What is the best way to override constructor of a class - Magento 2.4.3

Question

I want to make a single line change in the constructor of a core class. What would be the best recommended practice to achieve it.

Here is what my existing constructor

/**
     * Download constructor.
     *
     * @param Context $context
     * @param Filesystem $filesystem
     * @param FileFactory $fileFactory
     */
    public function __construct(
        Context $context,
        Filesystem $filesystem,
        FileFactory $fileFactory
    ) {
        $this->fileFactory = $fileFactory;
        $this->directory = $filesystem->getDirectoryRead(DirectoryList::LOG);

        parent::__construct($context);
    }

and I want to change it like this

/**
     * Download constructor.
     *
     * @param Context $context
     * @param Filesystem $filesystem
     * @param FileFactory $fileFactory
     */
    public function __construct(
        Context $context,
        Filesystem $filesystem,
        FileFactory $fileFactory
    ) {
        $this->fileFactory = $fileFactory;
        $this->directory = $filesystem->getDirectoryRead(DirectoryList::**VAR_DIR**);

        parent::__construct($context);
    }

Should I use preference for this?

Answer 1

Check below code and use as per your requirement.

Create a new class that extends the original class and overrides the constructor.

<?php

namespace Your\Module\Model;

use Magento\Framework\Model\AbstractModel;

class MyModel extends AbstractModel
{
    protected $dependency;

    public function __construct(
        //Inject the original constructors dependency
        \Magento\Framework\Model\Context $context,
        \Magento\Framework\Registry $registry,
        // Add new dependency
        \My\Dependency\Class $dependency,
        array $data = []
    ) {
        parent::__construct($context, $registry, $data);
        // Use the new dependency
        $this->dependency = $dependency;
    }
}

Define a new preference for your class in a di.xml file. This file should be located in app/code/Your/Module/etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Magento\Framework\Model\AbstractModel" type="Your\Module\Model\MyModel" />
</config>

In this example, we have added a new dependency \My\Dependency\Class to the constructor of the original class Magento\Framework\Model\AbstractModel and created a new class Your\Module\Model\MyModel that extends the original class and overrides its constructor.

In the di.xml file, we have defined a preference for the original class and specified that our new class should be used instead.

UPDATED

Here is an example of how to use override the __construct property using plugin:

Setp 1 :- Create etc/di.xml file.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Vendor\Module\Model\YourClass">
        <plugin name="your_plugin_name" type="Vendor\Module\Plugin\YourPlugin" sortOrder="1" />
    </type>
</config>

Step 2 :- Now Create plugin in this path Plugin\YourPlugin.php

<?php
        
namespace Vendor\Module\Plugin;

use Closure;
use Vendor\Module\Model\YourClass;

class YourPlugin
{
    public function __construct(
        // You want to override constructor parameter here
    ) {
        // You want to override constructor parameter here
    }

    public function aroundYouWantFunction(YourClass $subject, Closure $proceed)
    {
        // Do something before the original __construct method is called
        // ...

        // Call the original __construct method
        $proceed();

        // Do something after the original __construct method is called
        // ...
    }
}

  

Let me know if any query.

THANKS.