gz sim specific.sdf - run random world if present more than 1

[drfenixion]

Environment

• OS Version: Ubuntu 22.04.4 LTS

binary Gazebo Garden 7.7.0

Description

• Expected behavior:
  I run gz sim (for making any other word). In other terminal i run gz sim fly.sdf. I want to see second Gazebo window as fly.sdf but getting random world (default or fly.sdf).

• Actual behavior:
  Getting random world (default or specific.sdf) in second window of Gazebo. It is unstable cab be many times (1-10) default.sdf or specific.sdf.

If world only 1 (in gz service --list) all works fine.

Steps to reproduce

1. Run gz sim
2. In other terminal run gz sim specific.sdf. Try to do 10 times for get statistics of results (mean run than see result and ctrl + c, after try again).

Output

gz service --list
/gazebo/resource_paths/add
/gazebo/resource_paths/get
/gazebo/resource_paths/resolve
/gazebo/worlds
/gui/camera/view_control
/gui/camera/view_control/reference_visual
/gui/camera/view_control/sensitivity
/gui/copy
/gui/follow
/gui/follow/offset
/gui/move_to
/gui/move_to/pose
/gui/paste
/gui/screenshot
/gui/view/collisions
/gui/view/com
/gui/view/frames
/gui/view/inertia
/gui/view/joints
/gui/view/transparent
/gui/view/wireframes
/marker
/marker/list
/marker_array
/server_control
/world/default/control
/world/default/control/state
/world/default/create
/world/default/create_multiple
/world/default/declare_parameter
/world/default/disable_collision
/world/default/enable_collision
/world/default/entity/system/add
/world/default/generate_world_sdf
/world/default/get_parameter
/world/default/gui/info
/world/default/level/set_performer
/world/default/light_config
/world/default/list_parameters
/world/default/playback/control
/world/default/remove
/world/default/scene/graph
/world/default/scene/info
/world/default/set_parameter
/world/default/set_physics
/world/default/set_pose
/world/default/set_pose_vector
/world/default/set_spherical_coordinates
/world/default/state
/world/default/state_async
/world/default/system/info
/world/default/visual_config
/world/default/wheel_slip
/world/fly/control
/world/fly/control/state
/world/fly/create
/world/fly/create_multiple
/world/fly/declare_parameter
/world/fly/disable_collision
/world/fly/enable_collision
/world/fly/entity/system/add
/world/fly/generate_world_sdf
/world/fly/get_parameter
/world/fly/gui/info
/world/fly/level/set_performer
/world/fly/light_config
/world/fly/list_parameters
/world/fly/playback/control
/world/fly/remove
/world/fly/scene/graph
/world/fly/scene/info
/world/fly/set_parameter
/world/fly/set_physics
/world/fly/set_pose
/world/fly/set_pose_vector
/world/fly/set_spherical_coordinates
/world/fly/state
/world/fly/state_async
/world/fly/system/info
/world/fly/visual_config
/world/fly/wheel_slip

Screen of worlds:
default

fly.sdf

[azeey]

It's not clear to me what you're trying to do. Are you trying to run two different instances of Gazebo with two different worlds at the same time?

[drfenixion]

It is synthetic case only for bug demonstration.

I discovered the bug by accident. I worked a lot with the ros_gz launcher and launched different Gazebo maps. Somehow one of them did not unload (although it should have unloaded) from worlds and for a long time I could not understand why a random map began to open instead of the desired one.

[azeey]

So, the issue is more about accidentally running two instances of Gazebo because, in your example, the ros_gz launcher did not exit properly?

[drfenixion]

I believe it is about unpredictable behaviour (bug) of Gazebo. Because if i run gz sim specific.sdf i expect it should be launched regardless of what worlds were loaded before.

[arjo129]

I think I see the problem here. The client GUI may not pick the right world.