kovidgoyal/kitty · error

could not connect to session D-Bus: %s

Error message

could not connect to session D-Bus: %s

What it means

Portal.Start fails when dbus.SessionBus() cannot connect to the user's session bus (DBUS_SESSION_BUS_ADDRESS). The message wraps the underlying connection error.

Source

Thrown at kittens/desktop_ui/portal.go:185

		Properties: properties,
		Signals:    signals,
	}
	interfaces := []introspect.Interface{
		introspect.IntrospectData, interface_data,
	}
	if len(properties) > 0 {
		interfaces = append(interfaces, prop.IntrospectData)
	}
	n := &introspect.Node{Name: object_path, Interfaces: interfaces}
	if err = conn.Export(introspect.NewIntrospectable(n), op, introspect.IntrospectData.Name); err != nil {
		return fmt.Errorf("failed to export introspected methods with error: %w", err)
	}
	return
}

func (self *Portal) Start() (err error) {
	if self.bus, err = dbus.SessionBus(); err != nil {
		return fmt.Errorf("could not connect to session D-Bus: %s", err)
	}
	reply, err := self.bus.RequestName(PORTAL_BUS_NAME, dbus.NameFlagDoNotQueue)
	if err != nil {
		return fmt.Errorf("failed to register dbus name: %v", err)
	}
	if reply != dbus.RequestNameReplyPrimaryOwner {
		return fmt.Errorf("can't register D-Bus name: name already taken")
	}
	props := PropSpec{
		"version": {Value: uint32(1), Writable: false, Emit: prop.EmitFalse},
	}
	signals := SignalSpec{
		"SettingChanged": {{"namespace", "s"}, {"key", "s"}, {"value", "v"}},
	}
	methods := MethodSpec{
		"Read":    {{"namespace", "s", false}, {"key", "s", false}, {"value", "v", true}},
		"ReadAll": {{"namespaces", "as", false}, {"value", "a{sa{sv}}", true}},
	}

View on GitHub (pinned to 6d5d0c4406)

Solutions

1. Verify DBUS_SESSION_BUS_ADDRESS is set (echo $DBUS_SESSION_BUS_ADDRESS) and points to a live socket
2. Launch a session bus (dbus-launch, eval $(dbus-launch)) or use dbus-run-session
3. In containers/SSH, forward or share the host session bus socket
4. Use dbus-monitor or busctl --user to confirm the bus responds

if os.Getenv("DBUS_SESSION_BUS_ADDRESS") == "" {
    return errors.New("no session bus; set DBUS_SESSION_BUS_ADDRESS")
}

if _, err := dbus.SessionBus(); err != nil {
    // degrade gracefully: disable desktop-ui features
}

When it happens

Trigger: Running the desktop-ui kitten server in an environment without a session bus: SSH sessions without bus address forwarding, containers, cron jobs, or minimal Wayland/X setups.

Common situations: Missing or invalid DBUS_SESSION_BUS_ADDRESS env var; running inside a container or non-graphical session; ssh -X without dbus forwarding.

Related errors

• failed to connect to system bus with error: %w
• failed to register dbus name: %v
• failed to export interface: %s at object path: %s with error
• failed to export properties with error: %w
• failed to export introspected methods with error: %w

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/2b7a6f38787e8ea7. Report an issue: GitHub.