FawltyDeps is a dependency checker for Python that finds undeclared and/or unused 3rd-party dependencies in your Python project. The name is inspired by the Monty Python-adjacent Fawlty Towers sitcom.

📝 Full documentation available at: tweag.github.io/FawltyDeps

We invite you to join our Discord channel! It's a great place to ask questions, share your ideas, and collaborate with other contributors.

• undeclared dependency: a package that's used (in particular, imported) by a project and which lacks a corresponding declaration to ensure that it's available. For example, you import numpy, but you've forgotten to include numpy in your requirements.txt. Pragmatically, this means the project is prone to runtime errors.
• unused dependency: a package that's declared as necessary for a project but which is never used by project code. For example, you have numpy listed in your requirements.txt, but you never actually import numpy. Pragmatically, this means that project installation may consume more space than needed and will be more likely to break with future software releases; in short, these are costs paid for no benefit.

Your project dependencies may look like this:

But FawltyDeps is all about helping you get to this perfect green spot:

The library is distributed with PyPI, so simply:

pip install fawltydeps

or any other way to install Python packages from PyPI should be enough to make it available in your environment.

Consider adding fawltydeps to your development dependencies, to help you catch undeclared and unused dependencies in your projects.

To check the project in the current directory run:

fawltydeps

This will find imports in all the Python code under the current directory, extract dependencies declared by your project, and then report undeclared and unused dependencies.

For details on setting up your development environment, please refer to the contributing guidelines of how to set up your development environment in our CONTRIBUTING.md file.