PIP给出一个属性：模块＆＃x27;键入＆＃x27;没有属性＆＃x27; _classvar＆＃x27;

Question

我在Windows 10系统上的PIP遇到了麻烦。如果我尝试使用PIP做任何事情（例如“ PIP -H”），我会得到以下内容：

D:\Downloads\pip\pip-22.0.4>pip -h
Traceback (most recent call last):
  File "C:\Program Files\Python310\Scripts\pip-script.py", line 33, in <module>
    sys.exit(load_entry_point('pip==22.0.4', 'console_scripts', 'pip')())
  File "C:\Program Files\Python310\Scripts\pip-script.py", line 25, in importlib_load_entry_point
    return next(matches).load()
  File "C:\Program Files\Python310\lib\importlib\metadata\__init__.py", line 171, in load
    module = import_module(match.group('module'))
  File "C:\Program Files\Python310\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python39\Lib\site-packages\pip\_internal\cli\main.py", line 9, in <module>
    from pip._internal.cli.autocompletion import autocomplete
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python39\Lib\site-packages\pip\_internal\cli\autocompletion.py", line 10, in <module>
    from pip._internal.cli.main_parser import create_main_parser
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python39\Lib\site-packages\pip\_internal\cli\main_parser.py", line 8, in <module>
    from pip._internal.cli import cmdoptions
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python39\Lib\site-packages\pip\_internal\cli\cmdoptions.py", line 23, in <module>
    from pip._internal.cli.parser import ConfigOptionParser
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python39\Lib\site-packages\pip\_internal\cli\parser.py", line 12, in <module>
    from pip._internal.configuration import Configuration, ConfigurationError
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python39\Lib\site-packages\pip\_internal\configuration.py", line 20, in <module>
    from pip._internal.exceptions import (
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python39\Lib\site-packages\pip\_internal\exceptions.py", line 14, in <module>
    from pip._vendor.rich.console import Console, ConsoleOptions, RenderResult
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python39\Lib\site-packages\pip\_vendor\rich\console.py", line 55, in <module>
    from .pretty import Pretty, is_expandable
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python39\Lib\site-packages\pip\_vendor\rich\pretty.py", line 366, in <module>
    class Node:
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python36\Lib\site-packages\dataclasses.py", line 958, in dataclass
    return wrap(_cls)
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python36\Lib\site-packages\dataclasses.py", line 950, in wrap
    return _process_class(cls, init, repr, eq, order, unsafe_hash, frozen)
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python36\Lib\site-packages\dataclasses.py", line 800, in _process_class
    cls_fields = [_get_field(cls, name, type)
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python36\Lib\site-packages\dataclasses.py", line 800, in <listcomp>
    cls_fields = [_get_field(cls, name, type)
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python36\Lib\site-packages\dataclasses.py", line 659, in _get_field
    if (_is_classvar(a_type, typing)
  File "C:\Users\jxcla\AppData\Local\Programs\Python\Python36\Lib\site-packages\dataclasses.py", line 550, in _is_classvar
    return type(a_type) is typing._ClassVar
AttributeError: module 'typing' has no attribute '_ClassVar'. Did you mean: 'ClassVar'?

我不确定何时开始发生，并且我尝试以多种方式重新安装PIP，但没有运气。相同的错误。我已经在网络上搜索了答案，但是没有任何东西可以为我解决。

当涉及到这一点时，我有点菜鸟，所以完全有可能我做了一些事情来加强作品。任何帮助将不胜感激。

约翰

Answer 1

在我的几个CI构建中，这个问题似乎正在为我兴起。一种可能的 fix似乎是：

pip uninstall dataclasses -y

在我的情况下，我没有知道dataclasses如何安装（应该是内置的不是依赖项），但是昨晚我解开依赖项scs时失败了。