Merge branch 'feature/pep517-metadata' into 'master'

Add routine for loading metadata from a source package.

See merge request python-devs/importlib_metadata!113

Author: jaraco

importlib_metadata/__init__.py

@@ -242,6 +242,17 @@ def _discover_resolvers():
             )
         return filter(None, declared)
 
+    @classmethod
+    def _local(cls, root='.'):
+        from pep517 import build, meta
+        system = build.compat_system(root)
+        builder = functools.partial(
+            meta.build,
+            source_dir=root,
+            system=system,
+            )
+        return PathDistribution(zipp.Path(meta.build_as_zip(builder)))
+
     @property
     def metadata(self):
         """Return the parsed metadata for this Distribution.

importlib_metadata/docs/changelog.rst

@@ -5,6 +5,11 @@
 v1.6.1
 ======
 
+* Added ``Distribution._local()`` as a provisional
+  demonstration of how to load metadata for a local
+  package. Implicitly requires that
+  `pep517 <https://pypi.org/project/pep517>`_ is
+  installed. Ref #42.
 * Ensure inputs to FastPath are Unicode. Closes #121.
 * Tests now rely on ``importlib.resources.files`` (and
   backport) instead of the older ``path`` function.

importlib_metadata/tests/fixtures.py

@@ -166,6 +166,21 @@ def setUp(self):
         build_files(EggInfoFile.files, prefix=self.site_dir)
 
 
+class LocalPackage:
+    files = {
+        "setup.py": """
+            import setuptools
+            setuptools.setup(name="local-pkg", version="2.0.1")
+            """,
+        }
+
+    def setUp(self):
+        self.fixtures = contextlib.ExitStack()
+        self.addCleanup(self.fixtures.close)
+        self.fixtures.enter_context(tempdir_as_cwd())
+        build_files(self.files)
+
+
 def build_files(file_defs, prefix=pathlib.Path()):
     """Build a set of files/directories, as described by the
 

importlib_metadata/tests/test_api.py

@@ -174,3 +174,10 @@ def test_distribution_at_str(self):
         dist_info_path = self.site_dir / 'distinfo_pkg-1.0.0.dist-info'
         dist = Distribution.at(str(dist_info_path))
         assert dist.version == '1.0.0'
+
+
+class LocalProjectTests(fixtures.LocalPackage, unittest.TestCase):
+    def test_find_local(self):
+        dist = Distribution._local()
+        assert dist.metadata['Name'] == 'local-pkg'
+        assert dist.version == '2.0.1'

setup.cfg

@@ -55,6 +55,7 @@ universal=1
 testing =
     importlib_resources>=1.3; python_version < "3.9"
     packaging
+    pep517
 docs =
     sphinx
     rst.linker