Git checkstyle pre-commit hook

pre-commit

#!/bin/bash -e
set -x

DIFF=$(git diff master --name-only | grep java | xargs)
JAR_SRC="https://github.com/checkstyle/checkstyle/releases/download/checkstyle-8.32/checkstyle-8.32-all.jar"
JAR_PATH="checkstyle-8.32-all.jar"

if [ -z "$DIFF" ]; then
  exit 0
fi

if [[ ! -f "$JAR_PATH" ]]; then
  echo "Downloading $JAR_SRC";
  curl -L -o "$JAR_PATH" $JAR_SRC;
fi

java -jar "$JAR_PATH" -c /google_checks.xml $DIFF