I’m going to write a bit today about PHP_CodeSniffer, which is a tool for detecting PHP style violations.
Background
Convention is good. It’s like following the principle of least surprise in software design, but for your developer audience.
PHP has two code standards that I see in the wild:
If you are writing new PHP code, or refactoring code that follows no discernible standard, you should use the PSR-2 code style.
I use PHP_CodeSniffer on a few projects to stop the build early if the code is not up to standard. It has the ability to fix the formatting problems it finds, so it is not a difficult test to clear.
Add PHP_CodeSniffer to your project
I’m assuming that you are already using composer to manage your PHP dependencies.
Ensure you are specifying your minimum PHP version in your composer.json:
"require": {
"php": ">=7.0.0"
}
Next, add squizlabs/php_codesniffer as a development dependency of your project:
composer require --dev squizlabs/php_codesniffer
Check your code
I use this command to check the src folder. It can be run locally or on a CI box:
php vendor/bin/phpcs --standard=psr2 src/ -n
This will return nonzero if there are problems with the code style, which should stop the build on most systems.
The -n flag avoids less severe “warnings”. One of these is the “Line exceeds 120 characters”, which can be difficult to completely eliminate.
Fixing the style
Running the phpcbf command with the same arguments will correct simple formatting issues:
php vendor/bin/phpcs --standard=psr2 src/ -n
Travis CI example
A full .travis.yml which uses this would look like this (adapted from here):
language: php
php:
- 7.0
- 7.1
- 7.2
install:
- composer install
script:
- php vendor/bin/phpcs --standard=psr2 test/ -n
If you are running a PHP project without any sort of build, then this is a good place to start: Aside from style, this checks that dependencies can be installed on a supported range of PHP versions, and will also break if there are files with syntax errors.