Update version of vendored dependency: packaging

[abravalheri]

Summary of changes

• Update version of vendored dependency: packaging
• Remove no longer necessary vendored dependency: pyparsing
• Adapt existing tests and implementation to deal with the fact that packaging>=23 is more strict
• As a side-effect of running tox -e vendor jaraco.context also got updated (since it was not a very different release I kept this update)
  • I manually reverted all the other vendored files that got accidentally updated

Related: #3722

(For anyone reviewing the PR, you can ignore all the */_vendor/* but vendored.txt files, since those were changed by an automate process).

Pull Request Checklist

• Changes have tests
• News fragment added in changelog.d/.
  (See documentation for details)

[mgorny]

Thanks a lot for doing this!

[abravalheri]

In this test, the exception raised by the new version of packaging is "less user friendly", they report an expected error for a missing 'y' key.

Since pkg_resources is discouraged, I believe it is easier to skip this test, rather than matching against a non-informative error message...

[abravalheri]

These examples are relevant to understand the difference in behaviour:

pip-run 'packaging==21' -- -c 'from packaging.markers import Marker; m = Marker(""" "3.5" < python_version < "3.9" """); print(m.evaluate())'
# Collecting packaging==21
#   Using cached packaging-21.0-py3-none-any.whl (40 kB)
# Collecting pyparsing>=2.0.2
#   Using cached pyparsing-3.0.9-py3-none-any.whl (98 kB)
# Installing collected packages: pyparsing, packaging
# Successfully installed packaging-21.0 pyparsing-3.0.9
# Traceback (most recent call last):
#   File "/tmp/pip-run-ayqz5stg/packaging/markers.py", line 278, in __init__
#     self._markers = _coerce_parse_result(MARKER.parseString(marker))
#   File "/tmp/pip-run-ayqz5stg/pyparsing/core.py", line 1141, in parse_string
#     raise exc.with_traceback(None)
# pyparsing.exceptions.ParseException: Expected string_end, found '<'  (at char 24), (line:1, col:25)

pip-run 'packaging==23' -- -c 'from packaging.markers import Marker; m = Marker(""" "3.5" < python_version < "3.9" """); print(m.evaluate())'                                                             :(
# Collecting packaging==23
#   Using cached packaging-23.0-py3-none-any.whl (42 kB)
# Installing collected packages: packaging
# Successfully installed packaging-23.0
# True

[dvzrv]

Can we please have a release with these changes? It blocks downstreams from updating python-packaging.

[jaraco]

Releasing as v67.