Leak detection

Goal: Find event subscriptions whose handler target (UnityEngine.Object) was destroyed without an unsubscribe.

How it works

When IL instrumentation records a subscribe, Event Monitor tracks handlers whose delegate target is a UnityEngine.Object using a weak reference. On scene unload and periodic scans in Play Mode, destroyed targets are reported as leaks.

Where to see leaks

1. Open Window → Event Monitor.
2. Open the Stats tab.
3. Review the Leaks section. When leaks exist, the tab label shows Stats (N leaks).

Each leak row lists event name, owner type, subscriber type, method, and detection context.

Limitations

• Unity object targets only — static handlers and pure C# object targets are not tracked.
• Requires recording — leak tracking runs when Record is ON.
• Not a substitute for domain reload analysis — best for Play Mode lifecycle bugs (destroy without -=).

Typical fix

Unsubscribe in OnDisable / OnDestroy before the subscriber object is destroyed:

void OnDisable()
{
    owner.OnChanged -= HandleChanged;
}

See also

• Event bus and records
• IL limitations