Include type information by default (#4021)

docs/userguide/miscellaneous.rst

@@ -10,6 +10,19 @@ These include all :term:`pure Python modules <Pure Module>` in the
 headers) listed as part of extensions when creating a :term:`source
 distribution (or "sdist")`.
 
+.. note::
+   .. versionadded:: v68.3.0
+      ``setuptools`` will attempt to include type information files
+      by default in the distribution
+      (``.pyi`` and ``py.typed``, as specified in :pep:`561`).
+
+    *Please note however that this feature is* **EXPERIMENTAL** *and may change in
+    the future.*
+
+    If you have ``.pyi`` and ``py.typed`` files in your project, but do not
+    wish to distribute them, you can opt out by setting
+    :doc:`exclude-package-data </userguide/datafiles>` to remove them.
+
 However, when building more complex packages (e.g. packages that include
 non-Python files, or that need to use custom C headers), you might find that
 not all files present in your project folder are included in package

newsfragments/3136.feature.rst

@@ -0,0 +1,2 @@
+Include type information (``py.typed``, ``*.pyi``) by default (#3136) -- by :user:`Danie-1`,
+**EXPERIMENTAL**.

setuptools/command/build_py.py

@@ -16,6 +16,9 @@
 from ..warnings import SetuptoolsDeprecationWarning
 
 
+_IMPLICIT_DATA_FILES = ('*.pyi', 'py.typed')
+
+
 def make_writable(target):
     os.chmod(target, os.stat(target).st_mode | stat.S_IWRITE)
 
@@ -116,6 +119,7 @@ def find_data_files(self, package, src_dir):
             self.package_data,
             package,
             src_dir,
+            extra_patterns=_IMPLICIT_DATA_FILES,
         )
         globs_expanded = map(partial(glob, recursive=True), patterns)
         # flatten the expanded globs into an iterable of matches
@@ -285,14 +289,15 @@ def exclude_data_files(self, package, src_dir, files):
         return list(unique_everseen(keepers))
 
     @staticmethod
-    def _get_platform_patterns(spec, package, src_dir):
+    def _get_platform_patterns(spec, package, src_dir, extra_patterns=[]):
         """
         yield platform-specific path patterns (suitable for glob
         or fn_match) from a glob-based spec (such as
         self.package_data or self.exclude_package_data)
         matching package in src_dir.
         """
         raw_patterns = itertools.chain(
+            extra_patterns,
             spec.get('', []),
             spec.get(package, []),
         )

setuptools/tests/test_build_meta.py

@@ -372,8 +372,10 @@ def test_build_with_pyproject_config(self, tmpdir, setup_script):
             "src": {
                 "foo": {
                     "__init__.py": "__version__ = '0.1'",
+                    "__init__.pyi": "__version__: str",
                     "cli.py": "def main(): print('hello world')",
                     "data.txt": "def main(): print('hello world')",
+                    "py.typed": "",
                 }
             },
         }
@@ -406,8 +408,10 @@ def test_build_with_pyproject_config(self, tmpdir, setup_script):
             'foo-0.1/src',
             'foo-0.1/src/foo',
             'foo-0.1/src/foo/__init__.py',
+            'foo-0.1/src/foo/__init__.pyi',
             'foo-0.1/src/foo/cli.py',
             'foo-0.1/src/foo/data.txt',
+            'foo-0.1/src/foo/py.typed',
             'foo-0.1/src/foo.egg-info',
             'foo-0.1/src/foo.egg-info/PKG-INFO',
             'foo-0.1/src/foo.egg-info/SOURCES.txt',
@@ -419,8 +423,10 @@ def test_build_with_pyproject_config(self, tmpdir, setup_script):
         }
         assert wheel_contents == {
             "foo/__init__.py",
+            "foo/__init__.pyi",  # include type information by default
             "foo/cli.py",
             "foo/data.txt",  # include_package_data defaults to True
+            "foo/py.typed",  # include type information by default
             "foo-0.1.dist-info/LICENSE.txt",
             "foo-0.1.dist-info/METADATA",
             "foo-0.1.dist-info/WHEEL",

setuptools/tests/test_build_py.py

@@ -319,3 +319,142 @@ def test_get_outputs(tmpdir_cwd):
         f"{build_lib}/mypkg/sub2/nested/__init__.py": "other/__init__.py",
         f"{build_lib}/mypkg/sub2/nested/mod3.py": "other/mod3.py",
     }
+
+
+class TestTypeInfoFiles:
+    PYPROJECTS = {
+        "default_pyproject": DALS(
+            """
+            [project]
+            name = "foo"
+            version = "1"
+            """
+        ),
+        "dont_include_package_data": DALS(
+            """
+            [project]
+            name = "foo"
+            version = "1"
+
+            [tools.setuptools]
+            include-package-data = false
+            """
+        ),
+        "exclude_type_info": DALS(
+            """
+            [project]
+            name = "foo"
+            version = "1"
+
+            [tools.setuptools]
+            include-package-data = false
+
+            [tool.setuptools.exclude-package-data]
+            "*" = ["py.typed", "*.pyi"]
+            """
+        ),
+    }
+
+    EXAMPLES = {
+        "simple_namespace": {
+            "directory_structure": {
+                "foo": {
+                    "bar.pyi": "",
+                    "py.typed": "",
+                    "__init__.py": "",
+                }
+            },
+            "expected_type_files": {"foo/bar.pyi", "foo/py.typed"},
+        },
+        "nested_inside_namespace": {
+            "directory_structure": {
+                "foo": {
+                    "bar": {
+                        "py.typed": "",
+                        "mod.pyi": "",
+                    }
+                }
+            },
+            "expected_type_files": {"foo/bar/mod.pyi", "foo/bar/py.typed"},
+        },
+        "namespace_nested_inside_regular": {
+            "directory_structure": {
+                "foo": {
+                    "namespace": {
+                        "foo.pyi": "",
+                    },
+                    "__init__.pyi": "",
+                    "py.typed": "",
+                }
+            },
+            "expected_type_files": {
+                "foo/namespace/foo.pyi",
+                "foo/__init__.pyi",
+                "foo/py.typed",
+            },
+        },
+    }
+
+    @pytest.mark.parametrize(
+        "pyproject", ["default_pyproject", "dont_include_package_data"]
+    )
+    @pytest.mark.parametrize("example", EXAMPLES.keys())
+    def test_type_files_included_by_default(self, tmpdir_cwd, pyproject, example):
+        structure = {
+            **self.EXAMPLES[example]["directory_structure"],
+            "pyproject.toml": self.PYPROJECTS[pyproject],
+        }
+        expected_type_files = self.EXAMPLES[example]["expected_type_files"]
+        jaraco.path.build(structure)
+
+        build_py = get_finalized_build_py()
+        outputs = get_outputs(build_py)
+        assert expected_type_files <= outputs
+
+    @pytest.mark.parametrize("pyproject", ["exclude_type_info"])
+    @pytest.mark.parametrize("example", EXAMPLES.keys())
+    def test_type_files_can_be_excluded(self, tmpdir_cwd, pyproject, example):
+        structure = {
+            **self.EXAMPLES[example]["directory_structure"],
+            "pyproject.toml": self.PYPROJECTS[pyproject],
+        }
+        expected_type_files = self.EXAMPLES[example]["expected_type_files"]
+        jaraco.path.build(structure)
+
+        build_py = get_finalized_build_py()
+        outputs = get_outputs(build_py)
+        assert expected_type_files.isdisjoint(outputs)
+
+    def test_stub_only_package(self, tmpdir_cwd):
+        structure = {
+            "pyproject.toml": DALS(
+                """
+                [project]
+                name = "foo-stubs"
+                version = "1"
+                """
+            ),
+            "foo-stubs": {"__init__.pyi": "", "bar.pyi": ""},
+        }
+        expected_type_files = {"foo-stubs/__init__.pyi", "foo-stubs/bar.pyi"}
+        jaraco.path.build(structure)
+
+        build_py = get_finalized_build_py()
+        outputs = get_outputs(build_py)
+        assert expected_type_files <= outputs
+
+
+def get_finalized_build_py(script_name="%build_py-test%"):
+    dist = Distribution({"script_name": script_name})
+    dist.parse_config_files()
+    build_py = dist.get_command_obj("build_py")
+    build_py.finalize_options()
+    return build_py
+
+
+def get_outputs(build_py):
+    build_dir = Path(build_py.build_lib)
+    return {
+        os.path.relpath(x, build_dir).replace(os.sep, "/")
+        for x in build_py.get_outputs()
+    }