Dependency Injection Without Pain: Symfony, Laravel, and Drupal Explained

Introduction

Dependency Injection (DI) is a cornerstone of modern PHP frameworks, but many developers—especially those coming from Drupal—find it confusing. Why inject services instead of calling them directly? How do DI containers differ between Drupal, Symfony, and Laravel?

In this article, we’ll break it down with practical examples, showing how to use DI without headaches across these three systems.

1. What is Dependency Injection?

Simply put: