flake8-exact-pin

Check for exact pins (==) of package requirements in install_requires in setup.py.

For example:

setup(
    # ...
    install_requires=['pyramid==1.5.6'],
    # ...
)

Exact pins are often a bad idea, as they:

• Limit flexibility if your package is going to be reused; i.e.: used as a library by other Python libraries or applications. You are forcing them to use a particular version that they may not want to use or that conflicts with what they already use. Not so much of an issue if your package is an application rather than a library; however, often requirements.txt is a better place to manage application requirements that you are pinning (see https://caremad.io/blog/setup-vs-requirement/)
• Bake a very strict requirement into your package; you may have to rebuild your package just to use a new version of a package with a bug fix.
• Create the potential for hard-to-resolve version conflicts, if you exact pin some package versions and don't exact pin others. Some of your other packages may require a different version than the one you're pinning and it might be impossible for pip to resolve this.

Installation

If you don't already have it, install flake8:

$ pip install flake8

Then, install the extension:

$ pip install flake8-exact-pins

Usage

Run the following to verify that the plugin has been installed correctly:

$ flake8 --version
2.4.1 (pep8: 1.5.7, flake8-exact-pin: 0.0.0, pyflakes: 0.8.1, mccabe: 0.3) CPython 2.7.9 on Darwin

Now, when you run flake8, the plugin will automatically be used.

When an exact pin is found, flake8 will output something like:

./setup.py:28:37: PIN001 exact pin found in install_requires: "pyramid==1.5.6"