Warnings traced when installed with pyparsing 2.4.1

[chrahunt]

This impacts packaging 19.0.

Issue: Importing packaging.requirements outputs warnings

Expected: Importing packaging.requirements does not output warnings

Context: pyparsing 2.4.1 was released yesterday and unfortunately caused our CI runs to fail because of the warning output to stdout on invocation of tox (which internally imports packaging.requirements). See pypa/pip#6767.

To reproduce:

$ docker run --rm -it python:3.6 bash -xc 'pip install packaging && python -c "import packaging.requirements"'
+ pip install packaging
Collecting packaging
  Downloading https://files.pythonhosted.org/packages/91/32/58bc30e646e55eab8b21abf89e353f59c0cc02c417e42929f4a9546e1b1d/packaging-19.0-py2.py3-none-any.whl
Collecting pyparsing>=2.0.2 (from packaging)
  Downloading https://files.pythonhosted.org/packages/9f/dc/b205465a60baca8e04a1555a84d9c79f910661765056f071fb6fc2db4841/pyparsing-2.4.1-py2.py3-none-any.whl (65kB)
     |████████████████████████████████| 71kB 15.3MB/s
Collecting six (from packaging)
  Downloading https://files.pythonhosted.org/packages/73/fb/00a976f728d0d1fecfe898238ce23f502a721c0ac0ecfedb80e0d88c64e9/six-1.12.0-py2.py3-none-any.whl
Installing collected packages: pyparsing, six, packaging
Successfully installed packaging-19.0 pyparsing-2.4.1 six-1.12.0
+ python -c 'import packaging.requirements'
/usr/local/lib/python3.6/site-packages/packaging/requirements.py:57: UserWarning: warn_ungrouped_named_tokens_in_collection: setting results name 'specifier' on And expression collides with '_original_end' on contained expression
  VERSION_SPEC = originalTextFor(_VERSION_SPEC)("specifier")
/usr/local/lib/python3.6/site-packages/packaging/requirements.py:60: UserWarning: warn_ungrouped_named_tokens_in_collection: setting results name 'marker' on And expression collides with '_original_end' on contained expression
  MARKER_EXPR = originalTextFor(MARKER_EXPR())("marker")

Available workarounds:

Either pin pyparsing to 2.4.0 or set the warnings filter to include ignore:warn_ungrouped_named_tokens_in_collection (e.g. PYTHONWARNINGS=ignore:warn_ungrouped_named_tokens_in_collection).

[chrahunt]

Related to tox-dev/tox#1375.

[paulmcg-iio]

Pyparsing 2.4.2 (pushed to PyPI this evening) disables these warnings by default

[pradyunsg]

Awesome! I'll close this then.

[ssbarnea]

Thanks! I wonder if it would not worth even hiding the 2.4.1 version from pypi.

[fungi]

Pyparsing 2.4.2 (pushed to PyPI this evening) disables these warnings by default

Pyparsing 3.0.0 (released an hour ago) un-hid this again when warnings are enabled in the interpreter, so it might be worth reopening the issue if this indicates a problem which should be fixed. It's not entirely clear to me why pyparsing objects to the implementation in packaging.requirements however.

Also, it's likely enhancement #468 will make it irrelevant if that's the direction packaging goes in.

[CAM-Gerlach]

I can confirm this, and in particular, this causes builds with python -W error -m build to fail across our CIs, which is rather problematic.

[fungi]

According to pyparsing/pyparsing#110 it will be fixed in pyparsing 3.0.5 (not yet released).

[fungi]

pyparsing 3.0.5 was released today correcting this.