Add checks for not topology owned templates to never reconcile.

internal/controllers/topology/cluster/current_state.go

@@ -119,6 +119,12 @@ func (r *Reconciler) getCurrentControlPlaneState(ctx context.Context, cluster *c
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to get InfrastructureMachineTemplate for %s", tlog.KObj{Obj: res.Object})
 	}
+	// check that the referenced object has the ClusterTopologyOwnedLabel label.
+	// Nb. This is to make sure that a managed topology cluster does not have a reference to an object that is not
+	// owned by the topology.
+	if !labels.IsTopologyOwned(res.InfrastructureMachineTemplate) {
+		return nil, fmt.Errorf("referenced infra cluster object %s is not topology owned", tlog.KObj{Obj: res.InfrastructureMachineTemplate})
+	}
 
 	mhc := &clusterv1.MachineHealthCheck{}
 	// MachineHealthCheck always has the same name and namespace as the ControlPlane object it belongs to.
@@ -158,6 +164,12 @@ func (r *Reconciler) getCurrentMachineDeploymentState(ctx context.Context, clust
 	for i := range md.Items {
 		m := &md.Items[i]
 
+		// check that the MachineDeployment has the ClusterTopologyOwnedLabel label.
+		// Nb. This is to make sure that a managed topology cluster does not have a reference to an object that is not
+		// owned by the topology.
+		if !labels.IsTopologyOwned(m) {
+			return nil, fmt.Errorf(" %s is not topology owned", tlog.KObj{Obj: m})
+		}
 		// Retrieve the name which is assigned in Cluster's topology
 		// from a well-defined label.
 		mdTopologyName, ok := m.ObjectMeta.Labels[clusterv1.ClusterTopologyMachineDeploymentLabelName]

internal/controllers/topology/cluster/current_state_test.go

@@ -57,6 +57,7 @@ func TestGetCurrentState(t *testing.T) {
 	// ControlPlane and ControlPlaneInfrastructureMachineTemplate objects.
 	controlPlaneInfrastructureMachineTemplate := builder.InfrastructureMachineTemplate(metav1.NamespaceDefault, "cpInfraTemplate").
 		Build()
+	controlPlaneInfrastructureMachineTemplate.SetLabels(map[string]string{clusterv1.ClusterTopologyOwnedLabel: ""})
 	controlPlaneTemplateWithInfrastructureMachine := builder.ControlPlaneTemplate(metav1.NamespaceDefault, "cpTemplateWithInfra1").
 		WithInfrastructureMachineTemplate(controlPlaneInfrastructureMachineTemplate).
 		Build()