Error with a certain version constraint format

[not522]

What pipdeptree version are you using?

2.17.0

Are you running pipdeptree in a virtual environment?

• Yes

Describe the problem

Thank you for developing a great library!

We use pipdeptree in our CIs, and it fails in v2.17.0 but passes in v2.16.2.
optuna/optuna-integration#109

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/packaging/requirements.py", line 35, in __init__
    parsed = _parse_requirement(requirement_string)
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/packaging/_parser.py", line 64, in parse_requirement
    return _parse_requirement(Tokenizer(source, rules=DEFAULT_RULES))
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/packaging/_parser.py", line 82, in _parse_requirement
    url, specifier, marker = _parse_requirement_details(tokenizer)
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/packaging/_parser.py", line 120, in _parse_requirement_details
    specifier = _parse_specifier(tokenizer)
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/packaging/_parser.py", line 210, in _parse_specifier
    with tokenizer.enclosing_tokens(
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/contextlib.py", line 142, in __exit__
    next(self.gen)
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/packaging/_tokenizer.py", line 187, in enclosing_tokens
    self.raise_syntax_error(
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/packaging/_tokenizer.py", line 165, in raise_syntax_error
    raise ParserSyntaxError(
packaging._tokenizer.ParserSyntaxError: Expected matching RIGHT_PARENTHESIS for LEFT_PARENTHESIS, after version specifier
    scikit-image (<0.[19](https://github.com/optuna/optuna-integration/actions/runs/8562392755/job/23465560814#step:7:20).0>=0.16.1) ; extra == 'all'
                 ~~~~~~~~^

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.10.14/x64/bin/pipdeptree", line 8, in <module>
    sys.exit(main())
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/pipdeptree/__main__.py", line 24, in main
    tree = PackageDAG.from_pkgs(pkgs)
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/pipdeptree/_models/dag.py", line 47, in from_pkgs
    for r in p.requires():
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/pipdeptree/_models/package.py", line 102, in requires
    req = Requirement(r)
  File "/opt/hostedtoolcache/Python/3.10.14/x64/lib/python3.10/site-packages/packaging/requirements.py", line 37, in __init__
    raise InvalidRequirement(str(e)) from e
packaging.requirements.InvalidRequirement: Expected matching RIGHT_PARENTHESIS for LEFT_PARENTHESIS, after version specifier
    scikit-image (<0.19.0>=0.16.1) ; extra == 'all'
                 ~~~~~~~~^

I guess that the cause of this error is the incorrect format of catalyst.
https://github.com/catalyst-team/catalyst/blob/v22.04/requirements/requirements-cv.txt#L3

scikit-image<0.19.0>=0.16.1

[kemzeb]

Thanks for the report! Looks like we need to handle invalid requirements in METADATA files.

I do think you're correct about catalyst causing the issue as I am seeing it being included as an extra in their setup.py. It looks like it's just missing a comma in the version specifier i.e. scikit-image (<0.19.0, >=0.16.1) ; extra == 'all'.

Your CI output also matches what I see in catalyst's METADATA:

. . .
Provides-Extra: all
Requires-Dist: scikit-image (<0.19.0>=0.16.1) ; extra == 'all'
. . .
Provides-Extra: cv
. . .
Requires-Dist: scikit-image (<0.19.0>=0.16.1) ; extra == 'cv'
. . .

I pip installed catalyst using the cv extra; it seems that for some reason pip is forgiving when given an invalid version specifier, as we can see here:

Collecting scikit-image<0.19.0>=0.16.1 (from catalyst[cv])
  Downloading scikit_image-0.18.3-cp38-cp38-manylinux_2_17_aarch64.manylinux2014_aarch64.whl.metadata (7.9 kB)

Now comes the question of how to handle this. With 2.17.0 we replaced most usages of pip internal API with importlib.metadata and packaging, and here we've clearly seen that packaging is not so forgiving when it comes to invalid requirements.

My current approach to solving this is given an invalid requirement, just simply warn the user that it is invalid and that it will be skipped (since we weren't able to parse it). I feel that it is the responsibility of the project maintainers to ensure that their requirement strings are valid. When I get the time, I'll take a gander at the related pip code to see if I can extract anything useful, but otherwise I'll just go with this approach unless there are better ideas!