create_own_rule.md

3 Steps to Create Your Own Rector

First, make sure it's not covered by any existing Rectors.

Let's say we want to change method calls from set* to change*.

 $user = new User();
-$user->setPassword('123456');
+$user->changePassword('123456');

1. Create a New Rector and Implement Methods

Create a class that extends Rector\Core\Rector\AbstractRector. It will inherit useful methods e.g. to check node type and name. See the source (or type $this-> in an IDE) for a list of available methods.

<?php

declare(strict_types=1);

namespace Utils\Rector;

use Nette\Utils\Strings;
use PhpParser\Node;
use PhpParser\Node\Identifier;
use PhpParser\Node\Expr\MethodCall;
use Rector\Core\Rector\AbstractRector;
use Rector\Core\RectorDefinition\CodeSample;
use Rector\Core\RectorDefinition\RectorDefinition;

final class MyFirstRector extends AbstractRector
{
    /**
     * @return string[]
     */
    public function getNodeTypes(): array
    {
        // what node types are we looking for?
        // pick any node from https://github.com/rectorphp/rector/blob/master/docs/nodes_overview.md
        return [MethodCall::class];
    }

    /**
     * @param MethodCall $node - we can add "MethodCall" type here, because
     *                         only this node is in "getNodeTypes()"
     */
    public function refactor(Node $node): ?Node
    {
        // we only care about "set*" method names
        if (! $this->isName($node->name, 'set*')) {
            // return null to skip it
            return null;
        }

        $methodCallName = $this->getName($node);
        $newMethodCallName = Strings::replace($methodCallName, '#^set#', 'change');

        $node->name = new Identifier($newMethodCallName);

        // return $node if you modified it
        return $node;
    }

    /**
     * From this method documentation is generated.
     */
    public function getDefinition(): RectorDefinition
    {
        return new RectorDefinition(
            'Change method calls from set* to change*.', [
                new CodeSample(
                    // code before
                    '$user->setPassword("123456");',
                    // code after
                    '$user->changePassword("123456");'
                ),
            ]
        );
    }
}

This is how the file structure should look like:

/src/YourCode.php
/utils/Rector/MyFirstRector.php
rector.yaml
composer.json

We also need to load Rector rules in composer.json:

{
    "autoload": {
        "psr-4": {
            "App\\": "src"
        }
    },
    "autoload-dev": {
        "psr-4": {
            "Utils\\": "utils"
        }
    }
}

After adding this to composer.json, be sure to reload Composer's class map:

composer dump-autoload

2. Register It

# rector.yaml
services:
    Utils\Rector\MyFirstRector: ~

3. Let Rector Refactor Your Code

The rector.yaml configuration is loaded by default, so we can skip it.

# see the diff first
vendor/bin/rector process src --dry-run

# if it's ok, apply
vendor/bin/rector process src

That's it!

Generating a Rector Rule

Do you want to save time with making rules and tests?

Use the create-rector command.