siyuan-note/siyuan · error

topic required

Error message

topic required

What it means

Thrown by siyuan.event.emit when the topic argument is an empty string. emit treats '' as no topic and refuses to publish, since bus subscribers key on the topic string.

Source

Thrown at kernel/plugin/api_event.go:50

		}
	}()

	event := rt.NewObject()

	lo.Must0(event.Set("handler", goja.Null()))

	lo.Must0(event.Set("emit", rt.ToValue(func(call goja.FunctionCall, rt *goja.Runtime) goja.Value {
		promise, resolve, reject := rt.NewPromise()

		var argErr error
		var topic string
		var eventData any
		if len(call.Arguments) < 2 {
			argErr = fmt.Errorf("topic and event required")
		} else {
			topic = call.Argument(0).String()
			if topic == "" {
				argErr = fmt.Errorf("topic required")
			} else {
				eventData = call.Argument(1).Export()
			}
		}

		runErr := p.worker.Run(func(rt *goja.Runtime) (result any, err error) {
			if argErr != nil {
				err = argErr
				return
			}
			p.bus.Publish(topic, eventData)
			return
		}, func(rt *goja.Runtime, result any, err error) {
			if lo.IsNil(err) {
				if resolveErr := resolve(result); resolveErr != nil {
					logging.LogErrorf("[plugin:%s] siyuan.event.emit resolve: %v", p.Name, resolveErr)
				}
			} else {

View on GitHub (pinned to 251596fc0d)

Solutions

1. Provide a non-empty topic string.
2. Default the topic: const t = topic || 'default-topic'.

Example fix

// before
siyuan.event.emit('', data);
// after
siyuan.event.emit('my-event', data);

const t = (typeof topic === 'string' && topic.length) ? topic : 'default';
siyuan.event.emit(t, data);

const isTopic = (v) => typeof v === 'string' && v.length > 0;

When it happens

Trigger: Calling emit('', data), or emit(someVar, data) where someVar evaluated to ''.

Common situations: Topic built from optional config that was unset, or a typo/trim leaving an empty string.

Related errors

• topic and event required
• Failed to update agent session permission
• Agent capability name and description are required
• invalid frontend capability ID: %s
• frontend capability description is required: %s

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/7538f9f961daf412. Report an issue: GitHub.