在我的Buildbot虚拟环境中，我一直面临着安装龙卷风的奇怪错误，龙卷风是sphinx-autobuild==0.6.0的依赖。
>>> pip install --upgrade sphinx-autobuild==0.6.0
Collecting tornado>=3.2 (from sphinx-autobuild==0.6.0->-r towerportal/requirements.txt (line 76))
Using cached https://files.pythonhosted.org/packages/cf/d1/3be271ae5eba9fb59df63c9891fdc7d8044b999e8ac145994cdbfd2ae66a/tornado-5.0.2.tar.gz
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/tmp/pip-build-Bpw6k7/tornado/setup.py", line 192, in <module>
**kwargs
File "/spare/local/buildslave/.pyenv/versions/2.7.12/lib/python2.7/distutils/core.py", line 111, in setup
_setup_distribution = dist = klass(attrs)
File "/spare/local/buildslave/slaveA/demoA/build/virt/lib/python2.7/site-packages/setuptools/dist.py", line 269, in __init__
_Distribution.__init__(self,attrs)
File "/spare/local/buildslave/.pyenv/versions/2.7.12/lib/python2.7/distutils/dist.py", line 287, in __init__
self.finalize_options()
File "/spare/local/buildslave/slaveA/demoA/build/virt/lib/python2.7/site-packages/setuptools/dist.py", line 325, in finalize_options
ep.load()(self, ep.name, value)
File "/spare/local/buildslave/slaveA/demoA/build/virt/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2310, in load
return self.resolve()
File "/spare/local/buildslave/slaveA/demoA/build/virt/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2320, in resolve
raise ImportError(str(exc))
ImportError: 'module' object has no attribute 'check_specifier'
我的setuptools版本是39.0.1。幸运的是，使用pip install -I setuptools重新安装setuptools可以解决问题。但我真正的问题是，重新安装具有相同版本名称的相同软件包真的会发生什么变化才能解决问题？是否setuptools错误地发布了相同版本的不同代码库？