Changelog for python3-packaging: 26.2 -> 26.3
Source: CHANGELOG.rst

26.3 - 2026-08-03
~~~~~~~~~~~~~~~~~

Features:

* Add a public :class:`~packaging.ranges.VersionRange` API and
  :meth:`SpecifierSet.to_range() <packaging.specifiers.SpecifierSet.to_range>`,
  representing the versions a specifier set accepts as an interval set that
  supports intersection, union, difference, complement, set relations,
  membership tests, and filtering.
  :meth:`~packaging.ranges.VersionRange.to_specifier_set` converts a range back
  to a :class:`~packaging.specifiers.SpecifierSet` where a PEP 440 form exists.
  (:pull:`1267`, :pull:`1270`, :pull:`1298`)
* PEP 808: accept ``Metadata-Version: 2.6``. (:pull:`1194`)
* Add a ``limit`` argument to ``parse_tag()`` for compressed tag sets.
  (:issue:`1220`)
* Add a ``prefer_sdist_predicate`` argument to ``Pylock.select()`` to prefer
  source distributions over wheels for selected packages. (:pull:`1334`)
* Add :func:`~packaging.tags.pure_python_tags` to generate the pure-Python
  tags for a Python version without touching the running platform.
  (:pull:`1346`)
* Add :meth:`SpecifierSet.is_subset()
  <packaging.specifiers.SpecifierSet.is_subset>`, :meth:`~packaging.specifiers.SpecifierSet.is_superset`,
  and :meth:`~packaging.specifiers.SpecifierSet.is_disjoint`, which compare the
  versions two specifier sets accept. (:pull:`1313`)

Behavior adaptations:

* Drop support for Python 3.8; packaging now requires Python 3.9 or later.
  (:pull:`1157`)
* Prefer native ``linux_*`` platform tags over ``manylinux`` and ``musllinux``
  tags on Linux. (:issue:`160`)

Fixes for versions and specifiers:

* Raise ``InvalidVersion`` instead of ``TypeError`` when ``Version`` is given a
  non-string. (:pull:`1319`)
* Raise ``InvalidVersion`` for non-string pre-release letters passed to
  ``Version.from_parts``. (:pull:`1241`)
* Fix an ``AttributeError`` when hashing internally trimmed versions.
  (:pull:`1242`)
* Fix ``SpecifierSet.is_unsatisfiable`` for post-release boundary
  intersections. (:pull:`1257`)

Fixes for requirements and markers:

* Make ``Requirement.__hash__`` consistent with ``__eq__`` for
  trailing-zero-equivalent specifiers (e.g. ``foo==1.0.0`` and
  ``foo==1.0.0.0``), so equal requirements hash equal and deduplicate in
  sets and dicts. (:pull:`1232`)
* Normalize requested extra names before comparing or hashing requirements.
  (:issue:`644`)
* Preserve a ``Requirement``'s specifier ``prereleases`` override across a
  pickle round trip. (:issue:`1204`)
* Raise ``InvalidRequirement`` instead of ``InvalidSpecifier`` when a
  requirement contains an invalid specifier. (:pull:`1332`)
* Clarify the error for post-release prefix wildcards like ``==1.0.post1.*``.
  (:pull:`1299`)
* Preserve quoting semantics when serializing marker values, so round-tripped
  markers parse back to the same marker. (:pull:`1213`)
* Keep the parentheses of a nested group when serializing markers.
  (:pull:`1316`)
* Normalize ``extra`` and ``dependency_groups`` values in nested markers at
  parse time. (:pull:`1246`, :pull:`1310`)
* Raise ``UndefinedComparison`` when a set-valued variable like ``extras`` is
  used outside the membership form. (:pull:`1265`)
* Raise ``UndefinedEnvironmentName`` (a ``KeyError`` subclass) for missing
  environment keys during marker evaluation. (:pull:`1276`)
* Wrap malformed string literal errors in ``InvalidMarker`` /
  ``InvalidRequirement`` instead of leaking a low-level error. (:pull:`1249`)
* Reject requirements and markers with a trailing line break. (:pull:`1345`)

Fixes for metadata and licenses:

* Collect all ``from_email`` validation errors into one ``ExceptionGroup``
  instead of raising the first. (:pull:`1268`)
* Accept the UTF-8 charset case-insensitively in email payloads.
  (:pull:`1330`)
* Reject malformed ``Description-Content-Type`` values. (:pull:`1329`)
* Don't rewrite user values that contain ``{field}`` placeholders in error
  messages. (:pull:`1327`)
* Route multipart email payloads to ``unparsed`` instead of asserting.
  (:pull:`1247`)
* Make ``InvalidMetadata`` and ``CyclicDependencyGroup`` picklable.
  (:pull:`1328`)
* Fold every line boundary ``str.splitlines`` recognizes when writing a header
  with :class:`~packaging.metadata.RFC822Message`. (:pull:`1356`)
* Raise ``InvalidLicenseExpression`` for misplaced ``WITH`` clauses and empty
  ``LicenseRef-`` names. (:pull:`1266`)
* Raise ``InvalidLicenseExpression`` instead of ``KeyError`` for a
  ``LicenseRef-`` with a ``+`` suffix. (:pull:`1219`)

Fixes for tags and filenames:

* Raise ``InvalidTag`` from ``parse_tag()`` for tags with the wrong number of
  components. (:pull:`1238`)
* Reject empty tag components in ``parse_wheel_filename()`` and
  ``parse_tag()``. (:pull:`1234`)
* Reject an empty project name in the wheel and sdist filename parsers.
  (:pull:`1305`)
* Reject wheel filenames with a trailing newline. (:pull:`1341`)
* Reject wheel tags whose interpreter component is not an identifier.
  (:issue:`577`)
* ``is_normalized_name`` now rejects names with collapsed double hyphens like
  ``a--b``. (:pull:`1230`)
* Fix duplicate explicit ``abi3t`` tags. (:pull:`1245`)
* Forward the ``warn`` argument to ``generic_tags()`` in ``sys_tags()``.
  (:pull:`1264`)
* Raise ``SystemError`` for an empty or malformed CPython ``EXT_SUFFIX``.
  (:pull:`1271`, :pull:`1301`)
* Fix a typo in the macOS ``fat3`` architecture name (was ``fat32``).
  (:pull:`1199`)

Fixes for pylock, direct URLs, and dependency groups:

* Percent-decode ``pylock`` artifact file names derived from a ``url`` so that
  local versions (e.g. a wheel with ``2.12.1+cu130`` encoded as ``2.12.1%2Bcu130``)
  yield a valid file name. (:pull:`1314`)
* Use an explicitly empty ``tags`` sequence in ``Pylock.select()`` instead of
  falling back to ``sys_tags()``. (:pull:`1349`)
* Fix ``Pylock.select()`` on Python builds that report a non-PEP 440
  ``python_full_version`` (e.g. ``3.15.0+``). (:pull:`1179`)
* Reject TOML booleans where integers are expected in ``pylock`` files.
  (:pull:`1244`)
* Add ``PylockSelectError`` to ``packaging.pylock.__all__``. (:pull:`1202`)
* Fix ``DirectUrl`` credential stripping for passwords containing ``@``.
  (:pull:`1218`)
* Parse the URL scheme case-insensitively when checking for file URLs in
  ``direct_url``. (:pull:`1240`)
* Require absolute file URLs for local directories in ``direct_url``.
  (:pull:`1297`)
* Collect ``InvalidRequirement`` errors while resolving dependency groups
  instead of leaking them. (:pull:`1302`)
* Don't cache malformed dependency group parses. (:pull:`1248`)

Performance:

* Implement ``Specifier`` and ``SpecifierSet`` filtering with the new range
  engine. (:pull:`1120`, :pull:`1259`)
* Cache the default marker environment. (:pull:`1250`)
* Cache the ``_manylinux`` module lookup process-wide. (:pull:`1254`)
* Add ``__slots__`` to ``Requirement`` and the token classes. (:pull:`1320`,
  :pull:`1258`)
* Keep range caches across canonicalization, precompile the wheel project-name
  pattern, simplify ``parse_tag()``, and skip ``platform.mac_ver()`` when the
  version and arch are given. (:pull:`1253`, :pull:`1256`, :pull:`1236`,
  :pull:`1255`)

Documentation:

* Describe the validation scope of ``packaging.pylock``. (:pull:`1339`)
* Explain which ``packaging.metadata`` fields are validated. (:pull:`1342`)
* Document ``RFC822Policy`` in the low-level ``packaging.metadata`` interface.
  (:pull:`1222`)
* Enable nitpicky mode and render missing classes and fields in the API
  reference. (:pull:`1196`, :pull:`1225`, :pull:`1277`)
* Add missing ``versionadded`` / ``versionchanged`` directives and many small
  docstring fixes across the API reference. (:pull:`1205`, :pull:`1207`,
  :pull:`1208`, :pull:`1209`, :pull:`1211`, :pull:`1216`, :pull:`1217`,
  :pull:`1223`, :pull:`1272`, :pull:`1273`, :pull:`1274`, :pull:`1291`,
  :pull:`1300`, :pull:`1303`, :pull:`1317`, :pull:`1344`)

Internal:

* Add Python 3.15 to the test matrix. (:pull:`1190`)
* Add a musl/Alpine test job and make the test suite pass on musl.
  (:pull:`1226`, :pull:`1227`)
* Expand the downstream test matrix by ten projects. (:pull:`1261`)
* Update to mypy 2. (:pull:`1191`)
* Use nox's uv integration. (:pull:`1057`)

* Re-export ``ExceptionGroup`` in metadata for now in (:pull:`1164`)
* Fix a ``DirectUrl`` typo in (:pull:`1169`)
* Test new pickle guarantees in (:pull:`1174`)
* PEP 735: add ``packaging.dependency_groups`` module, based on the ``dependency-groups`` package in (:pull:`1065`)