• 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: Arch Linux
• Poetry version: 1.1.7

• [tool.poetry]
  name = "testy"
  version = "0.1.0"
  description = ""
  authors = ["Test user"]
  
  [tool.poetry.dependencies]
  python = ">=3.7,<4.0"
  dgl = [
  	{ git = "https://github.com/dmlc/dgl.git", tag = "v0.7.0", markers = "sys_platform == 'linux'"},
  	{ version="^0.7", markers = "sys_platform == 'darwin'"}
  ]
  
  [build-system]
  requires = ["poetry-core>=1.0.0"]
  build-backend = "poetry.core.masonry.api"

Issue

When using this pyproject.toml, I get the following exception:

  TypeError

  expected string or bytes-like object

  at /usr/lib/python3.9/site-packages/poetry/core/utils/helpers.py:27 in canonicalize_name
       23│ _canonicalize_regex = re.compile(r"[-_]+")
       24│ 
       25│ 
       26│ def canonicalize_name(name):  # type: (str) -> str
    →  27│     return _canonicalize_regex.sub("-", name).lower()
       28│ 
       29│ 
       30│ def module_name(name):  # type: (str) -> str
       31│     return canonicalize_name(name).replace(".", "_").replace("-", "_")