migrate to parser based on hatchling's

- back away from vendoring
- adapt hatchling's license expression parser to accept well-formed LicenseRef-
- back to python storage of license data

.pre-commit-config.yaml

@@ -5,15 +5,13 @@ repos:
       - id: check-toml
       - id: check-yaml
       - id: end-of-file-fixer
-        exclude: '^src/packaging/_vendor'
       - id: trailing-whitespace
-        exclude: '^src/packaging/_vendor'
 
   - repo: https://github.com/pre-commit/mirrors-mypy
     rev: v0.991
     hooks:
       - id: mypy
-        exclude: '^(docs|tasks|tests)|setup\.py|^src/packaging/_vendor'
+        exclude: '^(docs|tasks|tests)|setup\.py'
         args: []
         additional_dependencies: [pyparsing, nox]
 

noxfile.py

@@ -1,6 +1,5 @@
 # mypy: disallow-untyped-defs=False, disallow-untyped-calls=False
 
-import argparse
 import contextlib
 import datetime
 import difflib
@@ -182,32 +181,10 @@ def release(session):
     webbrowser.open("https://github.com/pypa/packaging/releases")
 
 
-# NOTE: This session will COMMIT upgrades to vendored libraries.
-# You should therefore not run it directly against `main`. If you
-# do (assuming you started with a clean main), you can run:
-#
-# git checkout -b vendoring-updates
-# git checkout main
-# git reset --hard origin/main
 @nox.session
-def vendoring(session: nox.Session) -> None:
-    # Ensure that the session Python is running 3.10+
-    # so that truststore can be installed correctly.
-    session.run(
-        "python", "-c", "import sys; sys.exit(1 if sys.version_info < (3, 10) else 0)"
-    )
-
-    parser = argparse.ArgumentParser(prog="nox -s vendoring")
-    parser.add_argument("--upgrade-all", action="store_true")
-    parser.add_argument("--upgrade", action="append", default=[])
-    parser.add_argument("--skip", action="append", default=[])
-    args = parser.parse_args(session.posargs)
-
-    session.install("vendoring~=1.2.0")
-
-    if not (args.upgrade or args.upgrade_all):
-        session.run("vendoring", "sync", "-v")
-        return
+def update_licenses(session: nox.Session) -> None:
+    session.install("httpx")
+    session.run("python", "tasks/licenses.py")
 
 
 # -----------------------------------------------------------------------------

pyproject.toml

@@ -37,19 +37,11 @@ Source = "https://github.com/pypa/packaging"
 
 [tool.flit.sdist]
 include = ["LICENSE*", "tests/", "docs/", "CHANGELOG.rst"]
-exclude = ["docs/_build", "tests/manylinux/build-hello-world.sh", "tests/musllinux/build.sh", "tests/hello-world.c", "tests/__pycache__", "build/__pycache__", "src/packaging/_vendor/license_expression/data/*"]
-
-[tool.pytest.ini_options]
-addopts = [
-    "--ignore=src/packaging/_vendor"
-]
+exclude = ["docs/_build", "tests/manylinux/build-hello-world.sh", "tests/musllinux/build.sh", "tests/hello-world.c", "tests/__pycache__", "build/__pycache__"]
 
 
 [tool.coverage.run]
 branch = true
-omit = [
-    "*/_vendor/*"
-]
 
 [tool.coverage.report]
 exclude_lines = ["pragma: no cover", "@abc.abstractmethod", "@abc.abstractproperty"]
@@ -65,21 +57,12 @@ warn_unused_ignores = true
 module = ["_manylinux"]
 ignore_missing_imports = true
 
-[[tool.mypy.overrides]]
-module = ["packaging._vendor.*"]
-ignore_errors = true
-follow_imports = "skip"
-ignore_missing_imports = true
-
 [tool.ruff]
 src = ["src"]
 extend-exclude = [
-    "_vendor"
+    "src/packaging/licenses/spdx.py"
 ]
 
-[tool.ruff.lint.isort]
-known-third-party = ["packaging._vendor"]
-
 [tool.ruff.lint]
 extend-select = [
     "B",
@@ -114,10 +97,3 @@ ignore = [
     "ISC001",
     "ISC002",
 ]
-
-[tool.vendoring]
-destination = "src/packaging/_vendor/"
-requirements = "src/packaging/_vendor/vendor.txt"
-namespace = "packaging._vendor"
-
-protected-files = ["__init__.py", "README.rst", "vendor.txt"]