Finding dead code in large python project

Brian Postow picture Brian Postow · Mar 1, 2012 · Viewed 20.9k times · Source

I've seen How can you find unused functions in Python code? but that's really old, and doesn't really answer my question.

I have a large python project with multiple libraries that are shared by multiple entry point scripts. This project has been accreting for many years with many authors, so there's a whole lot of dead code. You know the drill.

I know that finding all dead code is un-decidable. All I need is a tool that will find all functions that are not called anywhere. We're not doing anything fancy with calling functions based on the string of the function name, so I'm not worried about anything pathological...

I just installed pylint, but it appears to be file based, and not paying much attention to interfile dependencies, or even function dependencies.

Clearly, I could grep for def in all of the files, get all of the function names from that, and do a grep for each of those function names. I'm just hoping that there's something a little smarter than that out there already.

ETA: Please note that I don't expect or want something perfect. I know my halting-problem-proof just as well anyone (No really I taught theory of computation I know when I'm looking at something that is recursively enumerable). Any thing that tries to approximate it by actually running the code is going to take way too long. I just want something that syntactically goes through the code and says "This function is definitely used. This function MIGHT be used, and this function is definitely NOT used, no one else even seems to know it exists!" And the first two categories aren't important.

Answer

Keith Gaughan picture Keith Gaughan · Aug 14, 2013

You might want to try out vulture. It can't catch everything due to Python's dynamic nature, but it catches quite a bit without needing a full test suite like coverage.py and others need to work.