Parse raw metadata (#671)

Co-authored-by: Donald Stufft <donald@stufft.io>
Co-authored-by: Paul Moore <p.f.moore@gmail.com>
Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>

.github/workflows/test.yml

@@ -23,7 +23,7 @@ jobs:
       matrix:
         os: [Ubuntu, Windows, macOS]
         python_version:
-          ["3.7", "3.8", "3.9", "3.10", "3.11", "pypy3.7", "pypy3.8", "pypy3.9"]
+          ["3.7", "3.8", "3.9", "3.10", "3.11", "pypy3.8", "pypy3.9"]
 
     steps:
       - uses: actions/checkout@v3

docs/index.rst

@@ -25,6 +25,7 @@ You can install packaging with ``pip``:
     specifiers
     markers
     requirements
+    metadata
     tags
     utils
 

docs/metadata.rst

@@ -0,0 +1,42 @@
+Metadata
+========
+
+.. currentmodule:: packaging.markers
+
+
+Both `source distributions`_ and `binary distributions`
+(_sdists_ and _wheels_, respectively) contain files recording the
+`core metadata`_ for the distribution. This information is used for
+everything from recording the name of the distribution to the
+installation dependencies.
+
+
+Usage
+-----
+
+.. doctest::
+
+    >>> from packaging.metadata import parse_email
+    >>> metadata = "Metadata-Version: 2.3\nName: packaging\nVersion: 24.0"
+    >>> raw, unparsed = parse_email(metadata)
+    >>> raw["metadata_version"]
+    '2.3'
+    >>> raw["name"]
+    'packaging'
+    >>> raw["version"]
+    '24.0'
+
+
+Reference
+---------
+
+Low Level Interface
+'''''''''''''''''''
+
+.. automodule:: packaging.metadata
+    :members:
+
+
+.. _source distributions: https://packaging.python.org/en/latest/specifications/source-distribution-format/
+.. _binary distributions: https://packaging.python.org/en/latest/specifications/binary-distribution-format/
+.. _core metadata: https://packaging.python.org/en/latest/specifications/core-metadata/

noxfile.py

@@ -21,9 +21,7 @@
 nox.options.reuse_existing_virtualenvs = True
 
 
-@nox.session(
-    python=["3.7", "3.8", "3.9", "3.10", "3.11", "pypy3.7", "pypy3.8", "pypy3.9"]
-)
+@nox.session(python=["3.7", "3.8", "3.9", "3.10", "3.11", "pypy3.8", "pypy3.9"])
 def tests(session):
     def coverage(*args):
         session.run("python", "-m", "coverage", *args)

src/packaging/_manylinux.py

@@ -14,6 +14,8 @@
 EF_ARM_ABI_FLOAT_HARD = 0x00000400
 
 
+# `os.PathLike` not a generic type until Python 3.9, so sticking with `str`
+# as the type for `path` until then.
 @contextlib.contextmanager
 def _parse_elf(path: str) -> Generator[Optional[ELFFile], None, None]:
     try: