Common Pitfalls

Common Pitfalls

1. Modules Must Be Fields or Properties

Network modules must be declared as a field or property on a NetworkIdentity. Do not create them dynamically or store them in collections.

public class MyNetworkObject : NetworkIdentity
{
    public SyncVar<int> health; // ✅ Correct
    private SyncList<string> names; // ✅ Correct

    // ❌ Incorrect: Do not use lists of modules
    public List<SyncVar<int>> invalidList; 
}

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2. Editor Serialization

Modules can be serialized and shown in the Unity Editor. Just mark them with [SerializeField] or make them public.

[SerializeField]
private SyncVar<int> health; // Will show up in the Inspector

public SyncList<string> names; // Also visible if public

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3. Initialization: Use OnInitializeModules()

You can create, override, or initialize modules in the protected virtual void OnInitializeModules() callback. This runs before networking sends data or assigns IDs.

protected override void OnInitializeModules()
{
    health = new SyncVar<int>(100);
    // Custom initialization here
}

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4. Do Not Replace Modules After Spawn

Once spawned, never assign a new module instance to a field/property. Doing so will break networking or cause undefined behavior. Modules are meant to be constant after spawn.

// ❌ Don't do this after spawn:
health = new SyncVar<int>(200); // Will break networking!

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5. Nesting Modules

You can nest modules—meaning a network module can use other modules like SyncVar as fields or properties.

public class MyModule : NetworkModule
{
    public SyncVar<int> score; // ✅ Allowed
}

Do not create circular dependencies. If Module A uses Module B, and Module B uses Module A, it will break. Nesting must form a tree, not a loop.

// ❌ Not allowed: Circular reference
public class ModuleA : NetworkModule
{
    public ModuleB b;
}

public class ModuleB : NetworkModule
{
    public ModuleA a; // This creates a cycle and will cause compiler error
}

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6. No Lists of Modules

You cannot create a list or array of modules. Modules must be declared as fields or properties at compile time.

// ❌ Not allowed:
public List<SyncVar<int>> moduleList;

// ✅ Allowed:
public SyncVar<int> health;
public SyncVar<int> mana;

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7. Module Events

Modules have similar events to NetworkIdentity, such as:

• OnSpawned

• OnOwnerChanged

• OnDespawned

You can use these for custom logic inside your modules.

public class MyModule : NetworkModule
{
    protected override void OnSpawned() { /* ... */ }
    protected override void OnOwnerChanged(..) { /* ... */ }
    protected override void OnDespawned() { /* ... */ }
}