Store/Create Bond as a shared_ptr to allow shared_from_this()

In order for Bond to inherit from std::enable_shared_from_this
to allow its lifetime to be managed to avoid a use
after free where its subcriber callback is called
before it has been cleaned up from internal rclcpp
mechanism.

This is being explored either by modification to rclcpp
or using a lambda that protects against the the
member function going out of scope by testing a
weak_ptr to shared_from_this for expiry before
the member function bondStatusCB is called.

Signed-off-by: Mike Wake <[email protected]>

Author: ewak

nav2_util/include/nav2_util/lifecycle_node.hpp

@@ -210,7 +210,7 @@ class LifecycleNode : public rclcpp_lifecycle::LifecycleNode
   void runCleanups();
 
   // Connection to tell that server is still up
-  std::unique_ptr<bond::Bond> bond_{nullptr};
+  std::shared_ptr<bond::Bond> bond_{nullptr};
   double bond_heartbeat_period;
   rclcpp::TimerBase::SharedPtr autostart_timer_;
 };

nav2_util/src/lifecycle_node.cpp

@@ -73,7 +73,7 @@ void LifecycleNode::createBond()
   if (bond_heartbeat_period > 0.0) {
     RCLCPP_INFO(get_logger(), "Creating bond (%s) to lifecycle manager.", this->get_name());
 
-    bond_ = std::make_unique<bond::Bond>(
+    bond_ = std::make_shared<bond::Bond>(
       std::string("bond"),
       this->get_name(),
       shared_from_this());