pip 更新报错——You should consider upgrading via the ‘python.exe -m pip install --upgrade pip‘ command.

1.pip更新之前都是：python -m pip install --upgrade pip
2.但今天一直提示有错误，试过输入：python -m pip install --upgrade pip -i https://pypi.douban/simple
3.也试过删除形如pip-21.0.3.dist-info的文件夹，再输入python -m pip install --upgrade pip也是报错

4.后面发现了一行关键的报错语句：

#大概意思是：没有执行安装包的权限
#可以在指令中添加--user 参数或者检查本地文件夹的相关权限设置
ERROR: Could not install packages due to an OSError: [WinError 5] 拒绝访问。: 'C:\\Python39\\Lib\\site-packages\\pip\\__init__.py'
Consider using the `--user` option or check the permissions.

5.修改后尝试执行：pip install --user --upgrade pip
6.pip工具算是更新成功了，但这么多的警告我还是想弄掉
7.输入了：pip3 install pyinstaller -i https://pypi.tuna.tsinghua.edu/simple -U

8.关键报错在于：

 note: This error originates from a subprocess, and is likely not a problem with pip.
 #此错误源于子流程，可能不是pip的问题。
error: legacy-install-failure
#错误：旧版安装失败
× Encountered error while trying to install package.
╰─> future
note: This is an issue with the package mentioned above, not pip.
#注意：这是上述软件包的问题，而不是pip
hint: See above for output from the failure.#提示：有关故障的输出，请参见上文。
WARNING: Ignoring invalid distribution -p (c:\python39\lib\site-packages)
WARNING: Ignoring invalid distribution -1p (c:\python39\lib\site-packages)
WARNING: Ignoring invalid distribution -p (c:\python39\lib\site-packages)
WARNING: Ignoring invalid distribution -0p (c:\python39\lib\site-packages)
WARNING: Ignoring invalid distribution -ip (c:\python39\lib\site-packages)
WARNING: Ignoring invalid distribution - (c:\python39\lib\site-packages)