Dependency Injection in Godot 4.3+

Patterns for wiring dependencies between systems so nodes stay loosely coupled, swappable, and testable. All examples target Godot 4.3+ with no deprecated APIs.

Related skills: godot-testing for test-friendly architecture, event-bus for signal-based decoupling, godot-project-setup for autoload registration.

1. The Problem

Tight coupling makes code hard to test, extend, and swap. The most common form in Godot is reaching directly into a global autoload from everywhere in the codebase.

# BAD — tight coupling via direct autoload access scattered everywhere