No longer create nodes for child loggers on Humble

moveit_core/utils/src/logger.cpp

@@ -69,29 +69,19 @@ const rclcpp::Logger& get_logger()
 
 rclcpp::Logger make_child_logger(const std::string& name)
 {
-  // On versions of ROS older than Iron we need to create a node for each child logger
-  // Remove once Humble is EOL
-  // References:
-  // Use parent logger (rcl PR) - https://github.com/ros2/rcl/pull/921
-  // Request for backport (rclpy issue) - https://github.com/ros2/rclpy/issues/1131
-  // MoveIt PR that added this - https://github.com/ros-planning/moveit2/pull/2445
+  // On versions of ROS older than Iron child loggers do not log to rosout unless there
+  // is a node of the same name. See: https://github.com/ros2/rcl/pull/921
+  // We attempted to solve this problem by creating nodes for each child logger
+  // as suggested here: https://github.com/ros2/rclpy/issues/1131
+  // The side-affects of creating many nodes caused problems with many duplicate
+  // ros nodes and creating many services per-node that slow DDS discovery.
+  //
+  // To deal with the problem of loss of namespacing on Humble see this comment:
+  // https://github.com/ros-planning/moveit2/issues/2376#issuecomment-1781586851
+  // TL;DR is to use the source location information in /rosout
+  //
 #if !RCLCPP_VERSION_GTE(21, 0, 3)
-  static std::unordered_map<std::string, std::shared_ptr<rclcpp::Node>> child_nodes;
-  if (child_nodes.find(name) == child_nodes.end())
-  {
-    std::string ns = get_logger().get_name();
-    try
-    {
-      child_nodes[name] = std::make_shared<rclcpp::Node>(name, ns);
-    }
-    catch (...)
-    {
-      // rclcpp::init was not called so rcl context is null, return non-node logger
-      auto logger = rclcpp::get_logger(ns.append(".").append(name));
-      RCLCPP_WARN(logger, "rclcpp::init was not called, messages from this logger may be missing from /rosout");
-      return logger;
-    }
-  }
+  return get_global_logger_ref();
 #endif
 
   return get_global_logger_ref().get_child(name);