Make gridtools-cpp installable from a git ref via scikit-build-core

.gitignore

@@ -47,6 +47,7 @@ __pycache__
 !LICENSE
 !mainpage.dox
 !modules
+!pyproject.toml
 !README.md
 !Vagrant_bootstrap.sh
 !Vagrantfile

.python_package/.gitignore

@@ -1,7 +1,4 @@
 .nox/
-LICENSE
 dist/
-setup.cfg
 *.egg-info/
-src/gridtools_cpp/data
 build/

.python_package/DEVELOPMENT.md

@@ -1,60 +1,50 @@
 # Development
 
-In order to be able to work on this package, it is necessary to run a preparation step.
-This will generate the `setup.cfg` file from `setup.cfg.in` and install the gridtools header distribution into the package data.
-It will read the version number from the top-level `version.txt` and copy the `LICENSE` file to where packaging tools can find it.
+The `gridtools-cpp` distribution is built from the repository root with
+[scikit-build-core](https://scikit-build-core.readthedocs.io/) (see the top-level
+`pyproject.toml`). The build runs the root `CMakeLists.txt` to install the headers and
+CMake config into the package data, and reads the version from `version.txt` — there is
+no separate preparation step.
 
-All of this requires `nox`, the preparation step runs in an isolated environment and installs additional requirements `cmake` and `ninja` at runtime.
+## Installing
+
+As always it is recommended to carry out the following steps in a virtual environment.
+From the repository root:
 
 ```bash
-pip install nox
-nox -s prepare
+pip install .
 ```
 
-To delete all generated files run
+Directly from a git ref (no subdirectory needed):
 
 ```bash
-nox -s clean clean_cache
+pip install "git+https://github.com/GridTools/gridtools.git@<ref>"
 ```
 
-where `clean_cache` deletes chached files from Nox sessions like CMake builds and testing wheels (found in `.nox/.cache`), and `clean` deletes visible artifacts like `dist/`, `build/`, `.egg-info/`.
-`setup.cfg` will not be deleted for convenience, to make sure tools keep functioning as expected.
-
-## Installing
-
-As always it is recommended to carry out the following steps in a virtual environment:
+## Building for distribution
 
 ```bash
-nox -s build -- --wheel .
-pip install dist/gridtools_cpp-2.2.0-py3-none-any.whl
+python -m build --wheel
 ```
 
+The header-only wheel is platform independent (`gridtools_cpp-<version>-py3-none-any.whl`).
+
 ## Testing
 
-Using nox, the tests will be carried out in isolated python environments for you:
+Using nox (from this directory), the tests run in isolated environments:
 
 ```bash
 nox -s test_src
 ```
 
-To test the wheel distribution specifically:
+To build and test the wheel distribution specifically:
 
 ```bash
 nox -s build_wheel test_wheel_with_python-3.10  # replace 3.10 with the Python version you are running
 ```
 
-## Advanced testing (all supported versions)
-
-The following requires you to have Python interpreters for Python 3.8, 3.9, 3.10 and 3.11 in your system path.
+To run against all supported versions (requires Python 3.8, 3.9, 3.10 and 3.11 in your path):
 
 ```bash
 nox
 ```
-
-## Building for distribution
-
-Uses (`build`)[https://pypa-build.readthedocs.io/en/latest/], follow the link for available options.
-
-```bash
-nox -s build -- <build options>
-```

.python_package/noxfile.py

@@ -6,80 +6,30 @@
 # Please, refer to the LICENSE file in the root directory.
 # SPDX-License-Identifier: BSD-3-Clause
 
-import configparser
-import pathlib
 import shutil
 
 import nox
 
 
-_RELATIVE_DATA_DIR = pathlib.Path("src/gridtools_cpp/data")
+_ROOT = ".."
 
 
 nox.options.sessions = ["test_src", "test_wheel"]
 
 
 @nox.session
-def prepare(session: nox.Session):
-    session.install("cmake>=3.18.1")
-    session.install("ninja")
-    build_path = session.cache_dir.joinpath("build").absolute()
-    build_path.mkdir(exist_ok=True)
-    install_path = pathlib.Path(".").absolute() / _RELATIVE_DATA_DIR
-    source_path = pathlib.Path("..").absolute()
-    with session.chdir(build_path):
-        session.run(
-            "cmake",
-            "-DBUILD_TESTING=OFF",
-            "-DGT_INSTALL_EXAMPLES:BOOL=OFF",
-            f"-DCMAKE_INSTALL_PREFIX={install_path}",
-            "-GNinja",
-            str(source_path),
-        )
-        session.run("cmake", "--install", ".")
-        session.log("installed gridttols sources")
-    version_path = source_path / "version.txt"
-    config = configparser.ConfigParser()
-    config.read("setup.cfg.in")
-    config["metadata"]["version"] = version_path.read_text().strip()
-    with open("setup.cfg", mode="w") as setup_fp:
-        config.write(setup_fp)
-    session.log("updated version metadata")
-    shutil.copy(source_path / "LICENSE", ".")
-    session.log("copied license file")
-
-
-def get_wheel(session: nox.Session) -> pathlib.Path:
-    return list(session.cache_dir.joinpath("dist").glob("gridtools_cpp-*.whl"))[0]
+def test_src(session: nox.Session):
+    session.install(_ROOT)
+    session.install("pytest")
+    session.run("pytest", "tests", *session.posargs)
 
 
 @nox.session
 def build_wheel(session: nox.Session):
-    prepare(session)
     dist_path = session.cache_dir.joinpath("dist").absolute()
-    nox_workdir = pathlib.Path(".").absolute()
-    session.install("build[virtualenv]", "wheel")
-    with session.chdir(session.cache_dir):
-        session.run(
-            "python",
-            "-m",
-            "build",
-            "--no-isolation",
-            "--wheel",
-            "-o",
-            str(dist_path),
-            str(nox_workdir),
-        )
+    session.install("build")
+    session.run("python", "-m", "build", "--wheel", "-o", str(dist_path), _ROOT)
     session.log(f"built wheel in {dist_path}")
-    session.log("\n".join(str(path) for path in dist_path.iterdir()))
-
-
-@nox.session
-def test_src(session: nox.Session):
-    prepare(session)
-    session.install(".")
-    session.install("pytest")
-    session.run("pytest", "tests", *session.posargs)
 
 
 @nox.session
@@ -93,34 +43,12 @@ def test_wheel(session: nox.Session):
 
 @nox.session(python=["3.8", "3.9", "3.10", "3.11"])
 def test_wheel_with_python(session: nox.Session):
-    wheel_path = get_wheel(session)
+    wheel_path = next(session.cache_dir.joinpath("dist").glob("gridtools_cpp-*.whl"))
     session.install("pytest")
     session.install(str(wheel_path))
     session.run("pytest", "tests", *session.posargs)
 
 
-@nox.session
-def clean_cache(session: nox.Session):
-    for subtree in session.cache_dir.iterdir():
-        shutil.rmtree(subtree, True)
-
-
-@nox.session
-def build(session: nox.Session):
-    prepare(session)
-    session.install("build[virtualenv]")
-    session.run("python", "-m", "build", "--no-isolation", *session.posargs)
-
-
 @nox.session
 def clean(session: nox.Session):
-    data_dir = _RELATIVE_DATA_DIR
-    session.log(f"rm -r {data_dir}")
-    shutil.rmtree(data_dir, True)
-    session.log("rm -r src/*.egg-info")
-    for egg_tree in pathlib.Path("src").glob("*.egg-info"):
-        shutil.rmtree(egg_tree, True)
-    session.log("rm -r dist")
-    shutil.rmtree("dist", True)
-    session.log("rm -r build")
-    shutil.rmtree("build", True)
+    shutil.rmtree(session.cache_dir.joinpath("dist"), True)

pyproject.toml

@@ -0,0 +1,42 @@
+[build-system]
+requires = ["scikit-build-core>=0.11"]
+build-backend = "scikit_build_core.build"
+
+[project]
+name = "gridtools-cpp"
+dynamic = ["version"]
+description = "Python package for GridTools headers and CMake files"
+readme = ".python_package/README.md"
+license = "BSD-3-Clause"
+license-files = ["LICENSE"]
+authors = [{ name = "ETH Zurich", email = "gridtools@cscs.ch" }]
+requires-python = ">=3.8"
+classifiers = [
+  "Development Status :: 5 - Production/Stable",
+  "Intended Audience :: Science/Research",
+  "Operating System :: OS Independent",
+  "Programming Language :: Python :: 3 :: Only",
+  "Topic :: Scientific/Engineering :: Atmospheric Science",
+  "Topic :: Scientific/Engineering :: Mathematics",
+  "Topic :: Scientific/Engineering :: Physics",
+]
+
+[project.urls]
+Homepage = "https://gridtools.github.io"
+"Source Code" = "https://github.com/GridTools/gridtools"
+
+[tool.scikit-build]
+cmake.version = ">=3.21"
+wheel.py-api = "py3"
+wheel.platlib = false
+wheel.packages = ["src/gridtools_cpp"]
+wheel.install-dir = "gridtools_cpp/data"
+
+[tool.scikit-build.cmake.define]
+BUILD_TESTING = "OFF"
+GT_INSTALL_EXAMPLES = "OFF"
+
+[tool.scikit-build.metadata.version]
+provider = "scikit_build_core.metadata.regex"
+input = "version.txt"
+regex = "(?P<value>.+)"