Error installing extras with dependencies using the arbitrary equality clause (===)

[xafilox]

System info

• pip version: 21.0.1
• Python version: 3.6.9
• Operating system: Linux INV03249 4.15.0-132-generic pip -E env freeze returns something half-correct. #136-Ubuntu SMP Tue Jan 12 14:58:42 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

What did you want to do?

Install a package (let's call it mypackage) with an extra (mu-metrics) that specifies a dependency (mu-client) using the arbitrary equality clause (===), that is pip install mypackage[mu-metrics]. Looking at the METADATA file in the dist_info folder of the wheel package everything seems fine and the requirement of mu-client from mu-metrics appears with the arbitrary equality clause.

Provides-Extra: documenter
Provides-Extra: mu-metrics
Requires-Dist: python-dateutil
Requires-Dist: dill (==0.2.8.1)
Requires-Dist: pandas (==0.23.4)
Requires-Dist: pyarrow (==0.14.1)
Requires-Dist: scipy (==1.3.2)
Requires-Dist: pyspark (<3.0.0,>=2.2.1)
Provides-Extra: documenter
Requires-Dist: sphinx (==3.2.1); extra == 'documenter'
Requires-Dist: networkx (==2.4); extra == 'documenter'
Requires-Dist: pygraphviz (==1.5); extra == 'documenter'
Requires-Dist: matplotlib; extra == 'documenter'
Requires-Dist: rinohtype (==0.4.2); extra == 'documenter'
Provides-Extra: mu-metrics
Requires-Dist: mu-client (===0.0.1); extra == 'mu-metrics'

Output

ERROR: Exception:
Traceback (most recent call last):
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3021, in _dep_map
    return self.__dep_map
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2815, in __getattr__
    raise AttributeError(attr)
AttributeError: _DistInfoDistribution__dep_map

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/packaging/requirements.py", line 113, in __init__
    req = REQUIREMENT.parseString(requirement_string)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 1955, in parseString
    raise exc
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 3814, in parseImpl
    raise ParseException(instring, loc, self.errmsg, self)
pip._vendor.pyparsing.ParseException: Expected stringEnd, found '('  (at char 10), (line:1, col:11)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3101, in __init__
    super(Requirement, self).__init__(requirement_string)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/packaging/requirements.py", line 117, in __init__
    requirement_string[e.loc : e.loc + 8], e.msg
pip._vendor.packaging.requirements.InvalidRequirement: Parse error at "'(===0.0.'": Expected stringEnd

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_internal/cli/base_command.py", line 189, in _main
    status = self.run(options, args)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_internal/cli/req_command.py", line 178, in wrapper
    return func(self, options, args)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_internal/commands/install.py", line 317, in run
    reqs, check_supported_wheels=not options.target_dir
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_internal/resolution/resolvelib/resolver.py", line 122, in resolve
    requirements, max_rounds=try_to_avoid_resolution_too_deep,
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/resolvelib/resolvers.py", line 453, in resolve
    state = resolution.resolve(requirements, max_rounds=max_rounds)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/resolvelib/resolvers.py", line 347, in resolve
    failure_causes = self._attempt_to_pin_criterion(name, criterion)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/resolvelib/resolvers.py", line 207, in _attempt_to_pin_criterion
    criteria = self._get_criteria_to_update(candidate)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/resolvelib/resolvers.py", line 198, in _get_criteria_to_update
    for r in self._p.get_dependencies(candidate):
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_internal/resolution/resolvelib/provider.py", line 172, in get_dependencies
    for r in candidate.iter_dependencies(with_requires)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_internal/resolution/resolvelib/provider.py", line 171, in <listcomp>
    r
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 527, in iter_dependencies
    valid_extras = self.extras.intersection(self.base.dist.extras)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2978, in extras
    return [dep for dep in self._dep_map if dep]
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3023, in _dep_map
    self.__dep_map = self._compute_dependencies()
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3033, in _compute_dependencies
    reqs.extend(parse_requirements(req))
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3094, in parse_requirements
    yield Requirement(line)
  File "/home/lauravera/workspace/venvs/attribute_generation/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3103, in __init__
    raise RequirementParseError(str(e))
pip._vendor.pkg_resources.RequirementParseError: Parse error at "'(===0.0.'": Expected stringEnd

[uranusjr]

See #9650 and pypa/packaging#336.

If you don’t mind, may I ask where did you learn about the operator (===)? It seems weird we got two issues on this in one day while practically nobody cared about this (except packaging nerds like myself) for more than five years…

[xafilox]

@uranusjr Sure, it's part of the pep 440, I found it there (https://www.python.org/dev/peps/pep-0440/#arbitrary-equality). I use it to avoid installing local versions :)

[uranusjr]

Thanks. That description has been there since PEP 440 became a thing, so maybe it is actually just a coincidence (hmm). I thought someone wrote/talked about this somewhere so it suddenly gained awareness to more people.

[atugushev]

@uranusjr see also another use-case: jazzband/pip-tools#1114