[InvalidRequirement] Invalid requirement, parse error at "'extra =='"

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

• OS version and name: maxOS 10.15
• Poetry version: 1.0.5

Issue

When I run:

poetry add git+https://github.com/huggingface/transformers.git#a21d4fa410dc3b4c62f93aa0e6bbe4b75a101ee9 -vvv

The following exception is thrown:

[InvalidRequirement]
Invalid requirement, parse error at "'extra =='"

Traceback (most recent call last):
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/vendor/lib/python3.7/site-packages/clikit/console_application.py", line 131, in run
    status_code = command.handle(parsed_args, io)
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/vendor/lib/python3.7/site-packages/clikit/api/command/command.py", line 120, in handle
    status_code = self._do_handle(args, io)
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/vendor/lib/python3.7/site-packages/clikit/api/command/command.py", line 171, in _do_handle
    return getattr(handler, handler_method)(args, io, self)
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/vendor/lib/python3.7/site-packages/cleo/commands/command.py", line 92, in wrap_handle
    return self.handle()
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/lib/python3.7/site-packages/poetry/console/commands/add.py", line 89, in handle
    packages, allow_prereleases=self.option('allow-prereleases')
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/lib/python3.7/site-packages/poetry/console/commands/init.py", line 293, in _determine_requirements
    requires = self._parse_requirements(requires)
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/lib/python3.7/site-packages/poetry/console/commands/init.py", line 381, in _parse_requirements
    "git", url.url, reference=pair.get("rev")
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/lib/python3.7/site-packages/poetry/puzzle/provider.py", line 204, in get_package_from_vcs
    package = cls.get_package_from_directory(tmp_dir, name=name)
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/lib/python3.7/site-packages/poetry/puzzle/provider.py", line 412, in get_package_from_directory
    dep = dependency_from_pep_508(req)
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/lib/python3.7/site-packages/poetry/packages/__init__.py", line 39, in dependency_from_pep_508
    req = Requirement(name)
  File "/usr/local/Cellar/poetry/1.0.5_1/libexec/lib/python3.7/site-packages/poetry/version/requirements.py", line 212, in __init__
    requirement_string[e.loc : e.loc + 8]

If I try to add the package manually to the pyproject.toml file as follows:

transformers = {git = "https://github.com/huggingface/transformers.git", rev = "a21d4fa410dc3b4c62f93aa0e6bbe4b75a101ee9"}

The following exception is thrown instead:

[SolverProblemError]
Because text2error depends on transformers (*) which doesn't exist, version solving failed.

Ref https://github.com/huggingface/transformers/issues/3982

[abn]

Yes please.

[simonepri]

The root issue is definitely the grammar

I think the reason why the grammar behaves like that is because of the following example, that should be a valid url:

poetry @ git+https://github.com/python-poetry/poetry.git@b;ar; ; extra == "foo;"

But then in the str method they do not add the space back after the marker. https://github.com/pypa/packaging/blob/61672bf9f507f38e84ce2786a1c42f55fa0a3153/packaging/requirements.py#L139

I was actually wrong, they do add the space when they stringify the object, the thing is that they only do that for URLs.

https://github.com/pypa/packaging/blob/61672bf9f507f38e84ce2786a1c42f55fa0a3153/packaging/requirements.py#L136