setup-php VS PHP Code Sniffer

I found shivammathur/setup-php did a better job on supporting old PHP versions, and you don't have to worry about the composer & extension compatibility, it handles those for you.

this is a good base https://github.com/shivammathur/setup-php

Setup PHP (GitHub Action)

There is also an RSS feed you can subscribe for setup-php releases https://github.com/shivammathur/setup-php/releases.atom

PHP Insights supports sniffs from PHP CodeSniffer and fixers from PHP CS Fixer. This allows you to add any sniff or fixer as long as it implements PHP_CodeSniffer\Sniffs\Sniff or PhpCsFixer\Fixer\FixerInterface.

I don’t know why but that link keeps reloading the page over and over. This one works for me: https://github.com/squizlabs/PHP_CodeSniffer/issues/3932

PHP_CodeSniffer is a widely-used tool for enforcing coding standards in PHP. It checks the code against a set of predefined coding standards (such as PSR-12, PSR-2, and many others) and provides reports with violations and recommendations for improvement. Documentation: You can find more information about PHP_CodeSniffer and its usage in the official documentation: PHP_CodeSniffer Repository

While you're at it, also include code-style checkers like phpcs, phpmd and/or php-cs-fixer

See https://github.com/squizlabs/PHP_CodeSniffer

If you are well-versed in programming then you might wanna take a look at PHPCompatibility. It will scan your codebase at different PHP version rulesets to point out code that needs upgrading. You will be needing PHPCS for this.

PHP code sniffer