Issue With Poetry 1.1.4 When Performing an Add

poetry add -D mypy

Using virtualenv: /Users/jwheeler/Library/Caches/pypoetry/virtualenvs/poetry-demo-esfPYa1_-py3.8
PyPI: No release information found for mypy-0.500, skipping
PyPI: 77 packages found for mypy *
Using version ^0.790 for mypy

Updating dependencies
Resolving dependencies...
   1: fact: poetry-demo is 0.1.0
   1: derived: poetry-demo
   1: fact: poetry-demo depends on pendulum (^2.1.2)
   1: fact: poetry-demo depends on pytest (^5.2)
   1: fact: poetry-demo depends on flake8 (^3.8.4)
   1: fact: poetry-demo depends on mypy (^0.790)
   1: fact: poetry-demo depends on pytest (^5.2)
   1: fact: poetry-demo depends on flake8 (^3.8.4)
   1: fact: poetry-demo depends on mypy (^0.790)
   1: selecting poetry-demo (0.1.0)
   1: derived: mypy (^0.790)
   1: derived: flake8 (^3.8.4)
   1: derived: pytest (^5.2)
   1: derived: pendulum (^2.1.2)
PyPI: No release information found for mypy-0.500, skipping
PyPI: 1 packages found for mypy >=0.790,<0.791
   1: fact: mypy (0.790) depends on typed-ast (>=1.4.0,<1.5.0)
   1: fact: mypy (0.790) depends on typing-extensions (>=3.7.4)
   1: fact: mypy (0.790) depends on mypy-extensions (>=0.4.3,<0.5.0)
   1: selecting mypy (0.790)
   1: derived: mypy-extensions (>=0.4.3,<0.5.0)
   1: derived: typing-extensions (>=3.7.4)
   1: derived: typed-ast (>=1.4.0,<1.5.0)
PyPI: 1 packages found for mypy-extensions >=0.4.3,<0.5.0
PyPI: 4 packages found for typing-extensions >=3.7.4
PyPI: 2 packages found for typed-ast >=1.4.0,<1.5.0
   1: fact: flake8 (3.8.4) depends on pyflakes (>=2.2.0,<2.3.0)
   1: fact: flake8 (3.8.4) depends on pycodestyle (>=2.6.0a1,<2.7.0)
   1: fact: flake8 (3.8.4) depends on mccabe (>=0.6.0,<0.7.0)
   1: selecting flake8 (3.8.4)
   1: derived: mccabe (>=0.6.0,<0.7.0)
   1: derived: pycodestyle (>=2.6.0a1,<2.7.0)
   1: derived: pyflakes (>=2.2.0,<2.3.0)
   1: fact: pytest (5.4.3) depends on py (>=1.5.0)
   1: fact: pytest (5.4.3) depends on packaging (*)
   1: fact: pytest (5.4.3) depends on attrs (>=17.4.0)
   1: fact: pytest (5.4.3) depends on more-itertools (>=4.0.0)
   1: fact: pytest (5.4.3) depends on pluggy (>=0.12,<1.0)
   1: fact: pytest (5.4.3) depends on wcwidth (*)
   1: fact: pytest (5.4.3) depends on atomicwrites (>=1.0)
   1: fact: pytest (5.4.3) depends on colorama (*)
   1: selecting pytest (5.4.3)
   1: derived: colorama (*)
   1: derived: atomicwrites (>=1.0)
   1: derived: wcwidth (*)
   1: derived: pluggy (>=0.12,<1.0)
   1: derived: more-itertools (>=4.0.0)
   1: derived: attrs (>=17.4.0)
   1: derived: packaging (*)
   1: derived: py (>=1.5.0)
   1: fact: pendulum (2.1.2) depends on python-dateutil (>=2.6,<3.0)
   1: fact: pendulum (2.1.2) depends on pytzdata (>=2020.1)
   1: selecting pendulum (2.1.2)
   1: derived: pytzdata (>=2020.1)
   1: derived: python-dateutil (>=2.6,<3.0)
   1: selecting mypy-extensions (0.4.3)
   1: selecting mccabe (0.6.1)
   1: selecting pycodestyle (2.6.0)
   1: selecting pyflakes (2.2.0)
   1: selecting colorama (0.4.4)
   1: selecting atomicwrites (1.4.0)
   1: selecting wcwidth (0.2.5)
   1: selecting pluggy (0.13.1)
   1: selecting more-itertools (8.6.0)
   1: selecting attrs (20.3.0)
   1: fact: packaging (20.4) depends on pyparsing (>=2.0.2)
   1: fact: packaging (20.4) depends on six (*)
   1: selecting packaging (20.4)
   1: derived: six (*)
   1: derived: pyparsing (>=2.0.2)
   1: selecting py (1.9.0)
   1: selecting pytzdata (2020.1)
   1: fact: python-dateutil (2.8.1) depends on six (>=1.5)
   1: selecting python-dateutil (2.8.1)
   1: derived: six (>=1.5)
   1: selecting six (1.15.0)
   1: selecting pyparsing (2.4.7)
PyPI: Getting info for typed-ast (1.4.1) from PyPI
PyPI: No dependencies found, downloading archives
PyPI: Downloading sdist: typed_ast-1.4.1.tar.gz
   1: Version solving took 0.175 seconds.
   1: Tried 1 solutions.

  Stack trace:

  26  ~/.poetry/lib/poetry/_vendor/py3.8/clikit/console_application.py:131 in run
       129│             parsed_args = resolved_command.args
       130│ 
     → 131│             status_code = command.handle(parsed_args, io)
       132│         except KeyboardInterrupt:
       133│             status_code = 1

  25  ~/.poetry/lib/poetry/_vendor/py3.8/clikit/api/command/command.py:120 in handle
       118│     def handle(self, args, io):  # type: (Args, IO) -> int
       119│         try:
     → 120│             status_code = self._do_handle(args, io)
       121│         except KeyboardInterrupt:
       122│             if io.is_debug():

  24  ~/.poetry/lib/poetry/_vendor/py3.8/clikit/api/command/command.py:171 in _do_handle
       169│         handler_method = self._config.handler_method
       170│ 
     → 171│         return getattr(handler, handler_method)(args, io, self)
       172│ 
       173│     def __repr__(self):  # type: () -> str

  23  ~/.poetry/lib/poetry/_vendor/py3.8/cleo/commands/command.py:92 in wrap_handle
        90│         self._command = command
        91│ 
     →  92│         return self.handle()
        93│ 
        94│     def handle(self):  # type: () -> Optional[int]

  22  ~/.poetry/lib/poetry/console/commands/add.py:174 in handle
       172│ 
       173│         try:
     → 174│             status = self._installer.run()
       175│         except Exception:
       176│             self.poetry.file.write(original_content)

  21  ~/.poetry/lib/poetry/installation/installer.py:103 in run
       101│         local_repo = Repository()
       102│ 
     → 103│         return self._do_install(local_repo)
       104│ 
       105│     def dry_run(self, dry_run=True):  # type: (bool) -> Installer

  20  ~/.poetry/lib/poetry/installation/installer.py:235 in _do_install
       233│             )
       234│ 
     → 235│             ops = solver.solve(use_latest=self._whitelist)
       236│         else:
       237│             self._io.write_line("Installing dependencies from lock file")

  19  ~/.poetry/lib/poetry/puzzle/solver.py:65 in solve
        63│         with self._provider.progress():
        64│             start = time.time()
     →  65│             packages, depths = self._solve(use_latest=use_latest)
        66│             end = time.time()
        67│ 

  18  ~/.poetry/lib/poetry/puzzle/solver.py:233 in _solve
       231│ 
       232│         try:
     → 233│             result = resolve_version(
       234│                 self._package, self._provider, locked=locked, use_latest=use_latest
       235│             )

  17  ~/.poetry/lib/poetry/mixology/__init__.py:7 in resolve_version
       5│     solver = VersionSolver(root, provider, locked=locked, use_latest=use_latest)
       6│ 
     → 7│     return solver.solve()
       8│ 

  16  ~/.poetry/lib/poetry/mixology/version_solver.py:84 in solve
        82│             while next is not None:
        83│                 self._propagate(next)
     →  84│                 next = self._choose_package_version()
        85│ 
        86│             return self._result()

  15  ~/.poetry/lib/poetry/mixology/version_solver.py:397 in _choose_package_version
       395│             version = locked
       396│ 
     → 397│         version = self._provider.complete_package(version)
       398│ 
       399│         conflict = False

  14  ~/.poetry/lib/poetry/puzzle/provider.py:433 in complete_package
       431│             package = DependencyPackage(
       432│                 package.dependency,
     → 433│                 self._pool.package(
       434│                     package.name,
       435│                     package.version.text,

  13  ~/.poetry/lib/poetry/repositories/pool.py:135 in package
       133│             for idx, repo in enumerate(self._repositories):
       134│                 try:
     → 135│                     package = repo.package(name, version, extras=extras)
       136│                 except PackageNotFound:
       137│                     continue

  12  ~/.poetry/lib/poetry/repositories/pypi_repository.py:158 in package
       156│         extras=None,  # type: (Union[list, None])
       157│     ):  # type: (...) -> Package
     → 158│         return self.get_release_info(name, version).to_package(name=name, extras=extras)
       159│ 
       160│     def search(self, query):

  11  ~/.poetry/lib/poetry/repositories/pypi_repository.py:223 in get_release_info
       221│             return PackageInfo.load(self._get_release_info(name, version))
       222│ 
     → 223│         cached = self._cache.remember_forever(
       224│             "{}:{}".format(name, version), lambda: self._get_release_info(name, version)
       225│         )

  10  ~/.poetry/lib/poetry/_vendor/py3.8/cachy/repository.py:174 in remember_forever
       172│             return val
       173│ 
     → 174│         val = value(callback)
       175│ 
       176│         self.forever(key, val)

   9  ~/.poetry/lib/poetry/_vendor/py3.8/cachy/helpers.py:6 in value
       4│ def value(val):
       5│     if callable(val):
     → 6│         return val()
       7│ 
       8│     return val

   8  ~/.poetry/lib/poetry/repositories/pypi_repository.py:224 in <lambda>
       222│ 
       223│         cached = self._cache.remember_forever(
     → 224│             "{}:{}".format(name, version), lambda: self._get_release_info(name, version)
       225│         )
       226│ 

   7  ~/.poetry/lib/poetry/repositories/pypi_repository.py:304 in _get_release_info
       302│                 return data.asdict()
       303│ 
     → 304│             info = self._get_info_from_urls(urls)
       305│ 
       306│             data.requires_dist = info.requires_dist

   6  ~/.poetry/lib/poetry/repositories/pypi_repository.py:419 in _get_info_from_urls
       417│                 return self._get_info_from_wheel(platform_specific_wheels[0])
       418│ 
     → 419│         return self._get_info_from_sdist(urls["sdist"][0])
       420│ 
       421│     def _get_info_from_wheel(self, url):  # type: (str) -> PackageInfo

   5  ~/.poetry/lib/poetry/repositories/pypi_repository.py:447 in _get_info_from_sdist
       445│             self._download(url, str(filepath))
       446│ 
     → 447│             return PackageInfo.from_sdist(filepath)
       448│ 
       449│     def _download(self, url, dest):  # type: (str, str) -> None

   4  ~/.poetry/lib/poetry/inspection/info.py:561 in from_sdist
       559│         """
       560│         if path.is_file():
     → 561│             return cls._from_sdist_file(path=path)
       562│ 
       563│         # if we get here then it is neither an sdist instance nor a file

   3  ~/.poetry/lib/poetry/inspection/info.py:291 in _from_sdist_file
       289│ 
       290│             # now this is an unpacked directory we know how to deal with
     → 291│             new_info = cls.from_directory(path=sdist_dir)
       292│ 
       293│         if not info:

   2  ~/.poetry/lib/poetry/inspection/info.py:541 in from_directory
       539│                         info = cls.from_setup_files(path)
       540│                     else:
     → 541│                         info = cls._pep517_metadata(path)
       542│                 except PackageInfoError:
       543│                     if not info:

   1  ~/.poetry/lib/poetry/inspection/info.py:506 in _pep517_metadata
       504│                     )
       505│                 finally:
     → 506│                     os.chdir(cwd.as_posix())
       507│ 
       508│         if info:

  RuntimeError

  generator didn't stop after throw()

  at ~/.pyenv/versions/3.8.2/lib/python3.8/contextlib.py:162 in __exit__
      158│                 # by 'except BaseException'.
      159│                 if sys.exc_info()[1] is value:
      160│                     return False
      161│                 raise
    → 162│             raise RuntimeError("generator didn't stop after throw()")
      163│ 
      164│ 
      165│ class _AsyncGeneratorContextManager(_GeneratorContextManagerBase,
      166│                                     AbstractAsyncContextManager):

pyproject.toml

[tool.poetry]
name = "poetry-demo"
version = "0.1.0"
description = ""
authors = ["jwheeler31 <email>"]

[tool.poetry.dependencies]
python = "^3.8"
pendulum = "^2.1.2"

[tool.poetry.dev-dependencies]
pytest = "^5.2"
flake8 = "^3.8.4"

[build-system]
requires = ["poetry-core>=1.0.0"]
build-backend = "poetry.core.masonry.api"