Use Rector to automatically upgrade legacy PHP code (abandoned modules) for you

[dotnetic]

Introduction to RectorPHP
In the dynamic world of PHP development, code refactoring is an inevitable task, whether for code optimization or transitioning to newer PHP versions. RectorPHP stands as a vital tool, simplifying this often challenging process. So, what is RectorPHP?

What is RectorPHP?
RectorPHP, or Rector, is a revolutionary open-source tool created to automate the process of refactoring PHP code. Refactoring, in simple terms, refers to the modification of a software system's internal structure without changing its external behavior, ultimately leading to enhanced readability and maintainability.

Built on the powerful PHP Parser library, Rector analyzes and manipulates PHP code at the abstract syntax tree (AST) level. This granular control allows for intricate adjustments, making refactoring a breeze. But Rector's capabilities don't end here. Its true strength lies in its role as an automatic code upgrade tool.

RectorPHP as an Automatic Code Upgrade Tool
RectorPHP's primary role is to transition PHP code from legacy standards to modern, efficient, and more secure versions. This transformation allows developers to maintain their codebase up to date, benefiting from the latest advancements in PHP development.

How Can RectorPHP Upgrade Your PHP Code?
RectorPHP provides a smooth and efficient roadmap to upgrade old PHP code to contemporary versions. Here's how:

Installation
The first step is to install Rector in your project. Given it's a composer-based project, installing is as simple as running

composer require rector/rector --dev

in your terminal.

Configuration
Next, Rector requires a configuration file (rector.php) to instruct it on what to refactor. This file, located at the root of your project, should specify the rule sets Rector should adhere to.

For instance, the following configuration upgrades PHP code to PHP 8.1:

<?php

declare(strict_types=1);

use Rector\CodeQuality\Rector\Class_\InlineConstructorDefaultToPropertyRector;
use Rector\Config\RectorConfig;
use Rector\Set\ValueObject\LevelSetList;

return static function (RectorConfig $rectorConfig): void {
    $rectorConfig->paths([
        __DIR__ . '/src'
    ]);

    // register a single rule
    $rectorConfig->rule(InlineConstructorDefaultToPropertyRector::class);

    // define sets of rules
        $rectorConfig->sets([
            LevelSetList::UP_TO_PHP_80
        ]);
};

Refactoring
With Rector installed and configured, it's time to initiate the refactoring process. Execute vendor/bin/rector process in your terminal, and Rector will begin refactoring your code, illustrating the changes as it progresses.

Review and Test
While Rector often delivers flawless results, it's still a good practice to examine the modifications it makes. Ensuring that the changes conform to your project's requirements and haven't led to any unforeseen behaviors is a smart move. To further ascertain that your system's functionality remains unscathed, it's advisable to run your test suite. Remember, these steps aren't strictly necessary, but they add an extra layer of safety to your refactoring process.

Rector also provides a "dry run" feature, where it displays the proposed changes without actually modifying the codebase. This feature is useful to preview what Rector will do before allowing it to alter your project.

Conclusion
RectorPHP is an essential tool for PHP developers looking to modernize their codebase efficiently. By simplifying the refactoring process and offering a seamless upgrade path for transitioning to more recent PHP versions, Rector empowers developers to focus on crafting high-quality software. Utilizing Rector means keeping your PHP code in sync with the rapidly evolving landscape of PHP development.

[Rudy]

To allow Rector to inspect/refactor older modules, you also need to add the following config to your rector.php

$rectorConfig->fileExtensions(['php', 'module']);