Saves the diff between index and working copy

apply-patch.sh

# NOTE(hartikainen): Might want to check that the working tree is clean.
commit_sha="$(cat ./name_rev.txt | awk -F' ' '{print $1}')"
git checkout "${commit_sha}"

echo "Applying patch: $(cat ./patch.diff)"
git apply patch.diff

save_git_diff.py

import os

import git


repository_path = os.getcwd()
repository = git.Repo(repository_path, search_parent_directories=True)

# See https://gitpython.readthedocs.io/en/stable/tutorial.html#obtaining-diff-information
diff = repository.git.diff('HEAD')

with open('./patch.diff', 'w') as f:
    # NOTE(hartikainen): Needs a line break at the end in order for
    # `git apply ...` to work.
    f.write(f"{diff}\n")