xacro: in-order processing became default in ROS MeLodic.

edit

I have exported an urdf file from solidwork and change it into xacro file ,but I meet some troubles when i launched it. The original urdf file(display.launch) can be launched normally. When I launch my xacro file, it can't works.

The problem is within the used launch file (robot.launch):

<launch>
  <arg name="model" default="$(find xacro)/xacro --inorder '$(find myarm)/urdf/xacro/total.xacro'" />
  <arg  name="gui"  default="True" />

  <param name="robot_description" command="$(arg model)" />

  <param name="use_gui"   value="$(arg gui)" />

  <node  name="joint_state_publisher"  pkg="joint_state_publisher"  type="joint_state_publisher" />

  <node  name="robot_state_publisher"  pkg="robot_state_publisher"   type="state_publisher" />

  <node  name="rviz"  pkg="rviz"   type="rviz"   args="-d $(find model)/urdf.rviz" />
</launch>

The log is following.

[roslaunch][INFO] 2020-03-30 21:00:25,178: starting in server mode
[roslaunch.parent][INFO] 2020-03-30 21:00:25,178: starting roslaunch parent run
[roslaunch][INFO] 2020-03-30 21:00:25,178: loading roscore config file /opt/ros/melodic/etc/ros/roscore.xml
[roslaunch][INFO] 2020-03-30 21:00:25,487: Added core node of type [rosout/rosout] in namespace [/]
[roslaunch.config][INFO] 2020-03-30 21:00:25,487: loading config file /home/heho/catkin_ws/src/myarm/launch/robot.launch
[roslaunch][INFO] 2020-03-30 21:00:25,675: Added node of type [joint_state_publisher/joint_state_publisher] in namespace [/]
[roslaunch][INFO] 2020-03-30 21:00:25,675: Added node of type [robot_state_publisher/state_publisher] in namespace [/]
[roslaunch][ERROR] 2020-03-30 21:00:25,675: Resource not found: model
ROS path [0]=/opt/ros/melodic/share/ros
ROS path [1]=/home/heho/catkin_ws/src
ROS path [2]=/opt/ros/melodic/share
[roslaunch][ERROR] 2020-03-30 21:00:25,675: The traceback for the exception was written to the log file
[roslaunch][ERROR] 2020-03-30 21:00:25,679: Traceback (most recent call last):
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/__init__.py", line 330, in main
    p.start()
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/parent.py", line 289, in start
    self._start_infrastructure()
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/parent.py", line 238, in _start_infrastructure
    self._load_config()
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/parent.py", line 144, in _load_config
    roslaunch_strs=self.roslaunch_strs, verbose=self.verbose)
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/config.py", line 460, in load_config_default
    loader.load(f, config, argv=args, verbose=verbose)
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 761, in load
    self._load_launch(launch, ros_config, is_core=core, filename=filename, argv=argv, verbose=verbose)
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 733, in _load_launch
    self._recurse_load(ros_config, launch.childNodes, self.root_context, None, is_core, verbose)
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 671, in _recurse_load
    n = self._node_tag(tag, context, ros_config, default_machine, verbose=verbose)
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 96, in call
    return f(*args, **kwds)
  File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/xmlloader.py", line 390, in _node_tag
    'launch-prefix ...