A useful Git post-checkout hook for Python repos

Every now and again, an innocent python developer checks out a new git branch then proceeds to bang their head against a bug caused by an orphaned .pyc file from the previous branch. Since *.pyc files are typically in the repo’s .gitignore file, they are not removed when switching branches and can cause issues if the corresponding .py is removed.

This can be neatly addressed through a ‘post checkout’ hook which deletes all such files. Here is such a script, which also removes empty folders and prints a summary:

#!/usr/bin/env bash

# Delete .pyc files and empty directories from root of project
cd ./$(git rev-parse --show-cdup)

# Clean-up
find . -name ".DS_Store" -delete

NUM_PYC_FILES=$( find . -name "*.pyc" | wc -l | tr -d ' ' )
if [ $NUM_PYC_FILES -gt 0 ]; then
    find . -name "*.pyc" -delete
    printf "\e[00;31mDeleted $NUM_PYC_FILES .pyc files\e[00m\n"
fi

NUM_EMPTY_DIRS=$( find . -type d -empty | wc -l | tr -d ' ' )
if [ $NUM_EMPTY_DIRS -gt 0 ]; then
    find . -type d -empty -delete
    printf "\e[00;31mDeleted $NUM_EMPTY_DIRS empty directories\e[00m\n"
fi

Sample output:

Inspiration:

Finally automated. Stop being bitten by residual .pyc files when switching branches in git. stackoverflow.com/questions/1504…

— Maik Hoepfel (@maikhoepfel) March 31, 2013

The above version is an extension of the snippets in the referenced Stack Overflow question.