Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

git merge smart_holder (pybind/pybind11#5174) #30128

Merged
merged 9 commits into from
Jun 19, 2024
2 changes: 1 addition & 1 deletion .github/workflows/ci.yml
Original file line number Diff line number Diff line change
Expand Up @@ -1112,7 +1112,7 @@ jobs:
uses: jwlawson/[email protected]

- name: Install ninja-build tool
uses: seanmiddleditch/gha-setup-ninja@v4
uses: seanmiddleditch/gha-setup-ninja@v5

- name: Run pip installs
run: |
Expand Down
2 changes: 1 addition & 1 deletion .github/workflows/ci_sh_def.yml
Original file line number Diff line number Diff line change
Expand Up @@ -1143,7 +1143,7 @@ jobs:
uses: jwlawson/[email protected]

- name: Install ninja-build tool
uses: seanmiddleditch/gha-setup-ninja@v4
uses: seanmiddleditch/gha-setup-ninja@v5

- name: Run pip installs
run: |
Expand Down
4 changes: 2 additions & 2 deletions .github/workflows/ci_sh_def.yml.patch
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
--- ci.yml 2024-06-10 13:25:02.926609611 -0700
+++ ci_sh_def.yml 2024-06-10 15:09:50.700252443 -0700
--- ci.yml 2024-06-19 10:06:18.454361731 -0700
+++ ci_sh_def.yml 2024-06-19 10:07:59.514269934 -0700
@@ -1,4 +1,16 @@
-name: CI
+# PLEASE KEEP THIS GROUP OF FILES IN SYNC AT ALL TIMES:
Expand Down
231 changes: 154 additions & 77 deletions docs/compiling.rst
Original file line number Diff line number Diff line change
Expand Up @@ -3,15 +3,123 @@
Build systems
#############

For an overview of Python packaging including compiled packaging with a pybind11
example, along with a cookiecutter that includes several pybind11 options, see
the `Scientific Python Development Guide`_.

.. _Scientific Python Development Guide: https://learn.scientific-python.org/development/guides/packaging-compiled/

.. scikit-build-core:

Modules with CMake
==================

A Python extension module can be created with just a few lines of code:

.. code-block:: cmake

cmake_minimum_required(VERSION 3.15...3.29)
project(example LANGUAGES CXX)

set(PYBIND11_FINDPYTHON ON)
find_package(pybind11 CONFIG REQUIRED)

pybind11_add_module(example example.cpp)
install(TARGET example DESTINATION .)

(You use the ``add_subdirectory`` instead, see the example in :ref:`cmake`.) In
this example, the code is located in a file named :file:`example.cpp`. Either
method will import the pybind11 project which provides the
``pybind11_add_module`` function. It will take care of all the details needed
to build a Python extension module on any platform.

To build with pip, build, cibuildwheel, uv, or other Python tools, you can
add a ``pyproject.toml`` file like this:

.. code-block:: toml

[build-system]
requires = ["scikit-build-core", "pybind11"]
build-backend = "scikit_build_core.build"

[project]
name = "example"
version = "0.1.0"

You don't need setuptools files like ``MANIFEST.in``, ``setup.py``, or
``setup.cfg``, as this is not setuptools. See `scikit-build-core`_ for details.
For projects you plan to upload to PyPI, be sure to fill out the ``[project]``
table with other important metadata as well (see `Writing pyproject.toml`_).

A working sample project can be found in the [scikit_build_example]_
repository. An older and harder-to-maintain method is in [cmake_example]_. More
details about our cmake support can be found below in :ref:`cmake`.

.. _scikit-build-core: https://scikit-build-core.readthedocs.io

.. [scikit_build_example] https://github.com/pybind/scikit_build_example

.. [cmake_example] https://github.com/pybind/cmake_example

.. _modules-meson-python:

Modules with meson-python
=========================

You can also build a package with `Meson`_ using `meson-python`_, if you prefer
that. Your ``meson.build`` file would look something like this:

.. _meson-example:

.. code-block:: meson

project(
'example',
'cpp',
version: '0.1.0',
default_options: [
'cpp_std=c++11',
],
)

py = import('python').find_installation(pure: false)
pybind11_dep = dependency('pybind11')

py.extension_module('example',
'example.cpp',
install: true,
dependencies : [pybind11_dep],
)


And you would need a ``pyproject.toml`` file like this:

.. code-block:: toml

[build-system]
requires = ["meson-python", "pybind11"]
build-backend = "mesonpy"

Meson-python *requires* your project to be in git (or mercurial) as it uses it
for the SDist creation. For projects you plan to upload to PyPI, be sure to fill out the
``[project]`` table as well (see `Writing pyproject.toml`_).


.. _Writing pyproject.toml: https://packaging.python.org/en/latest/guides/writing-pyproject-toml

.. _meson: https://mesonbuild.com

.. _meson-python: https://meson-python.readthedocs.io/en/latest

.. _build-setuptools:

Building with setuptools
========================
Modules with setuptools
=======================

For projects on PyPI, building with setuptools is the way to go. Sylvain Corlay
has kindly provided an example project which shows how to set up everything,
including automatic generation of documentation using Sphinx. Please refer to
the [python_example]_ repository.
For projects on PyPI, a historically popular option is setuptools. Sylvain
Corlay has kindly provided an example project which shows how to set up
everything, including automatic generation of documentation using Sphinx.
Please refer to the [python_example]_ repository.

.. [python_example] https://github.com/pybind/python_example

Expand All @@ -21,11 +129,11 @@ To use pybind11 inside your ``setup.py``, you have to have some system to
ensure that ``pybind11`` is installed when you build your package. There are
four possible ways to do this, and pybind11 supports all four: You can ask all
users to install pybind11 beforehand (bad), you can use
:ref:`setup_helpers-pep518` (good, but very new and requires Pip 10),
:ref:`setup_helpers-setup_requires` (discouraged by Python packagers now that
PEP 518 is available, but it still works everywhere), or you can
:ref:`setup_helpers-copy-manually` (always works but you have to manually sync
your copy to get updates).
:ref:`setup_helpers-pep518` (good), ``setup_requires=`` (discouraged), or you
can :ref:`setup_helpers-copy-manually` (works but you have to manually sync
your copy to get updates). Third party packagers like conda-forge generally
strongly prefer the ``pyproject.toml`` method, as it gives them control over
the ``pybind11`` version, and they may apply patches, etc.

An example of a ``setup.py`` using pybind11's helpers:

Expand Down Expand Up @@ -122,70 +230,41 @@ version number that includes the number of commits since your last tag and a
hash for a dirty directory. Another way to force a rebuild is purge your cache
or use Pip's ``--no-cache-dir`` option.

You also need a ``MANIFEST.in`` file to include all relevant files so that you
can make an SDist. If you use `pypa-build`_, that will build an SDist then a
wheel from that SDist by default, so you can look inside those files (wheels
are just zip files with a ``.whl`` extension) to make sure you aren't missing
files. `check-manifest`_ (setuptools specific) or `check-sdist`_ (general) are
CLI tools that can compare the SDist contents with your source control.

.. [Ccache] https://ccache.dev

.. [setuptools_scm] https://github.com/pypa/setuptools_scm

.. _setup_helpers-pep518:

PEP 518 requirements (Pip 10+ required)
---------------------------------------
Build requirements
------------------

If you use `PEP 518's <https://www.python.org/dev/peps/pep-0518/>`_
``pyproject.toml`` file, you can ensure that ``pybind11`` is available during
the compilation of your project. When this file exists, Pip will make a new
virtual environment, download just the packages listed here in ``requires=``,
and build a wheel (binary Python package). It will then throw away the
environment, and install your wheel.
With a ``pyproject.toml`` file, you can ensure that ``pybind11`` is available
during the compilation of your project. When this file exists, Pip will make a
new virtual environment, download just the packages listed here in
``requires=``, and build a wheel (binary Python package). It will then throw
away the environment, and install your wheel.

Your ``pyproject.toml`` file will likely look something like this:

.. code-block:: toml

[build-system]
requires = ["setuptools>=42", "pybind11>=2.6.1"]
requires = ["setuptools", "pybind11"]
build-backend = "setuptools.build_meta"

.. note::

The main drawback to this method is that a `PEP 517`_ compliant build tool,
such as Pip 10+, is required for this approach to work; older versions of
Pip completely ignore this file. If you distribute binaries (called wheels
in Python) using something like `cibuildwheel`_, remember that ``setup.py``
and ``pyproject.toml`` are not even contained in the wheel, so this high
Pip requirement is only for source builds, and will not affect users of
your binary wheels. If you are building SDists and wheels, then
`pypa-build`_ is the recommended official tool.

.. _PEP 517: https://www.python.org/dev/peps/pep-0517/
.. _cibuildwheel: https://cibuildwheel.readthedocs.io
.. _pypa-build: https://pypa-build.readthedocs.io/en/latest/

.. _setup_helpers-setup_requires:

Classic ``setup_requires``
--------------------------

If you want to support old versions of Pip with the classic
``setup_requires=["pybind11"]`` keyword argument to setup, which triggers a
two-phase ``setup.py`` run, then you will need to use something like this to
ensure the first pass works (which has not yet installed the ``setup_requires``
packages, since it can't install something it does not know about):

.. code-block:: python

try:
from pybind11.setup_helpers import Pybind11Extension
except ImportError:
from setuptools import Extension as Pybind11Extension


It doesn't matter that the Extension class is not the enhanced subclass for the
first pass run; and the second pass will have the ``setup_requires``
requirements.

This is obviously more of a hack than the PEP 518 method, but it supports
ancient versions of Pip.
.. _cibuildwheel: https://cibuildwheel.pypa.io
.. _pypa-build: https://build.pypa.io/en/latest/
.. _check-manifest: https://pypi.io/project/check-manifest
.. _check-sdist: https://pypi.io/project/check-sdist

.. _setup_helpers-copy-manually:

Expand Down Expand Up @@ -231,39 +310,30 @@ the C++ source file. Python is then able to find the module and load it.

.. [cppimport] https://github.com/tbenthompson/cppimport



.. _cmake:

Building with CMake
===================

For C++ codebases that have an existing CMake-based build system, a Python
extension module can be created with just a few lines of code:

.. code-block:: cmake

cmake_minimum_required(VERSION 3.5...3.29)
project(example LANGUAGES CXX)
extension module can be created with just a few lines of code, as seen above in
the module section. Pybind11 currently supports a lower minimum if you don't
use the modern FindPython, though be aware that CMake 3.27 removed the old
mechanism, so pybind11 will automatically switch if the old mechanism is not
available. Please opt into the new mechanism if at all possible. Our default
may change in future versions. This is the minimum required:

add_subdirectory(pybind11)
pybind11_add_module(example example.cpp)

This assumes that the pybind11 repository is located in a subdirectory named
:file:`pybind11` and that the code is located in a file named :file:`example.cpp`.
The CMake command ``add_subdirectory`` will import the pybind11 project which
provides the ``pybind11_add_module`` function. It will take care of all the
details needed to build a Python extension module on any platform.

A working sample project, including a way to invoke CMake from :file:`setup.py` for
PyPI integration, can be found in the [cmake_example]_ repository.

.. [cmake_example] https://github.com/pybind/cmake_example

.. versionchanged:: 2.6
CMake 3.4+ is required.

.. versionchanged:: 2.11
CMake 3.5+ is required.


Further information can be found at :doc:`cmake/index`.

pybind11_add_module
Expand Down Expand Up @@ -616,6 +686,13 @@ Building with Bazel
You can build with the Bazel build system using the `pybind11_bazel
<https://github.com/pybind/pybind11_bazel>`_ repository.

Building with Meson
===================

You can use Meson, which has support for ``pybind11`` as a dependency (internally
relying on our ``pkg-config`` support). See the :ref:`module example above <meson-example>`.


Generating binding code automatically
=====================================

Expand Down
6 changes: 3 additions & 3 deletions docs/requirements.txt
Original file line number Diff line number Diff line change
Expand Up @@ -269,7 +269,7 @@ sphinxcontrib-svg2pdfconverter==1.2.2 \
--hash=sha256:04ec767b55780a6b18d89cc1a8ada6d900c6efde9d1683abdb98a49b144465ca \
--hash=sha256:80a55ca61f70eae93efc65f3814f2f177c86ba55934a9f6c5022f1778b62146b
# via -r requirements.in
urllib3==2.2.1 \
--hash=sha256:450b20ec296a467077128bff42b73080516e71b56ff59a60a02bef2232c4fa9d \
--hash=sha256:d0570876c61ab9e520d776c38acbbb5b05a776d3f9ff98a5c8fd5162a444cf19
urllib3==2.2.2 \
--hash=sha256:a448b2f64d686155468037e1ace9f2d2199776e17f0a46610480d311f73e3472 \
--hash=sha256:dd505485549a7a552833da5e6063639d0d177c04f23bc3864e41e5dc5f612168
# via requests
Loading
Loading