind11/pull/2840>`_
 
 * ``pybind11::scoped_interpreter`` and ``initialize_interpreter`` have new
@@ -47,9 +95,10 @@ New features:
   `#3293 <https://github.com/pybind/pybind11/pull/3293>`_
 
 * Improve the classes generated by ``bind_map``: `#3310 <https://github.com/pybind/pybind11/pull/3310>`_
-    * Change ``.items`` from an iterator to a dictionary view.
-    * Add ``.keys`` and ``.values`` (both dictionary views).
-    * Allow ``__contains__`` to take any object.
+
+  * Change ``.items`` from an iterator to a dictionary view.
+  * Add ``.keys`` and ``.values`` (both dictionary views).
+  * Allow ``__contains__`` to take any object.
 
 * ``pybind11::custom_type_setup`` was added, for customizing the
   ``PyHeapTypeObject`` corresponding to a class, which may be useful for
@@ -244,8 +293,8 @@ New features:
 
 Changes:
 
-* ``py::str`` changed to exclusively hold `PyUnicodeObject`. Previously
-  ``py::str`` could also hold `bytes`, which is probably surprising, was
+* ``py::str`` changed to exclusively hold ``PyUnicodeObject``. Previously
+  ``py::str`` could also hold ``bytes``, which is probably surprising, was
   never documented, and can mask bugs (e.g. accidental use of ``py::str``
   instead of ``py::bytes``).
   `#2409 <https://github.com/pybind/pybind11/pull/2409>`_
@@ -1398,7 +1447,7 @@ v2.2.0 (August 31, 2017)
 * Intel C++ compiler compatibility fixes.
   `#937 <https://github.com/pybind/pybind11/pull/937>`_.
 
-* Fixed implicit conversion of `py::enum_` to integer types on Python 2.7.
+* Fixed implicit conversion of ``py::enum_`` to integer types on Python 2.7.
   `#821 <https://github.com/pybind/pybind11/pull/821>`_.
 
 * Added ``py::hash`` to fetch the hash value of Python objects, and

docs/release.rst

@@ -27,6 +27,7 @@ To release a new version of pybind11:
       ``include/pybind11/detail/common.h``. PATCH should be a simple integer.
     - Update the version HEX just below, as well.
     - Update ``pybind11/_version.py`` (match above)
+    - Run ``nox -s tests_packaging`` to ensure this was done correctly.
     - Ensure that all the information in ``setup.cfg`` is up-to-date, like
       supported Python versions.
     - Add release date in ``docs/changelog.rst``.
@@ -49,13 +50,15 @@ To release a new version of pybind11:
 - Make a GitHub release (this shows up in the UI, sends new release
   notifications to users watching releases, and also uploads PyPI packages).
   (Note: if you do not use an existing tag, this creates a new lightweight tag
-  for you, so you could skip the above step).
-    - GUI method: click "Create a new release" on the far right, fill in the tag
-      name (if you didn't tag above, it will be made here), fill in a release
-      name like "Version X.Y.Z", and optionally copy-and-paste the changelog into
-      the description (processed as markdown by Pandoc). Check "pre-release" if
-      this is a beta/RC. You can get partway there with
-      ``cat docs/changelog.rst | pandoc -f rst -t gfm``.
+  for you, so you could skip the above step.)
+
+    - GUI method: Under `releases <https://github.com/pybind/pybind11/releases>`_
+      click "Draft a new release" on the far right, fill in the tag name
+      (if you didn't tag above, it will be made here), fill in a release name
+      like "Version X.Y.Z", and copy-and-paste the markdown-formatted (!) changelog
+      into the description (usually ``cat docs/changelog.rst | pandoc -f rst -t gfm``).
+      Check "pre-release" if this is a beta/RC.
+
     - CLI method: with ``gh`` installed, run ``gh release create vX.Y.Z -t "Version X.Y.Z"``
       If this is a pre-release, add ``-p``.
 
@@ -64,6 +67,7 @@ To release a new version of pybind11:
     - Update version macros in ``include/pybind11/detail/common.h`` (set PATCH to
       ``0.dev1`` and increment MINOR).
     - Update ``_version.py`` to match
+    - Run ``nox -s tests_packaging`` to ensure this was done correctly.
     - Add a spot for in-development updates in ``docs/changelog.rst``.
     - ``git add``, ``git commit``, ``git push``
 
@@ -71,7 +75,7 @@ If a version branch is updated, remember to set PATCH to ``1.dev1``.
 
 If you'd like to bump homebrew, run:
 
-.. code-block::
+.. code-block:: console
 
     brew bump-formula-pr --url https://github.com/pybind/pybind11/archive/vX.Y.Z.tar.gz
 

docs/upgrade.rst

@@ -8,7 +8,17 @@ to a new version. But it goes into more detail. This includes things like
 deprecated APIs and their replacements, build system changes, general code
 modernization and other useful information.
 
-.. _upgrade-guide-2.6:
+.. _upgrade-guide-2.9:
+
+v2.9
+====
+
+* Any usage of the recently added ``py::make_simple_namespace`` should be
+  converted to using ``py::module_::import("types").attr("SimpleNamespace")``
+  instead.
+
+
+.. _upgrade-guide-2.7:
 
 v2.7
 ====
@@ -34,6 +44,7 @@ to be common:
   careful review and custom fixes.
 
 
+.. _upgrade-guide-2.6:
 
 v2.6
 ====

include/pybind11/cast.h

@@ -1036,16 +1036,6 @@ template <return_value_policy policy = return_value_policy::automatic_reference,
     return result;
 }
 
-#if PY_VERSION_HEX >= 0x03030000
-template <typename... Args,
-          typename = detail::enable_if_t<args_are_all_keyword_or_ds<Args...>()>>
-object make_simple_namespace(Args&&... args_) {
-    PyObject *ns = _PyNamespace_New(dict(std::forward<Args>(args_)...).ptr());
-    if (!ns) throw error_already_set();
-    return reinterpret_steal<object>(ns);
-}
-#endif
-
 /// \ingroup annotations
 /// Annotation for arguments
 struct arg {

include/pybind11/detail/common.h

@@ -11,11 +11,11 @@
 
 #define PYBIND11_VERSION_MAJOR 2
 #define PYBIND11_VERSION_MINOR 8
-#define PYBIND11_VERSION_PATCH 0
+#define PYBIND11_VERSION_PATCH 1
 
 // Similar to Python's convention: https://docs.python.org/3/c-api/apiabiversion.html
 // Additional convention: 0xD = dev
-#define PYBIND11_VERSION_HEX 0x02080000
+#define PYBIND11_VERSION_HEX 0x02080100
 
 #define PYBIND11_NAMESPACE_BEGIN(name) namespace name {
 #define PYBIND11_NAMESPACE_END(name) }
@@ -831,6 +831,7 @@ PYBIND11_RUNTIME_EXCEPTION(value_error, PyExc_ValueError)
 PYBIND11_RUNTIME_EXCEPTION(type_error, PyExc_TypeError)
 PYBIND11_RUNTIME_EXCEPTION(buffer_error, PyExc_BufferError)
 PYBIND11_RUNTIME_EXCEPTION(import_error, PyExc_ImportError)
+PYBIND11_RUNTIME_EXCEPTION(attribute_error, PyExc_AttributeError)
 PYBIND11_RUNTIME_EXCEPTION(cast_error, PyExc_RuntimeError) /// Thrown when pybind11::cast or handle::call fail due to a type casting error
 PYBIND11_RUNTIME_EXCEPTION(reference_cast_error, PyExc_RuntimeError) /// Used internally
 

include/pybind11/detail/type_caster_base.h

@@ -468,12 +468,19 @@ PYBIND11_NOINLINE std::string error_string() {
         PyFrameObject *frame = trace->tb_frame;
         errorString += "\n\nAt:\n";
         while (frame) {
+#if PY_VERSION_HEX >= 0x03090000
+            PyCodeObject *f_code = PyFrame_GetCode(frame);
+#else
+            PyCodeObject *f_code = frame->f_code;
+            Py_INCREF(f_code);
+#endif
             int lineno = PyFrame_GetLineNumber(frame);
             errorString +=
-                "  " + handle(frame->f_code->co_filename).cast<std::string>() +
+                "  " + handle(f_code->co_filename).cast<std::string>() +
                 "(" + std::to_string(lineno) + "): " +
-                handle(frame->f_code->co_name).cast<std::string>() + "\n";
+                handle(f_code->co_name).cast<std::string>() + "\n";
             frame = frame->f_back;
+            Py_DECREF(f_code);
         }
     }
 #endif

include/pybind11/eigen.h

@@ -17,9 +17,23 @@
 
 #include "numpy.h"
 
+// The C4127 suppression was introduced for Eigen 3.4.0. In theory we could
+// make it version specific, or even remove it later, but considering that
+// 1. C4127 is generally far more distracting than useful for modern template code, and
+// 2. we definitely want to ignore any MSVC warnings originating from Eigen code,
+// it is probably best to keep this around indefinitely.
+#if defined(_MSC_VER)
+#  pragma warning(push)
+#  pragma warning(disable: 4127) // C4127: conditional expression is constant
+#endif
+
 #include <Eigen/Core>
 #include <Eigen/SparseCore>
 
+#if defined(_MSC_VER)
+#  pragma warning(pop)
+#endif
+
 // Eigen prior to 3.2.7 doesn't have proper move constructors--but worse, some classes get implicit
 // move constructors that break things.  We could detect this an explicitly copy, but an extra copy
 // of matrices seems highly undesirable.
@@ -559,7 +573,9 @@ struct type_caster<Type, enable_if_t<is_eigen_sparse<Type>::value>> {
         if (!values || !innerIndices || !outerIndices)
             return false;
 
-        value = Eigen::MappedSparseMatrix<Scalar, Type::Flags, StorageIndex>(
+        value = Eigen::MappedSparseMatrix<Scalar,
+                                          Type::Flags & (Eigen::RowMajor | Eigen::ColMajor),
+                                          StorageIndex>(
             shape[0].cast<Index>(), shape[1].cast<Index>(), nnz,
             outerIndices.mutable_data(), innerIndices.mutable_data(), values.mutable_data());
 

include/pybind11/eval.h

 /*
-    pybind11/exec.h: Support for evaluating Python expressions and statements
+    pybind11/eval.h: Support for evaluating Python expressions and statements
     from strings and files
 
     Copyright (c) 2016 Klemens Morgenstern <klemens.morgenstern@ed-chemnitz.de> and

include/pybind11/functional.h

@@ -69,7 +69,7 @@ public:
         // ensure GIL is held during functor destruction
         struct func_handle {
             function f;
-#if !(defined(_MSC_VER) && _MSC_VER == 1916 && defined(PYBIND11_CPP17) && PY_MAJOR_VERSION < 3)
+#if !(defined(_MSC_VER) && _MSC_VER == 1916 && defined(PYBIND11_CPP17))
             // This triggers a syntax error under very special conditions (very weird indeed).
             explicit
 #endif