没有名为“pip._vendor.cachecontrol”的模块

Question

在 OSX 上运行 pip 会出现以下错误：

Traceback (most recent call last):
  File "/usr/local/bin/pip", line 9, in <module>
    load_entry_point('pip==6.0.6', 'console_scripts', 'pip')()
  File "build/bdist.macosx-10.10-x86_64/egg/pkg_resources/__init__.py", line 519, in load_entry_point
  File "build/bdist.macosx-10.10-x86_64/egg/pkg_resources/__init__.py", line 2630, in load_entry_point
  File "build/bdist.macosx-10.10-x86_64/egg/pkg_resources/__init__.py", line 2310, in load
  File "build/bdist.macosx-10.10-x86_64/egg/pkg_resources/__init__.py", line 2316, in resolve
  File "/usr/local/Cellar/python/2.7.7_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-6.0.6-py2.7.egg/pip/__init__.py", line 15, in <module>
    from pip.vcs import git, mercurial, subversion, bazaar  # noqa
  File "/usr/local/Cellar/python/2.7.7_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-6.0.6-py2.7.egg/pip/vcs/mercurial.py", line 11, in <module>
    from pip.download import path_to_url
  File "/usr/local/Cellar/python/2.7.7_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-6.0.6-py2.7.egg/pip/download.py", line 36, in <module>
    from pip._vendor.cachecontrol import CacheControlAdapter
  File "/usr/local/Cellar/python/2.7.7_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-6.0.6-py2.7.egg/pip/_vendor/__init__.py", line 81, in load_module
    raise ImportError("No module named '%s'" % (name,))
ImportError: No module named 'pip._vendor.cachecontrol'

知道我做错了什么吗？

Answer 1

不特定于 OSX，但对于那些正在处理这个问题的人来说，因为 Python 3.8.0 在大多数稳定的存储库中，这可能是因为您在更新包时出于兼容性原因保留了一个包，或者删除了一个必需的包。

就我而言，我已经删除了msgpack 包并计划重新安装它以解决另一个问题，但是删除该包后，我无法通过 pip 重新安装它。

解决方案是（重新）安装python-msgpack。

即对于 Arch 的默认包管理器：

sudo pacman -Sy python-msgpack

Answer 2

确保您的系统安装了 OpenSSL。

如果是 OSX，

$ brew install openssl

https://github.com/pypa/pip/issues/2345