ingress: Avoid potential nil pointer during cleanup

As part of garbage collected steps in default Ingress class changes, the
garbage collection process kicks off based on our translation logic.
However, depending on which load-balancer mode is used, the translated
service or endpoint might be nil. This commit is to make sure that we
only performs GC if applicable. Ideally, only Service and Endpoint objs
should be checked, but for readability, nil check for CEC object is also
done.

Fixes: 85671ad
Fixes: #24347
Signed-off-by: Tam Mach <tam.mach@cilium.io>

operator/pkg/ingress/ingress.go

@@ -654,16 +654,22 @@ func (ic *Controller) garbageCollectOwnedResources(ing *slim_networkingv1.Ingres
 		return err
 	}
 
-	if err := deleteObjectIfExists(cec, ic.envoyConfigManager.getByKey, ic.clientset.CiliumV2().CiliumEnvoyConfigs(cec.GetNamespace()).Delete); err != nil {
-		return err
+	if cec != nil {
+		if err := deleteObjectIfExists(cec, ic.envoyConfigManager.getByKey, ic.clientset.CiliumV2().CiliumEnvoyConfigs(cec.GetNamespace()).Delete); err != nil {
+			return err
+		}
 	}
 
-	if err := deleteObjectIfExists(svc, ic.serviceManager.getByKey, ic.clientset.CoreV1().Services(svc.GetNamespace()).Delete); err != nil {
-		return err
+	if svc != nil {
+		if err := deleteObjectIfExists(svc, ic.serviceManager.getByKey, ic.clientset.CoreV1().Services(svc.GetNamespace()).Delete); err != nil {
+			return err
+		}
 	}
 
-	if err := deleteObjectIfExists(ep, ic.endpointManager.getByKey, ic.clientset.CoreV1().Endpoints(ep.GetNamespace()).Delete); err != nil {
-		return err
+	if ep != nil {
+		if err := deleteObjectIfExists(ep, ic.endpointManager.getByKey, ic.clientset.CoreV1().Endpoints(ep.GetNamespace()).Delete); err != nil {
+			return err
+		}
 	}
 
 	return nil