What happens when EmitSignal has no listeners?

Nothing. The call succeeds, the engine logs nothing in shipping, and execution continues. Useful when listeners are optional; surprising when you forgot to connect. Add a debug-mode listener-count check to catch silent silences during dev.

Should I use signals or C# events?

Signals: cross-language (Blueprint can listen), inspector-connectable, Engine-managed. C# events: type-safe, faster (no marshaling), can throw if no subscriber via Invoke check. Pick signals for cross-cutting Godot patterns; events for pure-C# pipelines.

How do I detect missing listeners at runtime?

GetSignalConnectionList(signalName).Count gives the current listener count. Wrap critical EmitSignal calls with a debug assert when count is 0 — catches forgotten Connect calls during testing.

Fix: Godot C# Signal Emit Fails Silently with No Listeners

Quick answer: Check listener count with GetSignalConnectionList(signalName).Count in debug builds. Or replace with a typed C# event whose null-check enforces a subscriber.

A boss death signal was supposed to trigger a level-end screen. Boss dies; no screen appears. EmitSignal ran without error. The Connect call lived in a different scene file that wasn’t loaded. Signal fired into the void.

Silent Emit by Design

Godot signals are loosely coupled. EmitSignal broadcasts to any subscriber; zero subscribers is valid. This avoids hard dependencies (a publisher doesn’t need to know if anyone’s listening) but hides “I forgot to wire it up” mistakes.

Debug-Mode Listener Check

public void EmitWithCheck(string signalName, params Variant[] args)
{
    #if DEBUG
    int count = GetSignalConnectionList(signalName).Count;
    if (count == 0) {
        GD.PrintErr($"Signal {signalName} emitted with no listeners");
    }
    #endif
    EmitSignal(signalName, args);
}

In debug builds, prints a warning when emitting with no listeners. Catches missing Connect calls during dev; ships zero-overhead in release.

Type-Safe C# Events

public partial class Boss : Node
{
    [Signal] public delegate void DiedEventHandler();

    public void Die() {
        // Cross-language; loose
        EmitSignal(SignalName.Died);
    }
}

Godot 4 generates an event from the [Signal] delegate. Cross-language compatible but still silent on no listeners. For pure-C# scenarios, define a regular C# event:

public event System.Action OnDied;

public void Die() {
    if (OnDied == null) {
        GD.PrintErr("OnDied has no subscribers!");
    }
    OnDied?.Invoke();
}

Null-check before invoke gives you a place to react to missing subscribers (log, throw, default behavior).

Default Listeners

For systems where listeners are optional but you want a default:

boss.OnDied += () => GD.Print("Boss died (no other listeners)");   // fallback
// Other systems can also subscribe

Ensures the signal is never silent in shipping; debug log says “default fired” rather than nothing.

Verifying

Re-trigger the boss death. In debug, see the log warning if no listeners. After connecting the actual listener, no warning and the level-end screen appears.

“Silent signals are convenient until they hide bugs. Listener-count check or default subscriber turns silence into observable behavior.”

Critical game-flow signals should always have an asserted listener — gameplay milestones aren’t optional emissions.