Add support for pyproject.toml-style configuration (PEP 621)

.gitignore

@@ -21,3 +21,4 @@ setuptools.egg-info
 .idea/
 .pytest_cache/
 .mypy_cache/
+/setuptools/tests/config/downloads

bootstrap.egg-info/entry_points.txt

@@ -2,6 +2,11 @@
 egg_info = setuptools.command.egg_info:egg_info
 build_py = setuptools.command.build_py:build_py
 sdist = setuptools.command.sdist:sdist
+dist_info = setuptools.command.dist_info:dist_info
+develop = setuptools.command.develop:develop
+install_scripts = setuptools.command.install_scripts:install_scripts
+bdist_egg = setuptools.command.bdist_egg:bdist_egg
+install_egg_info = setuptools.command.install_egg_info:install_egg_info
 
 [distutils.setup_keywords]
 include_package_data = setuptools.dist:assert_bool

changelog.d/2924.breaking.rst

@@ -0,0 +1,2 @@
+Removed public class ``SetupRequirementsError`` from the
+``setuptools.build_meta`` module.

changelog.d/2924.change.1.rst

@@ -0,0 +1,14 @@
+Added **experimental** support for ``pyproject.toml`` configuration
+(as introduced by :pep:`621`). Configuration parameters not covered by
+standards are handled in the ``[tool.setuptools]`` sub-table.
+
+Existing ``setup.cfg`` configuration is now automatically converted into the
+``pyproject.toml`` equivalent before taking effect (as proposed in
+:issue:`1688`).
+During the transition period, if this conversion results in non compatible
+settings, setuptools will fallback to the previous behaviour.
+
+Please note that the legacy backend does not support ``pyproject.toml``
+configuration.
+
+-- by :user:`abravalheri`.

changelog.d/2924.change.2.rst

@@ -0,0 +1,5 @@
+Added vendored dependencies for :pypi:`tomli`,
+:pypi:`validate-pyproject` and :pypi:`ini2toml`.
+
+These dependencies are used to read ``pyproject.toml``
+or automatically convert existing ``setup.cfg`` files.

changelog.d/2924.change.3.rst

@@ -0,0 +1,3 @@
+Changed means of interaction between ``setuptools.build_meta`` and
+``setuptools.setup``. Instead of simply executing the script, the backend now
+relies on ``distutils.core.run_setup`` to obtain a distribution object.

changelog.d/2924.deprecation.1.rst

@@ -0,0 +1,7 @@
+Deprecated ``setuptools.config.read_configuration``,
+``setuptools.config.parse_configuration`` and other functions or classes
+from ``setuptools.config``.
+
+This API is now replaced by ``setuptools.config.read`` and
+``setuptools.config.apply``, which *do not output* the same format of data
+(instead they are oriented toward the ``pyproject.toml`` format).

docs/conf.py

@@ -97,8 +97,12 @@
 # Add support for linking usernames
 github_url = 'https://github.com'
 github_sponsors_url = f'{github_url}/sponsors'
+repository = f'{github_url}/pypa/setuptools'
 extlinks = {
     'user': (f'{github_sponsors_url}/%s', '@'),  # noqa: WPS323
+    'issue': (f'{repository}/issues/%s', 'issue #%s'),  # noqa: WPS323
+    'pr': (f'{repository}/pull/%s', 'PR #%s'),  # noqa: WPS323
+    'pypi': ('https://pypi.org/project/%s', '%s'),  # noqa: WPS323
 }
 extensions += ['sphinx.ext.extlinks']
 

pavement.py

@@ -1,8 +1,13 @@
+import os
 import re
 import sys
+import shutil
 import subprocess
+import venv
+import string
+from tempfile import TemporaryDirectory
 
-from paver.easy import task, path as Path
+from paver.easy import info, task, path as Path
 
 
 def remove_all(paths):
@@ -55,7 +60,9 @@ def install(vendor):
     remove_all(vendor.glob('*.dist-info'))
     remove_all(vendor.glob('*.egg-info'))
     remove_all(vendor.glob('six.py'))
+    remove_ini2toml_extras(vendor)
     (vendor / '__init__.py').write_text('')
+    (vendor / 'bin').rmtree()
 
 
 def update_pkg_resources():
@@ -67,4 +74,59 @@ def update_pkg_resources():
 def update_setuptools():
     vendor = Path('setuptools/_vendor')
     install(vendor)
+    install_validate_pyproject(vendor)
     rewrite_packaging(vendor / 'packaging', 'setuptools.extern')
+
+
+def install_validate_pyproject(vendor):
+    """``validate-pyproject`` can be vendorized to remove all dependencies"""
+    req = next(
+        (x for x in (vendor / "vendored.txt").lines() if 'validate-pyproject' in x),
+        "validate-pyproject[all]"
+    )
+
+    pkg, _, _ = req.strip(string.whitespace + "#").partition("#")
+    pkg = pkg.strip()
+
+    opts = {}
+    if sys.version_info[:2] >= (3, 10):
+        opts["ignore_cleanup_errors"] = True
+
+    with TemporaryDirectory(**opts) as tmp:
+        venv.create(tmp, with_pip=True)
+        path = os.pathsep.join(Path(tmp).glob("*"))
+        venv_python = shutil.which("python", path=path)
+        info(f"Temporarily installing {pkg!r}...")
+        subprocess.check_call([venv_python, "-m", "pip", "install", pkg])
+        cmd = [
+            venv_python,
+            "-m",
+            "validate_pyproject.vendoring",
+            "--output-dir",
+            str(vendor / "_validate_pyproject"),
+            "--enable-plugins",
+            "setuptools",
+            "distutils",
+            "--very-verbose"
+        ]
+        subprocess.check_output(cmd)
+        info(f"{pkg!r} vendorized")
+
+
+def remove_ini2toml_extras(vendor):
+    """Remove unnecessary files from `ini2toml`"""
+    unecessary = [
+        "ini2toml/__main__.py",
+        "ini2toml/api.py",
+        "ini2toml/cli.py",
+        "ini2toml/drivers/configupdater.py",
+        "ini2toml/drivers/full_toml.py",
+        "ini2toml/drivers/lite_toml.py",
+        "ini2toml/plugins/coverage.py",
+        "ini2toml/plugins/isort.py",
+        "ini2toml/plugins/mypy.py",
+        "ini2toml/plugins/profile_independent_tasks.py",
+        "ini2toml/plugins/pytest.py",
+        "ini2toml/translator.py",
+    ]
+    remove_all(vendor / file for file in unecessary)