安装ikpy库提示缺失setup.py及pip相关报错如何解决？

我想要使用pip安装ikpy库，但pip抛出了如下错误：

Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    IOError: [Errno 2] No such file or directory: '/tmp/pip-build-oYTjdr/ikpy/setup.py'

我从报错中判断pip找不到setup.py，因为该库使用的是setup.cfg配置文件。我尝试升级pip又出现了其他报错：

$ pip install --upgrade pip
Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-build-KCnfi9/pip/setup.py", line 7
        def read(rel_path: str) -> str:
                         ^
    SyntaxError: invalid syntax

我也尝试了用pip3安装，同样报错：

$ pip3 install ikpy
ModuleNotFoundError: No module named 'pip._vendor.pkg_resources'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/pip3", line 9, in <module>
    from pip import main
  File "/usr/lib/python3/dist-packages/pip/__init__.py", line 13, in <module>
    from pip.exceptions import InstallationError, CommandError, PipError
  File "/usr/lib/python3/dist-packages/pip/exceptions.py", line 6, in <module>
    from pip._vendor.six import iteritems
  File "/usr/lib/python3/dist-packages/pip/_vendor/__init__.py", line 75, in <module>
    vendored("pkg_resources")
  File "/usr/lib/python3/dist-packages/pip/_vendor/__init__.py", line 36, in vendored
    __import__(modulename, globals(), locals(), level=0)
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 668, in _load_unlocked
  File "<frozen importlib._bootstrap>", line 638, in _load_backward_compatible
  File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2927, in <module>
  File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2913, in _call_aside
  File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2952, in _initialize_master_working_set
  File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 956, in subscribe
  File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2952, in <lambda>
  File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2515, in activate
  File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2097, in declare_namespace
  File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2047, in _handle_ns
  File "/usr/share/python-wheels/pkg_resources-0.0.0-py2.py3-none-any.whl/pkg_resources/__init__.py", line 2066, in _rebuild_mod_path
AttributeError: '_NamespacePath' object has no attribute 'sort'

对应运行环境为Python 3.7.10，python3-pip版本为8.1.1-2ubuntu0.6。

解决方法 #

执行以下命令即可修复问题，修复后可正常使用pip3安装对应库：

curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
python3 get-pip.py 
pip3 install --upgrade setuptools

内容的提问来源于stack exchange，提问作者Meric Ozcan