Automate code standards validation with Composer, Git Hooks and PHPCodeSniffer

| clean code composer git phpcs

Recently I had to setup a new project and like always I prefer to enforce the code standards on the project so that I don’t need to worry about this ever again. Because I realized there are a lot of people who don’t know how this could be accomplished I decided to write a short post about this, maybe it helps others out there. We will use composer, pre-commit git hook and off course phpcs to automate code quality checks.

Install PHPCodeSniffer as a project dependency

First thing we have to do is to add phpcs as a development dependency.

    "require-dev": [
        "squizlabs/php_codesniffer": "^3.2"

Automatically setup git hooks

Because we want to verify the project code standards before any commit, we have to setup a pre-commit git hook. In order to automate this step we can make use of composer scripts which will execute any script or command-line command that we specify at composer install or composer update.

    "scripts": {
        "install-hooks": ["rm -rf .git/hooks", "ln -s ../scripts/hooks .git/hooks", "chmod +x .git/hooks/pre-commit"]
        "pre-install-cmd": ["@install-hooks"],
        "post-install-cmd": ["@install-hooks"],

Composer will copy our pre-commit script from the scripts directory into the hooks of the .git directory and make it executable. In any git project, you have this .git directory that contains the hooks folder where all the git hooks script samples can be found. For more info, visit git hooks documentation.

➜  hooks git:(master) ll
total 80
-rwxr-xr-x  1 iulian.popa  staff   478B Jul  8  2017 applypatch-msg.sample
-rwxr-xr-x  1 iulian.popa  staff   896B Jul  8  2017 commit-msg.sample
-rwxr-xr-x  1 iulian.popa  staff   189B Jul  8  2017 post-update.sample
-rwxr-xr-x  1 iulian.popa  staff   424B Jul  8  2017 pre-applypatch.sample
-rwxr-xr-x  1 iulian.popa  staff   1.6K Jul  8  2017 pre-commit.sample
-rwxr-xr-x  1 iulian.popa  staff   1.3K Jul  8  2017 pre-push.sample
-rwxr-xr-x  1 iulian.popa  staff   4.8K Jul  8  2017 pre-rebase.sample
-rwxr-xr-x  1 iulian.popa  staff   544B Jul  8  2017 pre-receive.sample
-rwxr-xr-x  1 iulian.popa  staff   1.2K Jul  8  2017 prepare-commit-msg.sample
-rwxr-xr-x  1 iulian.popa  staff   3.5K Jul  8  2017 update.sample

The pre-commit hook

Now whenever a developer attempts to commit their code, it will trigger the pre-commit hook. The script will run the phpcs rules on the specific files of the commit:


PROJECT=`php -r "echo dirname(dirname(dirname(realpath('$0'))));"`
STAGED_FILES_CMD=`git diff --cached --name-only --diff-filter=ACMR HEAD | grep \\\\.php`

# Determine if a file list is passed
if [ "$#" -eq 1 ]

echo "Checking PHP Lint..."
    php -l -d display_errors=0 $PROJECT/$FILE
    if [ $? != 0 ]
        echo "Fix the error before commit."
        exit 1

if [ "$FILES" != "" ]
    echo "Running Code Sniffer. Code standard PSR2."
    ./vendor/bin/phpcs --standard=PSR2 --encoding=utf-8 -n -p $FILES
    if [ $? != 0 ]
        echo "Please fix the following errors before commit!"
        exit 1

exit $?

More specific the script will get the staged files before commit, cheking the PHP syntax with php lint (php -l) and apply the phpcs rules, in our case PSR2, on those files. The commit will be aborted if there is a code standards violation.

This is a very simple setup every project should have, it will help you keep the code standards consistent and achieve a cleaner codebase. Hope you’ll like it.

If you liked this post, you can share it on Twitter. Also you can follow me on Github or endorse me on LinkedIn.