Add setuptools.command.build (#3256)

changelog.d/3256.change.rst

@@ -0,0 +1 @@
+Added setuptools.command.build command to match distutils.command.build -- by :user:`isuruf`

setup.cfg

@@ -106,6 +106,7 @@ distutils.commands =
 	alias = setuptools.command.alias:alias
 	bdist_egg = setuptools.command.bdist_egg:bdist_egg
 	bdist_rpm = setuptools.command.bdist_rpm:bdist_rpm
+	build = setuptools.command.build:build
 	build_clib = setuptools.command.build_clib:build_clib
 	build_ext = setuptools.command.build_ext:build_ext
 	build_py = setuptools.command.build_py:build_py

setuptools/command/build.py

@@ -0,0 +1,24 @@
+from distutils.command.build import build as _build
+import warnings
+
+from setuptools import SetuptoolsDeprecationWarning
+
+
+_ORIGINAL_SUBCOMMANDS = {"build_py", "build_clib", "build_ext", "build_scripts"}
+
+
+class build(_build):
+    # copy to avoid sharing the object with parent class
+    sub_commands = _build.sub_commands[:]
+
+    def run(self):
+        subcommands = {cmd[0] for cmd in _build.sub_commands}
+        if subcommands - _ORIGINAL_SUBCOMMANDS:
+            msg = """
+            It seems that you are using `distutils.command.build.build` to add
+            new subcommands. Using `distutils` directly is considered deprecated,
+            please use `setuptools.command.build`.
+            """
+            warnings.warn(msg, SetuptoolsDeprecationWarning)
+            self.sub_commands = _build.sub_commands
+        super().run()

setuptools/tests/test_build.py

@@ -0,0 +1,63 @@
+from contextlib import contextmanager
+from setuptools import Command, SetuptoolsDeprecationWarning
+from setuptools.dist import Distribution
+from setuptools.command.build import build
+from distutils.command.build import build as distutils_build
+
+import pytest
+
+
+def test_distribution_gives_setuptools_build_obj(tmpdir_cwd):
+    """
+    Check that the setuptools Distribution uses the
+    setuptools specific build object.
+    """
+
+    dist = Distribution(dict(
+        script_name='setup.py',
+        script_args=['build'],
+        packages=[],
+        package_data={'': ['path/*']},
+    ))
+    assert isinstance(dist.get_command_obj("build"), build)
+
+
+@contextmanager
+def _restore_sub_commands():
+    orig = distutils_build.sub_commands[:]
+    try:
+        yield
+    finally:
+        distutils_build.sub_commands = orig
+
+
+class Subcommand(Command):
+    """Dummy command to be used in tests"""
+
+    def initialize_options(self):
+        pass
+
+    def finalize_options(self):
+        pass
+
+    def run(self):
+        raise NotImplementedError("just to check if the command runs")
+
+
+@_restore_sub_commands()
+def test_subcommand_in_distutils(tmpdir_cwd):
+    """
+    Ensure that sub commands registered in ``distutils`` run,
+    after instructing the users to migrate to ``setuptools``.
+    """
+    dist = Distribution(dict(
+        packages=[],
+        cmdclass={'subcommand': Subcommand},
+    ))
+    distutils_build.sub_commands.append(('subcommand', None))
+
+    warning_msg = "please use .setuptools.command.build."
+    with pytest.warns(SetuptoolsDeprecationWarning, match=warning_msg):
+        # For backward compatibility, the subcommand should run anyway:
+        with pytest.raises(NotImplementedError, match="the command runs"):
+            dist.run_command("build")