configure isolated builds, with declarative setuptools

pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = [ "setuptools >= 35.0.2", "wheel >= 0.29.0"]
+build-backend = "setuptools.build_meta"

setup.cfg

@@ -1,5 +1,6 @@
 [metadata]
 name = incremental
+version = attr: incremental._setuptools_version
 maintainer = Amber Brown
 maintainer_email = hawkowl@twistedmatrix.com
 url = https://github.com/twisted/incremental

setup.py

@@ -1,18 +0,0 @@
-#!/usr/bin/env python
-
-from __future__ import absolute_import, division, print_function
-
-import os
-import sys
-
-from setuptools import setup
-
-base_dir = os.path.dirname(__file__)
-src_dir = os.path.join(base_dir, "src")
-
-# We need to import outselves
-sys.path.insert(0, src_dir)
-
-import incremental
-
-setup(version=incremental.__version__.base())

src/incremental/__init__.py

@@ -391,4 +391,8 @@ def _get_version(dist, keyword, value):
 from ._version import __version__  # noqa
 
 
+def _setuptools_version():
+    return __version__.public()
+
+
 __all__ = ["__version__", "Version", "getVersionString"]

tox.ini

@@ -1,4 +1,9 @@
 [tox]
+minversion = 3.23.0
+requires =
+    virtualenv >= 20.4.3
+    tox-wheel >= 0.6.0
+isolated_build = true
 envlist =
     flake8,
     tests,
@@ -7,6 +12,8 @@ envlist =
 
 
 [testenv]
+wheel = true
+wheel_build_env = build
 deps =
     tests: coverage
     apidocs: pydoctor
@@ -41,3 +48,7 @@ commands =
 setenv =
 ; Clear the --check flag
     BLACK_LINT_ARGS=
+
+[testenv:build]
+# empty environment to build universal wheel once per tox invocation
+# https://github.com/ionelmc/tox-wheel#build-configuration