How to find overridden files using preference in Magento 2

developer

March 3, 2025

Magento

Magento 2 provides a robust way to customize its core functionalities without modifying the core files. One of the most common methods used for customization is Preferences (also known as Virtual Types). However, when working on a Magento 2 project, you might need to find which core files have been overridden using preferences.

In this blog, we will discuss how to find overridden files using preferences in Magento 2 and the best practices for handling them.

What is Preference in Magento 2?

Preference in Magento 2 is a dependency injection mechanism that allows developers to override core classes with custom classes. This is achieved by defining a new class in a module and specifying it in the di.xml file.

Example of a preference:

  <preference for="Magento\Catalog\Model\Product" type="Vendor\Module\Model\Product"/>

In the above example, Vendor\Module\Model\Product overrides Magento\Catalog\Model\Product.

How to Find Overridden Files Using Preferences

If you suspect that a core class has been overridden but are unsure where it is happening, follow these methods:

1. Check the di.xml File

Preferences are defined in the di.xml file of modules. To find overridden classes:

Navigate to your Magento installation directory.
Run the following command to search for preference tags:

     grep -r "<preference" app/code/ vendor/

This command will list all occurrences of preferences in the app/code/ (custom modules) and vendor/ (third-party modules and Magento core).

2. Use Command to find file

To display the block on a page, define it inside a layout XML file. Create default.xml inside Vendor/Module/view/frontend/layout/:

  php bin/magento dev:di:info "Magestore\Webpos\Helper"

Below Image Shows the Preference for Magento\Sales\Model\Order\Email\Sender\ShipmentSender which is overwritten by Mageride\ClickandCollect\Model\Order\Email\Sender\ShipmentSender

Best Practices When Using Preferences

Use Plugins Instead: Preferences override entire classes, which can create conflicts with other modules. Consider using Plugins (Interceptors) when modifying behavior instead of overriding complete classes.
Limit Use of Preferences: Only use preferences when absolutely necessary, as they reduce the flexibility of Magento’s modular architecture.
Check for Conflicts: Always verify if multiple modules override the same class, as this can cause unexpected behavior.
Follow Magento Coding Standards: Keep your custom modules and preferences well-documented and compliant with Magento’s best practices.

Conclusion

Finding overridden files using preferences in Magento 2 is essential when debugging customizations or conflicts. By searching the di.xml files, using Magento CLI, inspecting generated code, and applying debugging techniques, you can easily identify and manage overridden classes. However, always consider using Plugins instead of Preferences for better maintainability.

By following these best practices, you can ensure a smooth and conflict-free Magento 2 development experience.

Need Help with Magento Development?

If you’re facing issues with Magento 2 customizations or need expert assistance, feel free to reach out! Our team of Magento specialists is here to help.

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