Use private parameter for parent namespace

Signed-off-by: Luca Della Vedova <lucadv@intrinsic.ai>

Author: luca-della-vedova

nav2_costmap_2d/src/costmap_2d_ros.cpp

@@ -70,8 +70,8 @@ Costmap2DROS::Costmap2DROS(const rclcpp::NodeOptions & options)
     "nav2_costmap_2d::ObstacleLayer",
     "nav2_costmap_2d::InflationLayer"}
 {
-  declare_parameter("map_topic", rclcpp::ParameterValue(std::string("map")));
   is_lifecycle_follower_ = false;
+  declare_parameter("__parent_namespace", std::string(get_namespace()));
   init();
 }
 
@@ -99,9 +99,7 @@ Costmap2DROS::Costmap2DROS(
     "nav2_costmap_2d::ObstacleLayer",
     "nav2_costmap_2d::InflationLayer"}
 {
-  declare_parameter(
-    "map_topic", rclcpp::ParameterValue(
-      (parent_namespace_ == "/" ? "/" : parent_namespace_ + "/") + std::string("map")));
+  declare_parameter("__parent_namespace", parent_namespace);
   init();
 }
 
@@ -114,6 +112,7 @@ void Costmap2DROS::init()
   declare_parameter("footprint_padding", rclcpp::ParameterValue(0.01f));
   declare_parameter("footprint", rclcpp::ParameterValue(std::string("[]")));
   declare_parameter("global_frame", rclcpp::ParameterValue(std::string("map")));
+  declare_parameter("map_topic", rclcpp::ParameterValue(std::string("map")));
   declare_parameter("height", rclcpp::ParameterValue(5));
   declare_parameter("width", rclcpp::ParameterValue(5));
   declare_parameter("lethal_cost_threshold", rclcpp::ParameterValue(100));

nav2_costmap_2d/src/costmap_layer.cpp

@@ -273,9 +273,12 @@ std::string CostmapLayer::joinWithParentNamespace(const std::string & topic)
   }
 
   if (topic[0] != '/') {
-    std::string node_namespace = node->get_namespace();
-    std::string parent_namespace = node_namespace.substr(0, node_namespace.rfind("/"));
-    return parent_namespace + "/" + topic;
+    auto parent_param = node->get_parameter("__parent_namespace");
+    if (parent_param.get_type() != rclcpp::ParameterType::PARAMETER_STRING) {
+      throw std::runtime_error{"__parent_namespace parameter not found or wrong type"};
+    }
+    auto parent_ns = parent_param.as_string();
+    return (parent_ns == "/" ? "/" : parent_ns + "/") + topic;
   }
 
   return topic;