build: Migrate from setup.py to pyproject.toml

Using `setup.py` is deprecated and the new recommanded way is to declare
a `pyproject.toml` file (see PEP 517 [^1]).

This commit proposes to use setuptools to achieve that, because
setuptools is already used by yamllint, is standard and referenced by
the official Python packaging documentation [^2], and seems to be the
most lightweight solution. An alternative could have been to use Poetry,
see the dedicated pull request and discussion [^3].

For some period, the `setup.py` file will be kept (although almost
empty), to allow old tools versions to keep working.

Closes #509.

[^1]: https://peps.python.org/pep-0517/
[^2]: https://packaging.python.org/en/latest/tutorials/installing-packages/
[^3]: #557

.flake8

@@ -0,0 +1,4 @@
+[flake8]
+import-order-style = pep8
+application-import-names = yamllint
+ignore = W503,W504

.github/workflows/ci.yaml

@@ -21,9 +21,8 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v4
       - run:
-          python -m pip install flake8 flake8-import-order sphinx
-            rstcheck[sphinx] doc8
-      - run: python -m pip install .
+          pip install flake8 flake8-import-order sphinx rstcheck[sphinx] doc8
+      - run: pip install .
       - run: flake8 .
       - run: doc8 $(git ls-files '*.rst')
       - run: rstcheck --ignore-directives automodule $(git ls-files '*.rst')
@@ -53,8 +52,10 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: Append GitHub Actions system path
         run: echo "$HOME/.local/bin" >> $GITHUB_PATH
-      - run: pip install coveralls
+      - run: pip install coverage
       - run: pip install .
-      - run: coverage run --source=yamllint -m unittest discover
+      # https://github.com/AndreMiras/coveralls-python-action/issues/18
+      - run: echo -e "[run]\nrelative_files = True" > .coveragerc
+      - run: coverage run -m unittest discover
       - name: Coveralls
         uses: AndreMiras/coveralls-python-action@develop

docs/quickstart.rst

@@ -45,7 +45,7 @@ If you prefer installing from source, you can run, from the source directory:
 
 .. code:: bash
 
- python setup.py sdist
+ python -m build
  pip install --user dist/yamllint-*.tar.gz
 
 Running yamllint

pyproject.toml

@@ -0,0 +1,54 @@
+[project]
+name = "yamllint"
+description = "A linter for YAML files."
+readme = {file = "README.rst", content-type = "text/x-rst"}
+requires-python = ">=3.7"
+license = {text = "GPL-3.0-only"}
+authors = [{name = "Adrien Vergé"}]
+keywords = ["yaml", "lint", "linter", "syntax", "checker"]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Environment :: Console",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
+    "Programming Language :: Python",
+    "Topic :: Software Development",
+    "Topic :: Software Development :: Debuggers",
+    "Topic :: Software Development :: Quality Assurance",
+    "Topic :: Software Development :: Testing",
+]
+dependencies = [
+    "pathspec >= 0.5.3",
+    "pyyaml",
+]
+dynamic = ["version"]
+
+[project.optional-dependencies]
+dev = [
+    "doc8",
+    "flake8",
+    "flake8-import-order",
+    "rstcheck[sphinx]",
+    "sphinx",
+]
+
+[project.scripts]
+yamllint = "yamllint.cli:run"
+
+[project.urls]
+homepage = "https://github.com/adrienverge/yamllint"
+repository = "https://github.com/adrienverge/yamllint"
+documentation = "https://yamllint.readthedocs.io"
+
+[build-system]
+build-backend = "setuptools.build_meta"
+requires = ["setuptools >= 61"]
+
+[tool.setuptools]
+packages = ["yamllint", "yamllint.conf", "yamllint.rules"]
+
+[tool.setuptools.package-data]
+yamllint = ["conf/*.yaml"]
+
+[tool.setuptools.dynamic]
+version = {attr = "yamllint.__version__"}

setup.py

@@ -15,15 +15,6 @@
 
 from setuptools import setup
 
-from yamllint import (__author__, __license__,
-                      APP_NAME, APP_VERSION, APP_DESCRIPTION)
-
-
-setup(
-    name=APP_NAME,
-    version=APP_VERSION,
-    author=__author__,
-    description=APP_DESCRIPTION.split('\n')[0],
-    long_description=APP_DESCRIPTION,
-    license=__license__,
-)
+# This is only kept for backward-compatibility with older versions that don't
+# support new packaging standards (e.g. PEP 517 or PEP 660):
+setup()