Remove legacy setup.py stuff (#124)

* Remove legacy setup.py stuff

* flake8

setup.py

@@ -2,10 +2,8 @@
 import io
 import platform
 import sys
-from distutils.command.build import build
 
 from setuptools import setup
-from setuptools.command.install import install
 from setuptools.command.test import test
 
 
@@ -45,158 +43,6 @@ def run_tests(self):
         sys.exit(errno)
 
 
-def keywords_with_side_effects(argv):
-    """
-    Get a dictionary with setup keywords that (can) have side effects.
-
-    :param argv: A list of strings with command line arguments.
-    :returns: A dictionary with keyword arguments for the ``setup()`` function.
-
-    This setup.py script uses the setuptools 'setup_requires' feature because
-    this is required by the cffi package to compile extension modules. The
-    purpose of ``keywords_with_side_effects()`` is to avoid triggering the cffi
-    build process as a result of setup.py invocations that don't need the cffi
-    module to be built (setup.py serves the dual purpose of exposing package
-    metadata).
-
-    All of the options listed by ``python setup.py --help`` that print
-    information should be recognized here. The commands ``clean``,
-    ``egg_info``, ``register``, ``sdist`` and ``upload`` are also recognized.
-    Any combination of these options and commands is also supported.
-
-    This function was originally based on the `setup.py script`_ of SciPy (see
-    also the discussion in `pip issue #25`_).
-
-    .. _pip issue #25: https://github.com/pypa/pip/issues/25
-    .. _setup.py script: https://github.com/scipy/scipy/blob/master/setup.py
-    """
-    no_setup_requires_arguments = (
-        "-h",
-        "--help",
-        "-n",
-        "--dry-run",
-        "-q",
-        "--quiet",
-        "-v",
-        "--verbose",
-        "-V",
-        "--version",
-        "--author",
-        "--author-email",
-        "--classifiers",
-        "--contact",
-        "--contact-email",
-        "--description",
-        "--egg-base",
-        "--fullname",
-        "--help-commands",
-        "--keywords",
-        "--licence",
-        "--license",
-        "--long-description",
-        "--maintainer",
-        "--maintainer-email",
-        "--name",
-        "--no-user-cfg",
-        "--obsoletes",
-        "--platforms",
-        "--provides",
-        "--requires",
-        "--url",
-        "clean",
-        "egg_info",
-        "register",
-        "sdist",
-        "upload",
-    )
-
-    def is_short_option(argument):
-        """Check whether a command line argument is a short option."""
-        return len(argument) >= 2 and argument[0] == "-" and argument[1] != "-"
-
-    def expand_short_options(argument):
-        """Expand combined short options into canonical short options."""
-        return ("-" + char for char in argument[1:])
-
-    def argument_without_setup_requirements(argv, i):
-        """Check whether a command line argument needs setup requirements."""
-        if argv[i] in no_setup_requires_arguments:
-            # Simple case: An argument which is either an option or a command
-            # which doesn't need setup requirements.
-            return True
-        elif is_short_option(argv[i]) and all(
-            option in no_setup_requires_arguments
-            for option in expand_short_options(argv[i])
-        ):
-            # Not so simple case: Combined short options none of which need
-            # setup requirements.
-            return True
-        elif argv[i - 1 : i] == ["--egg-base"]:
-            # Tricky case: --egg-info takes an argument which should not make
-            # us use setup_requires (defeating the purpose of this code).
-            return True
-        else:
-            return False
-
-    if all(
-        argument_without_setup_requirements(argv, i)
-        for i in range(1, len(argv))
-    ):
-        return {
-            "cmdclass": {
-                "build": DummyCFFIBuild,
-                "install": DummyCFFIInstall,
-                "test": DummyPyTest,
-            }
-        }
-    else:
-        return {
-            "setup_requires": [CFFI_DEPENDENCY],
-            "cmdclass": {"test": PyTest},
-            "cffi_modules": CFFI_MODULES,
-        }
-
-
-setup_requires_error = (
-    "Requested setup command that needs 'setup_requires' "
-    "while command line arguments implied a side effect "
-    "free command or option."
-)
-
-
-class DummyCFFIBuild(build):
-    """
-    This class makes it very obvious when ``keywords_with_side_effects()`` has
-    incorrectly interpreted the command line arguments to ``setup.py build`` as
-    one of the 'side effect free' commands or options.
-    """
-
-    def run(self):
-        raise RuntimeError(setup_requires_error)
-
-
-class DummyCFFIInstall(install):
-    """
-    This class makes it very obvious when ``keywords_with_side_effects()`` has
-    incorrectly interpreted the command line arguments to ``setup.py install``
-    as one of the 'side effect free' commands or options.
-    """
-
-    def run(self):
-        raise RuntimeError(setup_requires_error)
-
-
-class DummyPyTest(test):
-    """
-    This class makes it very obvious when ``keywords_with_side_effects()`` has
-    incorrectly interpreted the command line arguments to ``setup.py test`` as
-    one of the 'side effect free' commands or options.
-    """
-
-    def run_tests(self):
-        raise RuntimeError(setup_requires_error)
-
-
 setup(
     name=__about__["__title__"],
     version=__about__["__version__"],
@@ -207,6 +53,7 @@ def run_tests(self):
     author=__about__["__author__"],
     author_email=__about__["__email__"],
     python_requires=">=3.6",
+    setup_requires=[CFFI_DEPENDENCY],
     install_requires=[CFFI_DEPENDENCY, SIX_DEPENDENCY],
     extras_require={"tests": ["pytest>=3.2.1,!=3.3.0"], "typecheck": ["mypy"]},
     tests_require=["pytest>=3.2.1,!=3.3.0"],
@@ -225,5 +72,6 @@ def run_tests(self):
         "Programming Language :: Python :: 3.8",
     ],
     ext_package="bcrypt",
-    **keywords_with_side_effects(sys.argv)
+    cffi_modules=CFFI_MODULES,
+    cmdclass={"test": PyTest},
 )