Meson Python build backend

Warnings

• breaking Python 3.7 support was dropped in meson-python 0.18.0, and Python 3.8 support was dropped in 0.19.0. Projects using these older Python versions will need to upgrade to at least Python 3.9.
  Fix: Upgrade your project's Python interpreter to 3.9 or newer.
• breaking The minimum required Meson version was bumped to 0.64.0 in meson-python 0.18.0, and Meson 1.2.3 or later is required for Python 3.12+ in meson-python 0.15.0.
  Fix: Ensure that Meson version 0.64.0 or newer (or 1.2.3+ for Python 3.12+) is installed in your build environment.
• gotcha Meson's `install_data()` function installs non-package data files to a platform-specific location, making them difficult to reliably find at runtime after wheel installation.
  Fix: For data files needed at runtime, include them within your Python package alongside the code and access them using `importlib.resources` (or the `importlib-resources` backport for older Python versions).
• gotcha Passing native build options to Meson via `pip` or `build` can be complex due to the layers of abstraction introduced by the PEP 517 backend. Full control over Meson flags might be hindered.
  Fix: While some options can be passed via environment variables or specific build frontend flags, for fine-grained control or complex native configurations, consider an explicit `meson setup` step before invoking the Python build frontend, or consult `meson-python` documentation on passing build config settings.
• gotcha Changes in `os.path.isabs` semantics in Python 3.13 have been reported to break Meson's path detection on Windows, which could lead to build failures for projects using `meson-python`.
  Fix: Monitor `meson-python` and Meson project releases for compatibility fixes with Python 3.13. If encountering issues, consider using an earlier Python version until a fix is available.

Install

• pip install meson-python Install meson-python
• pip install build meson ninja Install build tools (recommended)

Imports

• mesonpy

  # Defined in pyproject.toml
  [build-system]
  build-backend = 'mesonpy'

  meson-python is a build backend and is not typically imported into Python code. Its functionality is invoked by build frontends (like pip or build) via the 'build-backend' entry in pyproject.toml.

Quickstart

This quickstart demonstrates how to set up a minimal Python project using `meson-python` as the build backend. It involves creating a `pyproject.toml` to declare `mesonpy` as the backend and a `meson.build` file to define the build logic. The example then shows how to build a wheel distribution and optionally install and test it.

mkdir my_project
cd my_project

# Create pyproject.toml
cat <<EOL > pyproject.toml
[build-system]
requires = ["meson-python", "meson", "ninja"]
build-backend = "mesonpy"

[project]
name = "my_example_package"
version = "0.1.0"
EOL

# Create meson.build
cat <<EOL > meson.build
project('my_example_package', 'python', version: '0.1.0')
python = import('python').find_installation(pure: false)
python.install_sources(
    'src/my_example_package/__init__.py',
    subdir: 'my_example_package'
)
EOL

# Create a simple Python source file
mkdir -p src/my_example_package
cat <<EOL > src/my_example_package/__init__.py
def greet():
    return "Hello from my_example_package!"
EOL

# Build the package (e.g., a wheel)
python -m build --wheel

# Install and test (optional)
pip install dist/*.whl
python -c "from my_example_package import greet; print(greet())"