pip 10 no module named pip.req

问题:

1. Installation of pip using get-pip.py is breaking. it says

   Requirement already up-to-date: pip in /tmp/tmpvF6RoH/pip.zip (10.0.0)

2. No module named pip.req

while installing a pip module

Traceback (most recent call last):
  File "setup.py", line 5, in <module>
    from pip.req import parse_requirements
ImportError: No module named pip.req

回答1:

Installation

For installation using get-pip.py use the --force-reinstall flag:

$ python get-pip.py --force-reinstall

Obviously this is till they fix the problem https://github.com/pypa/pip/issues/5220

---

Recommended Alternative to pip's internal commands

Avoid putting any dependency links in your requirements.txt file. Instead use the method mentioned below. You can directly put the dependency links in you setup.py file. Some famous packages also maintain the requirements inside the setup.py file in the form of a list and don't have any requirements.txt file

with open('requirements.txt') as f:
    install_requires = f.read().strip().split('\n')

setup(
    name='app_name',
    .
    .
    install_requires=install_requires,
    dependency_links=[
        'https://github.com/frappe/python-pdfkit.git#egg=pdfkit'
    ],
    cmdclass = \
    {
        'clean': CleanCommand
    }
)

---

Imports from pip (BAD PRACTICE - DO NOT USE as it may break anytime! )

It is highly recommended that you avoid this because, as mentioned in the pip user guide, these methods are not thread safe. Also since they're pip's private methods, they may change it anytime without any prior notice, thereby breaking your package installation!

If you have any imports from pip, such as:

from pip.req import parse_requirements

it'll break. Since these have been now moved to pip._internal as such:

from pip._internal.req import parse_requirements

However effectively you'll have to use something like this for backward compatibility:

try: # for pip >= 10
    from pip._internal.req import parse_requirements
except ImportError: # for pip <= 9.0.3
    from pip.req import parse_requirements

---

Important

Now that said it's not a good practice to use the internal pip functions, due to multiple reasons as mentioned here: https://pip.pypa.io/en/latest/user_guide/#using-pip-from-your-program