Incorrect definitions of <state> in SDF models cause errors on gazebo startup

[Tucker Hermans]

This is definitely true of grasp_scene.world and likely other files derived from that (e.g. looks like it would be an issue in pick_and_place.world

This appears to be because objects like the object_table are defined both as a <model> in the <world> tag and later in the <state> tag. If the correct poses were given in the original definition this should fix it, although I have not fully tested correctly moving other behavior like collision links, etc.

I’ve confirmed this bug on both my machine and the perception-pc for the iiwa setup. I get the following error on the command line when launching:

[ERROR] [1627329505.673546, 2502.645000]: Spawn service failed. Exiting.
[spawn_lbr4-4] process has died [pid 3606, exit code 1, cmd /opt/ros/melodic/lib/gazebo_ros/spawn_model -urdf -param robot_description -model lbr4_reflex -robot_namespace lbr4_reflex __name:=spawn_lbr4 __log:=/home/thermans/.ros/log/d3f3dc2a-ee4b-11eb-8e9b-34e894f0353a/spawn_lbr4-4.log].

And this is the content of the associated log file:

[rospy.client][INFO] 2021-07-26 13:58:23,940: init_node, name[/spawn_lbr4], pid[3606]
[xmlrpc][INFO] 2021-07-26 13:58:23,941: XML-RPC server binding to 0.0.0.0:0
[xmlrpc][INFO] 2021-07-26 13:58:23,941: Started XML-RPC server [http://glados:45683/]
[rospy.init][INFO] 2021-07-26 13:58:23,941: ROS Slave URI: [http://glados:45683/]
[rospy.impl.masterslave][INFO] 2021-07-26 13:58:23,941: _ready: http://glados:45683/
[rospy.registration][INFO] 2021-07-26 13:58:23,942: Registering with master node http://localhost:11311
[xmlrpc][INFO] 2021-07-26 13:58:23,942: xml rpc node: starting XML-RPC server
[rospy.init][INFO] 2021-07-26 13:58:24,041: registered with master
[rospy.rosout][INFO] 2021-07-26 13:58:24,041: initializing /rosout core topic
[rospy.rosout][INFO] 2021-07-26 13:58:24,043: connected to core topic /rosout
[rospy.simtime][INFO] 2021-07-26 13:58:24,044: initializing /clock core topic
[rospy.simtime][INFO] 2021-07-26 13:58:24,046: connected to core topic /clock
[rosout][INFO] 2021-07-26 13:58:24,048: Loading model XML from ros parameter robot_description
[rosout][INFO] 2021-07-26 13:58:24,070: Waiting for service /gazebo/spawn_urdf_model
[rospy.internal][INFO] 2021-07-26 13:58:24,300: topic[/rosout] adding connection to [/rosout], count 0
[rospy.internal][INFO] 2021-07-26 13:58:25,572: topic[/clock] adding connection to [http://glados:35959/], count 0
[rosout][INFO] 2021-07-26 13:58:25,577: Calling service /gazebo/spawn_urdf_model
[rosout][INFO] 2021-07-26 13:58:25,672: Spawn status: SpawnModel: Entity pushed to spawn queue, but spawn service timed out waiting for entity to appear in simulation under the name lbr4_reflex
[rosout][ERROR] 2021-07-26 13:58:25,673: Spawn service failed. Exiting.
[rospy.core][INFO] 2021-07-26 13:58:25,674: signal_shutdown [atexit]
[rospy.internal][INFO] 2021-07-26 13:58:25,676: topic[/rosout] removing connection to /rosout
[rospy.internal][INFO] 2021-07-26 13:58:25,676: topic[/clock] removing connection to http://glados:35959/
[rospy.impl.masterslave][INFO] 2021-07-26 13:58:25,676: atexit

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