🚧 Common Pitfalls for OOP Developers

📘 Table of Contents

When transitioning from Java or other OOP languages to Go, it’s easy to bring habits that don’t fit the Go philosophy.

Here are some common mistakes and how to avoid them:

1. 🧱 Trying to Build Class Hierarchies

  • ❌ Don’t: Attempt to mimic inheritance with complex struct embedding or design deep hierarchies.

  • ✅ Do: Use composition — embed structs for reuse and define small, focused interfaces for polymorphism.

2. 🧩 Overusing Interfaces

  • ❌ Don’t: Create interfaces for every struct “just in case.”

  • ✅ Do: Define interfaces where they are used, not where they are implemented. Go prefers interface consumers, not producers.

3. 🌀 Expecting Constructors and Setters

  • ❌ Don’t: Try to enforce encapsulation through private fields and setter/getter methods.

  • ✅ Do: Use simple factory functions (NewType()) and exported fields when appropriate. Keep things explicit and straightforward.

4. 🪄 Looking for Framework Magic

  • ❌ Don’t: Expect dependency injection frameworks, annotations, or runtime reflection magic.

  • ✅ Do: Embrace explicit wiring and simple initialization. Go favors clarity over automation.

5. 📦 Organizing by Layer Instead of Domain

  • ❌ Don’t: Create separate services/, controllers/, repositories/ folders like in typical OOP MVC projects.

  • ✅ Do: Organize by feature or domain (e.g., internal/logs/) — this makes code easier to navigate and maintain.

6. 🧠 Misusing Pointers

  • ❌ Don’t: Use pointers everywhere by default.

  • ✅ Do: Use pointers only when you need to modify a value, avoid copying large structs, or represent nil. Primitive types and small structs often work best as values.

7. 🔄 Forgetting Error Handling Philosophy

  • ❌ Don’t: Expect try/catch or unchecked exceptions.

  • ✅ Do: Handle errors explicitly with if err != nil and wrap them when needed. This leads to more predictable, robust programs.

8. 🧪 Mocking with Interfaces Too Early

  • ❌ Don’t: Abstract everything into interfaces just for tests.

  • ✅ Do: Introduce interfaces only when you have multiple implementations or need mocking in tests.

9. 🧭 Expecting Runtime Type Safety

  • ❌ Don’t: Depend on reflection or runtime type information to enforce behavior.

  • ✅ Do: Leverage Go’s static typing and compiler checks; simplicity wins over metaprogramming.

10. 🚀 Ignoring Concurrency Primitives

  • ❌ Don’t: Rely solely on threads or locks as in OOP.

  • ✅ Do: Learn and use Go’s goroutines and channels — they’re lightweight and designed for safe, concurrent operations.