What are bad sides of using Symfony's ServiceLocator?

Question

The college told me that sometimes I overuse ServiceLocator in Symfony 5.4 project. I never considered that possibility. Everything seems straightforward => you get services from the container as you usually do. Instead of using a factory, you use a service locator and you do not care about dependencies.

So, am I right here, or it is possible to overuse ServiceLocator in Symfony? If yes please advice when it is ok to use it?

Answer 1

You should use inversion of control through dependency injection. Main advantages of this approach (in no specific order and maybe I'm forgetting some of them)

• you're not tied to the whole container
• you have a clear overview of all dependency
• you can write code over interfaces instead of concrete implementations
• your classes become more testable

So if you're using service locator everywhere for your dependencies, I agree that you're overusing it