更新python包后出现“InvalidRequirement：无效的要求，解析错误”错误
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"InvalidRequirement: Invalid requirement, parse error" error after updating a python package
提问by ThiefMaster
After updating a package (IPython in my case) using pip install -U ipythonrunning any Python script that uses entry points fails with this error:
使用pip install -U ipython运行任何使用入口点的 Python 脚本更新包（在我的情况下为 IPython）后失败并显示以下错误：
Traceback (most recent call last):
File "/home/adrian/dev/indico/env/bin/indico", line 5, in <module>
from pkg_resources import load_entry_point
...
File "/home/adrian/dev/indico/env/lib/python2.7/site-packages/pkg_resources/_vendor/packaging/requirements.py", line 94, in __init__
requirement_string[e.loc:e.loc + 8], requirement_string))
pkg_resources._vendor.packaging.requirements.InvalidRequirement: Invalid requirement, parse error at "'< 2.0'"
Nothing else changed, I did not update any other libraries.
没有其他变化，我没有更新任何其他库。
采纳答案by ThiefMaster
This is caused by an issue in setuptools==20.2.1which is pulled in by IPython (setuptools>..), so a pip install -Uupdated it.
这是setuptools==20.2.1由 IPython ( setuptools>..)引入的问题引起的，因此对其进行了pip install -U更新。
Until a fixed version is released or the broken version is pulled from PyPI there is a simple workaround (but note that it will break again if something updates setuptools):
在发布固定版本或从 PyPI 中提取损坏的版本之前，有一个简单的解决方法（但请注意，如果更新 setuptools 它将再次损坏）：
pip install -U pippip uninstall setuptoolspip install 'setuptools<20.2'
pip install -U pippip uninstall setuptoolspip install 'setuptools<20.2'
The pipupdate is needed since older versions of pipwill not work without setuptoolsbeing installed
在pip因为旧版本的更新，需要pip将无法正常工作没有setuptools安装
See these IRC logs and BitBucket issue for details:
有关详细信息，请参阅这些 IRC 日志和 BitBucket 问题：
回答by juanpaolo
Try downgrading your pip to 8.1.1:
尝试将您的 pip 降级为8.1.1：
pip install pip==8.1.1
That solved it for me.
那为我解决了。
