Poetry: Python restricted dependencies for multiple Python versions fail: 'Array' object has no attribute 'strip'

[okin]

• [x] I am on the latest Poetry version.
• [x] I have searched the issues of this repo and believe that this is not a duplicate.
• [x] If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Ubuntu 18.10
• Poetry version: Poetry 0.12.11 (bug does also affect 0.12.10)
• Link of a Gist with the contents of your pyproject.toml file: https://gist.github.com/okin/9fca594f2a4ba9917f1c292752d21e4c

Issue

I want to configure an dependency that is only applied when specific Python versions are used.
The documentation shows an example that matches my case: pathlib2 = { version = "^2.2", python = ["~2.7", "^3.2"] }

I added this to my project config.
Whenever I now try to run poetry install, poetry update or poetry check I am greeted with the following message:

[AttributeError]            
'Array' object has no attribute 'strip'  

No further action is done as poetry appears to break in this case.

Debug output from poetry check

[AttributeError]            
'Array' object has no attribute 'strip'  

Exception trace:
 /home/wenselowski/.poetry/lib/poetry/_vendor/py3.6/cleo/application.py in run() at line 94
   status_code = self.do_run(input_, output_)
 /home/wenselowski/.poetry/lib/poetry/console/application.py in do_run() at line 88
   return super(Application, self).do_run(i, o)
 /home/wenselowski/.poetry/lib/poetry/_vendor/py3.6/cleo/application.py in do_run() at line 197
   status_code = command.run(input_, output_)
 /home/wenselowski/.poetry/lib/poetry/console/commands/command.py in run() at line 77
   return super(BaseCommand, self).run(i, o)
 /home/wenselowski/.poetry/lib/poetry/_vendor/py3.6/cleo/commands/base_command.py in run() at line 146
   status_code = self.execute(input_, output_)
 /home/wenselowski/.poetry/lib/poetry/_vendor/py3.6/cleo/commands/command.py in execute() at line 107
   return self.handle()
 /home/wenselowski/.poetry/lib/poetry/console/commands/check.py in handle() at line 13
   check_result = self.poetry.check(self.poetry.local_config, strict=True)
 /home/wenselowski/.poetry/lib/poetry/console/commands/command.py in poetry() at line 62
   return self.get_application().poetry
 /home/wenselowski/.poetry/lib/poetry/console/application.py in poetry() at line 60
   self._poetry = Poetry.create(os.getcwd())
 /home/wenselowski/.poetry/lib/poetry/poetry.py in create() at line 148
   package.add_dependency(name, constraint)
 /home/wenselowski/.poetry/lib/poetry/packages/package.py in add_dependency() at line 304
   dependency.python_versions = python_versions
 /home/wenselowski/.poetry/lib/poetry/packages/dependency.py in python_versions() at line 89
   self._python_constraint = parse_constraint(value)
 /home/wenselowski/.poetry/lib/poetry/semver/__init__.py in parse_constraint() at line 19
   or_constraints = re.split(r"\s*\|\|?\s*", constraints.strip())

check

Workaround

No error is shown when configuring it as multiple requirements but no further testing was done if this actually would resolve correctly.

pathlib2 = [
    { version = "^2.2", python = "~2.7" },
    { version = "^2.2", python = "^3.2" }
]

[AntoineCezar]

I think pathlib2 = { version = "^2.2", python = "~2.7 || ^3.2" } sould work.

[sklarsa]

I'm experiencing the same behavior. Is this a temporary or permanent solution?

[dbarrosop]

Just ran into this one, I think this should either be fixed or the docs should be fixed as one of the examples is:

[tool.poetry.dependencies]
pathlib2 = { version = "^2.2", python = ["~2.7", "^3.2"] }

which leads to this issue.

[webartifex]

I can confirm this issue still exists

[stephsamson]

@webartifex does using the double pipe fix your issue?

[webartifex]

Hi @stephsamson , I was in your tutorial at Pycon.de :)

Regarding the fix, I chose not to support an older Python version in my project so I have no need for the double pipe any more. However, it is good that you put it in the docs. It was definitely missing there.

Thanks for your time.