为什么Pip忽略了相互冲突的依赖？

Question

如果我创建一个虚拟包--这里是/tmp/样例_ package /setup.py(注意需求)：

from distutils.core import setup

setup(name='my_project',
      description="Just a test project",
      version="1.0",
      py_modules=['sample'],
      install_requires=['requests > 0.12'])

下面是/tmp/样例_package/sample.py：

import requests

def get_example():
    return requests.get("http://www.example.com")

现在，我创建了一个虚拟环境：

$ virtualenv /tmp/foobar --distribute -p python2.7
Running virtualenv with interpreter /usr/bin/python2.7
New python executable in /tmp/foobar/bin/python2.7
Also creating executable in /tmp/foobar/bin/python
Installing distribute.................................................................................................................................................................................................done.
Installing pip................done.
$ source /tmp/foobar/bin/activate

我创建了一个具有冲突需求的requirements.pip 。

# this requires requests > 0.12:
file:///tmp/example_package

# but this conflicts:
requests==0.9.0

Pip愉快地安装如下：

$ pip install -r requirements.pip                                                                                                                                                                       [18:40:10]
Unpacking ./example_package
  Running setup.py egg_info for package from file:///tmp/example_package

Downloading/unpacking requests==0.9.0 (from -r requirements.pip (line 3))
  Downloading requests-0.9.0.tar.gz (55Kb): 55Kb downloaded
  Running setup.py egg_info for package requests

Downloading/unpacking certifi>=0.0.4 (from requests==0.9.0->-r requirements.pip (line 3))
  Downloading certifi-0.0.8.tar.gz (118Kb): 118Kb downloaded
  Running setup.py egg_info for package certifi

Installing collected packages: requests, my-project, certifi
  Running setup.py install for requests

  Running setup.py install for my-project

  Running setup.py install for certifi

Successfully installed requests my-project certifi
Cleaning up...

为什么皮普允许这样做？我的example_package不能工作，因为它的要求没有得到满足。

Answer 1

这是皮普的一个限制。需求文件高于包的要求。请参阅https://github.com/pypa/pip/issues/775#issuecomment-12748095

Answer 2

从pip源代码来看，它似乎应该递归地将所有需求添加到一个大型RequirementSet中。然后以“重复需求”的异常崩溃.

嗯..。你确定你的setup.py是正确的吗？

Distutils有一个requires关键字，但没有install_requires：http://docs.python.org/2/distutils/setupscript.html#relationships-between-distributions-and-packages

因此，回答中提到了这一点：

https://stackoverflow.com/a/10686196/202168

https://stackoverflow.com/a/13468644/202168