Add note on multirobot refactor to migration guide

configuration/packages/configuring-costmaps.rst

@@ -90,17 +90,6 @@ Costmap2D ROS Parameters
   Description
     Minimum cost of an occupancy grid map to be considered a lethal obstacle.
 
-:map_topic:
-
-  ============== =======
-  Type           Default
-  -------------- -------
-  string         "map"   
-  ============== =======
-
-  Description
-    Topic of map from map_server or SLAM.
-
 :map_vis_z:
 
   ============== =======

configuration/packages/costmap-plugins/obstacle.rst

@@ -86,6 +86,14 @@ This costmap layer implements a plugin that uses 2D raycasting for 2D lidars, de
   Description
     Topic of data.
 
+  Relative topics will be relative to the node's parent namespace.
+  For example, if you specify `topic: scan` in the `obstacle_layer` of a `local_costmap` and you launch your bringup with a `tb4` namespace:
+
+  * User chosen namespace is `tb4`.
+  * User chosen topic is `scan`.
+  * Topic will be remapped to `/tb4/scan` without `local_costmap`.
+  * Use global topic `/scan` if you do not wish the node namespace to apply.
+
 :``<obstacle layer>``. ``<data source>``.sensor_frame:
 
   ====== =======

configuration/packages/costmap-plugins/range.rst

@@ -29,6 +29,14 @@ This costmap layer implements a plugin that processes sonar, IR, or other 1-D se
   Description
     Range topics to subscribe to.
 
+  Relative topics will be relative to the node's parent namespace.
+  For example, if you specify `topics: [range1, /range2]` in the `range_layer` of a `local_costmap` and you launch your bringup with a `tb4` namespace:
+
+  * User chosen namespace is `tb4`.
+  * User chosen topics are [`range1`, `/range2`].
+  * Topic will be remapped to `/tb4/range1`, without `local_costmap`, and `/range2`.
+  * Use global topics such as `/range2` if you do not wish the node namespace to apply.
+
 :``<range layer>``.phi:
 
   ====== =======

configuration/packages/costmap-plugins/static.rst

@@ -71,4 +71,12 @@ This implements a costmap layer taking in a map from either SLAM or ``map_server
   ====== =======
 
   Description
-    Map topic to subscribe to. If left empty the map topic will default to the global `map_topic` parameter in `costmap_2d_ros`.
+    Map topic to subscribe to. If left empty the map topic will default to the global `map_topic` parameter in `costmap_2d_ros`.
+
+  Relative topics will be relative to the node's parent namespace.
+  For example, if you specify `map_topic: map` in the `static_layer` of a `global_costmap` and you launch your bringup with a `tb4` namespace:
+
+  * User chosen namespace is `tb4`.
+  * User chosen topic is `map`.
+  * Topic will be remapped to `/tb4/map` without `global_costmap`.
+  * Use global topic `/map` if you do not wish the node namespace to apply.

configuration/packages/costmap-plugins/voxel.rst

@@ -151,6 +151,14 @@ This costmap layer implements a plugin that uses 3D raycasting for depth, 3D, or
   Description
     Topic of data.
 
+  Relative topics will be relative to the node's parent namespace.
+  For example, if you specify `topic: scan` in the `voxel_layer` of a `local_costmap` and you launch your bringup with a `tb4` namespace:
+
+  * User chosen namespace is `tb4`.
+  * User chosen topic is `scan`.
+  * Topic will be remapped to `/tb4/scan` without `local_costmap`.
+  * Use global topic `/scan` if you do not wish the node namespace to apply.
+
 :``<voxel layer>``. ``<data source>``.sensor_frame:
 
   ====== =======

migration/Jazzy.rst

@@ -107,4 +107,70 @@ In `PR #4752 <https://github.com/ros-navigation/navigation2/pull/4752>`_ an opti
 
 Default value:
 
-- true
+- true
+
+Revamped multirobot bringup and config files to use namespaces
+**************************************************************
+
+In `PR #4715 <https://github.com/ros-navigation/navigation2/pull/4715>`_ multirobot bringup and the use of namespaces were overhauled to be compatible out of the box with ROS namespaces and remove custom logic, specifically:
+
+* The ``use_namespace`` parameter has been removed from ``nav2_bringup`` launch files. The ``namespace`` parameter will now always be used and default to ``/`` for "global namespace".
+* There is now a single rviz config file for both normal and namespaced robots. Topics have been changed to a relative path (i.e. ``/map`` -> ``map``) and the rviz ``namespace`` will be added automatically.
+* There is now a single ``nav2_params.yaml`` config file for both single and multirobot bringup. All the topics have been changed to relative (i.e. ``/scan`` -> ``scan``).
+
+Note that some plugins / nodes might have their own local namespace. This is the case for ``CostmapLayer`` which will be in a ``/ns/[layer_name]`` namespace. For these, a new function ``joinWithParentNamespace`` has been added to make sure joining relative paths results in ``/ns/topic_name`` rather than ``/ns/[layer_name]/topic_name``.
+
+If your use case doesn't require multiple robots, keeping absolute paths in your ``nav2_params.yaml`` config file and rviz config file will preserve existing behavior.
+
+For example, if you specify ``topic: scan`` in the ``voxel_layer`` of a ``local_costmap`` and you launch your bringup with a ``tb4`` namespace:
+
+* User chosen namespace is ``tb4``.
+* User chosen topic is ``scan``.
+* Topic will be remapped to ``/tb4/scan`` without ``local_costmap``.
+* Use global topic ``/scan`` if you do not wish the node namespace to apply
+
+Removed global map_topic from Costmap node
+******************************************
+
+In `PR #4715 <https://github.com/ros-navigation/navigation2/pull/4715>`_ the global ``map_topic`` parameter has been removed from the ``Costmap2DROS`` node. This parameterwas only used in the ``StaticLayer`` and should be defined as a parameter local to the ``StaticLayer`` instead, for example:
+
+.. code-block:: yaml
+
+  global_costmap:
+    global_costmap:
+      ros__parameters:
+        [...]
+        # Not supported anymore
+        map_topic: my_map
+        static_layer:
+          plugin: "nav2_costmap_2d::StaticLayer"
+          map_subscribe_transient_local: True
+          # Do this instead
+          map_topic: my_map
+
+Simplified Costmap2DROS constructors
+************************************
+
+The following constructors for ``Costmap2DROS`` have been removed:
+
+.. code-block:: cpp
+
+   explicit Costmap2DROS(
+    const std::string & name,
+    const std::string & parent_namespace,
+    const std::string & local_namespace,
+    const bool & use_sim_time);
+
+   explicit Costmap2DROS(const std::string & name, const bool & use_sim_time = false);
+
+They have been consolidated into a single one:
+
+.. code-block:: cpp
+
+   explicit Costmap2DROS(
+    const std::string & name,
+    const std::string & parent_namespace = "/",
+    const bool & use_sim_time = false);
+
+The ``local_namespace`` parameter has been removed and is now automatically set to the node's name (which is what the second removed constructor did).
+Parameters ``parent_namespace`` / ``use_sim_time`` both provide default values to maintain the ability of creating a ``Costmap2DROS`` object by just specifying a name.

tuning/index.rst

@@ -162,8 +162,7 @@ Within ``nav2_bringup``, there is a main entryfile ``tb3_simulation_launch.py``.
 - ``use_robot_state_pub`` : Whether or not to start the robot state publisher to publish the robot's URDF transformations to TF2. Defaults to ``true`` to publish the robot's TF2 transformations.
 - ``use_rviz`` : Whether or not to launch rviz for visualization. Defaults to ``true`` to show rviz.
 - ``headless`` : Whether or not to launch the Gazebo front-end alongside the background Gazebo simulation. Defaults to ``true`` to display the Gazebo window.
-- ``namespace`` : The namespace to launch robots into, if need be.
-- ``use_namespace`` : Whether or not to launch robots into this namespace. Default ``false`` and uses global namespace for single robot.
+- ``namespace`` : The namespace to launch robots into.
 - ``robot_name`` : The name of the robot to launch.
 - ``robot_sdf`` : The filepath to the robot's gazebo configuration file containing the Gazebo plugins and setup to simulate the robot system.
 - ``x_pose``, ``y_pose``, ``z_pose``, ``roll``, ``pitch``, ``yaw`` : Parameters to set the initial position of the robot in the simulation.