Lint PHP version breaking changes with phpcs

Upgrading the php version on your server doesn’t come without risks. With all coding languages, old features can become deprecated or even removed. Trawling through a codebase manually to check it’s still all going to work doesn’t sound fun. So this article shows how to lint php version breaking changes.

Prerequisites

You’ll need PHP’s equivalent of a dependency manager to install the tools you need. In our case, it’s called composer. So make sure you have installed globally and it’s available on your machine before proceeding. You can grab it from here.

You’ll also need to be familiar with some simple terminal/command prompt commands, and this article is aimed at Windows users.

Setup and installation

Due to the way these tools work, I’ve found it best to install them outside of your project folder. So in your command prompt you should cd to the parent directory of your project. For example:

C:\parentdir\yourprojectdir

Once in the parent directory, install the following dependencies:

composer require --dev squizlabs/php_codesniffer
composer require --dev phpcompatibility/php-compatibility

The first dependency is the php codesniffer (phpcs), and the latter will help you determine if there are any compatibility issues with your chosen php version.

You should now have the following directory structure. The vendor folder is where your dependencies live, similar to node_modules for npm. With that, the json and lock files become self explanatory:

/vendor
/yourprojectdir
composer.json
composer.lock

Next, you’ll need to ensure the config has been set correctly for php-compatibility. Run this command in your terminal:

vendor\bin\phpcs --config-set installed_paths vendor/phpcompatibility/php-compatibility

Double check this has been set properly by running the following command:

vendor\bin\phpcs --config-show

Running the phpcs linter

I like to create a bat file for running these kinds of commands, so create a bat file in your parentdir to run your linting e.g phpcheck.bat

In this file you want to add the following code:

@echo off
vendor\bin\phpcs --extensions=php -n --standard=PHPCompatibility --report-file=php8check.txt --runtime-set testVersion 8.0 yourprojectdir

running this bat file in the terminal will create a text file containing any issues with the test. Just replace the php8check.txt, yourprojectdir and 8.0 values with your own values.

Troubleshooting

You might run into this error when running the linter:

ERROR: the "PHPCompatibility" coding standard is not installed. The installed coding standards are MySource, PEAR, PSR1, PSR2, PSR12, Squiz and Zend

Just ensure that phpcompatibility is installed in the parent directory of your project. Sometimes it can be finnicky in detecting the available dependencies, which is why we make sure the config has been set in an earlier step. This is how you lint php version breaking changes.

Want more tips on testing for bugs? Check out how to test for bugs and other issues in a team environment