在 Homebrew Python 2.7 安装中升级 pip 的问题

Question

我已经在我的 Mac 上使用 Homebrew 安装了 Python 2.7.9，而且 Homebrew 也安装了 pip。我的 Mac 上默认安装了一个旧的、未使用的 Python 版本。

问题是，当我尝试升级 pip（使用pip install --upgrade pip）时，pip 似乎想要升级较旧的默认 Python 版本附带的 pip 版本。以下是发生的情况（在全新安装 Python 2.7.9 后，即 brew remove python 后跟 brew install python）：

$ pip -V
pip 6.0.7 from /usr/local/Cellar/python/2.7.9/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip-6.0.7-py2.7.egg (python 2.7)

以上似乎是正确的。但是，会发生以下情况：

$ pip install --upgrade pip
You are using pip version 6.0.7, however version 6.0.8 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Collecting pip from https://pypi.python.org/packages/py2.py3/p/pip/pip-6.0.8-py2.py3-none-any.whl#md5=41e73fae2c86ba2270ff51c1d86f7e09
  Using cached pip-6.0.8-py2.py3-none-any.whl
Installing collected packages: pip
  Found existing installation: pip 6.0.7
    Uninstalling pip-6.0.7:
      Successfully uninstalled pip-6.0.7

Successfully installed pip-1.4.1

为什么要安装 pip 1.4.1？现在我明白了：

$ pip -V
pip 1.4.1 from /Library/Python/2.7/site-packages/pip-1.4.1-py2.7.egg (python 2.7)

这似乎对应于较旧的默认 Python 版本。当我再次尝试升级时，它失败了：

$ pip install --upgrade pip
Downloading/unpacking pip from https://pypi.python.org/packages/source/p/pip/pip-6.0.8.tar.gz#md5=2332e6f97e75ded3bddde0ced01dbda3
  Downloading pip-6.0.8.tar.gz (1.2MB): 1.2MB downloaded
  Running setup.py egg_info for package pip

    warning: no previously-included files found matching '.coveragerc'
    warning: no previously-included files found matching '.mailmap'
    warning: no previously-included files found matching '.travis.yml'
    warning: no previously-included files found matching 'pip/_vendor/Makefile'
    warning: no previously-included files found matching 'tox.ini'
    warning: no previously-included files found matching 'dev-requirements.txt'
    no previously-included directories found matching '.travis'
    no previously-included directories found matching 'docs/_build'
    no previously-included directories found matching 'contrib'
    no previously-included directories found matching 'tasks'
    no previously-included directories found matching 'tests'
Installing collected packages: pip
  Found existing installation: pip 1.4.1
    Uninstalling pip:
Cleaning up...
Exception:
Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/pip-1.4.1-py2.7.egg/pip/basecommand.py", line 134, in main
    status = self.run(options, args)
  File "/Library/Python/2.7/site-packages/pip-1.4.1-py2.7.egg/pip/commands/install.py", line 241, in run
    requirement_set.install(install_options, global_options, root=options.root_path)
  File "/Library/Python/2.7/site-packages/pip-1.4.1-py2.7.egg/pip/req.py", line 1294, in install
    requirement.uninstall(auto_confirm=True)
  File "/Library/Python/2.7/site-packages/pip-1.4.1-py2.7.egg/pip/req.py", line 525, in uninstall
    paths_to_remove.remove(auto_confirm)
  File "/Library/Python/2.7/site-packages/pip-1.4.1-py2.7.egg/pip/req.py", line 1639, in remove
    renames(path, new_path)
  File "/Library/Python/2.7/site-packages/pip-1.4.1-py2.7.egg/pip/util.py", line 294, in renames
    shutil.move(old, new)
  File "/usr/local/Cellar/python/2.7.9/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 300, in move
    rmtree(src)
  File "/usr/local/Cellar/python/2.7.9/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 247, in rmtree
    rmtree(fullname, ignore_errors, onerror)
  File "/usr/local/Cellar/python/2.7.9/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 252, in rmtree
    onerror(os.remove, fullname, sys.exc_info())
  File "/usr/local/Cellar/python/2.7.9/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 250, in rmtree
    os.remove(fullname)
OSError: [Errno 13] Permission denied: '/Library/Python/2.7/site-packages/pip-1.4.1-py2.7.egg/EGG-INFO/dependency_links.txt'

Storing complete log in /Users/[me]/.pip/pip.log

但是，pip 可以正确安装到/usr/local/lib/python2.7/site-packages（Homebrew 提供的版本），我在使用 pip 安装模块和使用模块方面没有明显问题。以下是which 的输出，毕竟上述内容：

$ which pip
/usr/local/bin/pip
$ which python
/usr/local/bin/python

发生了什么事？任何帮助将不胜感激。

Answer 1

我认为这与此处描述的问题相同：https://github.com/pypa/pip/issues/2319

这是由于 sys.path 中有另一个 pip egg 时 pip 行为不端引起的。

最简单的解决方法是继续运行 sudo python -m pip uninstall pip 直到它停止工作，然后运行 ​​brew postinstall python（重新安装 pip）。

Answer 2

我也遇到过这个问题（Yosemite 上的 Homebrew Python 2.7.9）。我试图做pip install virtualenv：

> which pip2.7
/usr/local/bin/pip2.7
> which python
/usr/local/bin/python
> pip install virtualenv
Requirement already satisfied (use --upgrade to upgrade): virtualenv in /Library/Python/2.7/site-packages
> pip install --upgrade virtualenv
..
OSError: [Errno 13] Permission denied: '/Library/Python/2.7/site-packages/virtualenv-1.11.5-py2.7.egg-info/dependency_links.txt'

我通过暂时隐藏/Library/Python/2.7/site-packages 中的文件解决了这个问题。完成后将它们移回。

> pip install virtualenv
Collecting virtualenv
  Using cached virtualenv-12.0.7-py2.py3-none-any.whl
Installing collected packages: virtualenv

Successfully installed virtualenv-12.0.7
> which virtualenv
/usr/local/bin/virtualenv
>

它也可以正常工作。我在 virtualenv 中获得了 2.7.9，可以安装 numpy、matplotlib、scipy，它们可以工作。