Check Drupal coding standard by phpcs in git pre-commit hook

Follow the next steps to set up the pre-commit git hook with Drupal coding standards:

1. Create hooks directory on root project.
2. Create a pre-commit file in the hooks directory.
3. Add the below pre-commit code to the hooks/pre-commit file.

#!/bin/bash

STANDARD="Drupal"
BIN="./vendor/bin"

echo
echo "Drupal Coder pre-commit hook – commit with the --no-verify option to skip the hook"
echo

# Check whether PHP_CodeSniffer can be found
if [ ! -f "$BIN/phpcs" ]
then
  echo "Drupal Coder not found – is it installed? 'composer require drupal/coder'"
  echo
  exit 1
fi

# Retrieve staged files
FILES=$(git diff --cached --name-only --diff-filter=ACMR HEAD)

# Run the sniffer
echo "Running Drupal Coder."
echo
PHPCS=("$BIN/phpcs" "--standard=$STANDARD" "--filter=gitstaged" "--encoding=utf-8" "-p" ".")
"${PHPCS[@]}"

# Syntax Error
if [ $? != 0 ]
then
  echo "Please fix each violations detected."
  echo
  exit 1
fi

# Syntax OK
if [ $? == 0 ]
then
  echo "No violations detected"
  echo
  exit 0
fi

Add PHP commands on the scripts section of the composer.json file.

"scripts": {
      "post-install-cmd": [
          "php -r \"copy('hooks/pre-commit', '.git/hooks/pre-commit');\"",
          "php -r \"chmod('.git/hooks/pre-commit', 0755);\""
      ]
}

How to use it

git commit -m "The commit message."

This is going to execute Drupal Coder on each file and returns messages on the terminal in case of finding errors on files.