pre-commit

#!/bin/bash

# Copyright 2019 Toyota Research Institute.  All rights reserved.

# Git pre-commit hook to check staged Python files for formatting issues with
# yapf.
#
# When running, this first checks for unstaged changes to staged files, and if
# there are any, it will exit with an error. Files with unstaged changes will be
# printed.
#
# If all staged files have no unstaged changes, it will run yapf against them,
# leaving the formatting changes unstaged. Changed files will be printed.
#
# BUGS: This does not leave staged changes alone when used with the -a flag to
# git commit, due to the fact that git stages ALL unstaged files when that flag
# is used.


# Find all staged Python files, and exit early if there aren't any.
PYTHON_FILES=$(git diff --name-only --cached --diff-filter=AM | \
  grep --color=never '.py$' | grep -Fv '_pb2')
PYTHON_FILES="${PYTHON_FILES//$'\n'/ }" # Replace all newline with a space.
if [ ! "${PYTHON_FILES[@]}" ]; then
  exit 0
fi

# Check for unstaged changes to files in the index.
CHANGED_FILES=$(git diff --name-only "${PYTHON_FILES}")
CHANGED_FILES="${CHANGED_FILES//$'\n'/ }" # Replace all newline with a space.
if [ "${CHANGED_FILES[@]}" ]; then
  echo 'You have unstaged changes to some files in your commit; skipping '
  echo 'autoformat. Please stage, stash, or revert these changes. You may '
  echo "find 'git stash -k' helpful here."
  echo
  echo 'Files with unstaged changes:'
  for file in ${CHANGED_FILES}; do
    echo "  $file"
  done
  exit 1
fi


echo 'Fixing import order in Python files . . .'
isort "${PYTHON_FILES}"

# Format all staged files, then exit with an error code if any have uncommitted
# changes.
echo 'Formatting staged Python files with YAPF . . .'
yapf --style .style.yapf -i -r --exclude '*pb2.py' --exclude '*pb2_grpc.py' --exclude '*eggs*.py' --exclude '*env*' --exclude 'build/*' "${PYTHON_FILES}"

CHANGED_FILES=$(git diff --name-only "${PYTHON_FILES[@]}")
if [ "${CHANGED_FILES[@]}" ]; then
  echo 'Reformatted staged files. Please review and stage the changes.'
  echo
  echo 'Files updated:'
  for file in "${CHANGED_FILES[@]}"; do
    echo "  $file"
  done
  exit 1
else
  exit 0
fi