make all destructors virtual

rclcpp/include/rclcpp/client.hpp

@@ -54,7 +54,7 @@ public:
   : node_handle_(node_handle), client_handle_(client_handle), service_name_(service_name)
   {}
 
-  ~ClientBase()
+  virtual ~ClientBase()
   {
     if (client_handle_) {
       if (rmw_destroy_client(client_handle_) != RMW_RET_OK) {

rclcpp/include/rclcpp/executors/multi_threaded_executor.hpp

@@ -48,7 +48,7 @@ public:
     }
   }
 
-  ~MultiThreadedExecutor() {}
+  virtual ~MultiThreadedExecutor() {}
 
   void
   spin()

rclcpp/include/rclcpp/executors/single_threaded_executor.hpp

@@ -42,7 +42,7 @@ public:
 
   SingleThreadedExecutor() {}
 
-  ~SingleThreadedExecutor() {}
+  virtual ~SingleThreadedExecutor() {}
 
   void spin()
   {

rclcpp/include/rclcpp/publisher.hpp

@@ -45,7 +45,7 @@ public:
   : node_handle_(node_handle), publisher_handle_(publisher_handle)
   {}
 
-  ~Publisher()
+  virtual ~Publisher()
   {
     if (publisher_handle_) {
       if (rmw_destroy_publisher(node_handle_.get(), publisher_handle_) != RMW_RET_OK) {

rclcpp/include/rclcpp/service.hpp

@@ -53,7 +53,7 @@ public:
   : node_handle_(node_handle), service_handle_(service_handle), service_name_(service_name)
   {}
 
-  ~ServiceBase()
+  virtual ~ServiceBase()
   {
     if (service_handle_) {
       if (rmw_destroy_service(service_handle_) != RMW_RET_OK) {

rclcpp/include/rclcpp/subscription.hpp

@@ -59,7 +59,7 @@ public:
     (void)ignore_local_publications_;
   }
 
-  ~SubscriptionBase()
+  virtual ~SubscriptionBase()
   {
     if (subscription_handle_) {
       if (rmw_destroy_subscription(node_handle_.get(), subscription_handle_) != RMW_RET_OK) {

rclcpp/include/rclcpp/timer.hpp

@@ -64,7 +64,7 @@ public:
     }
   }
 
-  ~TimerBase()
+  virtual ~TimerBase()
   {
     if (guard_condition_) {
       if (rmw_destroy_guard_condition(guard_condition_) != RMW_RET_OK) {
@@ -107,7 +107,7 @@ public:
     thread_ = std::thread(&GenericTimer<Clock>::run, this);
   }
 
-  ~GenericTimer()
+  virtual ~GenericTimer()
   {
     cancel();
     thread_.join();