`nerdctl kill` shouldn't set `containerd.io/restart.explicitly-stopped` label for non-stop signals

[AkihiroSuda]

nerdctl/pkg/cmd/container/kill.go

Lines 82 to 127 in 592c011

	func killContainer(ctx context.Context, container containerd.Container, signal syscall.Signal) (err error) {
	defer func() {
	if err != nil {
	containerutil.UpdateErrorLabel(ctx, container, err)
	}
	}()
	if err := containerutil.UpdateExplicitlyStoppedLabel(ctx, container, true); err != nil {
	return err
	}
	task, err := container.Task(ctx, cio.Load)
	if err != nil {
	return err
	}
	status, err := task.Status(ctx)
	if err != nil {
	return err
	}
	paused := false
	switch status.Status {
	case containerd.Created, containerd.Stopped:
	return fmt.Errorf("cannot kill container %s: container is not running", container.ID())
	case containerd.Paused, containerd.Pausing:
	paused = true
	default:
	}
	if err := task.Kill(ctx, signal); err != nil {
	return err
	}
	// Clean up healthcheck systemd units
	if err := healthcheck.RemoveTransientHealthCheckFiles(ctx, container); err != nil {
	log.G(ctx).Warnf("failed to clean up healthcheck units for container %s: %s", container.ID(), err)
	}
	// signal will be sent once resume is finished
	if paused {
	if err := task.Resume(ctx); err != nil {
	log.G(ctx).Warnf("cannot unpause container %s: %s", container.ID(), err)
	}
	}
	return nil
	}

nerdctl kill can be used for non-stop signals such as HUP, so it shouldn't unconditionally set containerd.io/restart.explicitly-stopped label