ApplyLinkWrenchTestFixture.PersistentFromTopic test is flaky

[scpeters]

Environment

• OS Version: Ubuntu 24.04
• Source or binary build? source build of 9cfe829 from Remove major version from package name #2726 targeting gz-sim10

Description

• Expected behavior: INTEGRATION_apply_link_wrench_system test should pass consistently
• Actual behavior: it fails sometimes

Steps to reproduce

1. Build from source
2. Run the stress program in one terminal (e.g. stress -c 8 -i 8)
3. In another terminal, run the test multiple times (from the build folder: ctest -R apply_link -VV --repeat-until-fail 100)
4. Observe failures

Output

https://build.osrfoundation.org/job/gz_sim-ci-pr_any-noble-amd64/368/testReport/junit/(root)/ApplyLinkWrenchTestFixture/PersistentFromTopic/

99: [ RUN      ] ApplyLinkWrenchTestFixture.PersistentFromTopic
99: (2025-01-23 07:50:13.143) [info] [Server.cc:145] Loading SDF world file[/home/jenkins/workspace/gz_sim-ci-pr_any-noble-amd64/gz-sim/test/worlds/apply_link_wrench.sdf].
99: (2025-01-23 07:50:13.197) [info] [SystemManager.cc:54] Serving entity system service on [/entity/system/add]
99: (2025-01-23 07:50:13.209) [debug] [Physics.cc:877] Loaded [gz::physics::dartsim::Plugin] from library [/usr/lib/x86_64-linux-gnu/gz-physics-8/engine-plugins/libgz-physics-dartsim-plugin.so]
99: (2025-01-23 07:50:13.209) [debug] [SystemManager.cc:80] Loaded system [gz::sim::systems::Physics] for entity [1]
99: (2025-01-23 07:50:13.209) [debug] [ApplyLinkWrench.cc:344] Queueing persistent wrench:
99: entity {
99:   name: "model1"
99:   type: MODEL
99: }
99: wrench {
99:   force {
99:     x: 50
99:   }
99:   torque {
99:     z: 0.5
99:   }
99: }
99: 
99: (2025-01-23 07:50:13.209) [debug] [ApplyLinkWrench.cc:344] Queueing persistent wrench:
99: entity {
99:   name: "model2::link"
99:   type: LINK
99: }
99: wrench {
99:   force {
99:     x: -100
99:   }
99:   torque {
99:     z: -1
99:   }
99: }
99: 
99: (2025-01-23 07:50:13.210) [info] [ApplyLinkWrench.cc:206] Listening to instantaneous wrench commands in [/world/apply_link_wrench/wrench]
99: (2025-01-23 07:50:13.210) [info] [ApplyLinkWrench.cc:217] Listening to persistent wrench commands in [/world/apply_link_wrench/wrench/persistent]
99: (2025-01-23 07:50:13.210) [info] [ApplyLinkWrench.cc:228] Listening to wrench clear commands in [/world/apply_link_wrench/wrench/clear]
99: (2025-01-23 07:50:13.210) [debug] [SystemManager.cc:80] Loaded system [gz::sim::systems::ApplyLinkWrench] for entity [1]
99: (2025-01-23 07:50:13.210) [info] [LevelManager.cc:641] Loaded level [default]
99: (2025-01-23 07:50:13.210) [debug] [ServerConfig.cc:1025] Loading (3) plugins from file [/home/jenkins/workspace/gz_sim-ci-pr_any-noble-amd64/build/test/fake_home/.gz/sim/10/server.config]
99: (2025-01-23 07:50:13.210) [debug] [SimulationRunner.cc:1645] Additional plugins to load:
99: (2025-01-23 07:50:13.210) [debug] [SimulationRunner.cc:1648] gz::sim::systems::UserCommands gz-sim-user-commands-system
99: (2025-01-23 07:50:13.210) [debug] [SimulationRunner.cc:1648] gz::sim::systems::SceneBroadcaster gz-sim-scene-broadcaster-system
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:664] Create service on [/world/apply_link_wrench/create]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:671] Remove service on [/world/apply_link_wrench/remove]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:678] Pose service on [/world/apply_link_wrench/set_pose]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:686] Pose service on [/world/apply_link_wrench/set_pose_vector]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:693] Light configuration service on [/world/apply_link_wrench/light_config]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:719] Physics service on [/world/apply_link_wrench/set_physics]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:727] SphericalCoordinates service on [/world/apply_link_wrench/set_spherical_coordinates]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:736] Enable collision service on [/world/apply_link_wrench/enable_collision]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:745] Disable collision service on [/world/apply_link_wrench/disable_collision]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:754] Material service on [/world/apply_link_wrench/visual_config]
99: (2025-01-23 07:50:13.211) [info] [UserCommands.cc:762] Material service on [/world/apply_link_wrench/wheel_slip]
99: (2025-01-23 07:50:13.212) [debug] [SystemManager.cc:80] Loaded system [gz::sim::systems::UserCommands] for entity [1]
99: (2025-01-23 07:50:13.212) [debug] [SystemManager.cc:80] Loaded system [gz::sim::systems::SceneBroadcaster] for entity [1]
99: (2025-01-23 07:50:13.212) [info] [SimulationRunner.cc:260] Serving world controls on [/world/apply_link_wrench/control], [/world/apply_link_wrench/control/state] and [/world/apply_link_wrench/playback/control]
99: (2025-01-23 07:50:13.212) [info] [SimulationRunner.cc:286] Serving GUI information on [/world/apply_link_wrench/gui/info]
99: (2025-01-23 07:50:13.212) [info] [SimulationRunner.cc:289] World [apply_link_wrench] initialized with [default_physics] physics profile.
99: (2025-01-23 07:50:13.212) [info] [SimulationRunner.cc:296] Serving world SDF generation service on [/world/apply_link_wrench/generate_world_sdf]
99: (2025-01-23 07:50:13.212) [info] [ServerPrivate.cc:332] Serving world names on [/gazebo/worlds]
99: (2025-01-23 07:50:13.212) [info] [ServerPrivate.cc:345] Resource path add service on [/gazebo/resource_paths/add].
99: (2025-01-23 07:50:13.212) [info] [ServerPrivate.cc:358] Resource path get service on [/gazebo/resource_paths/get].
99: (2025-01-23 07:50:13.212) [info] [ServerPrivate.cc:373] Resource path resolve service on [/gazebo/resource_paths/resolve].
99: (2025-01-23 07:50:13.213) [info] [ServerPrivate.cc:387] Resource paths published on [/gazebo/resource_paths].
99: (2025-01-23 07:50:13.213) [info] [ServerPrivate.cc:400] Server control service on [/server_control].
99: (2025-01-23 07:50:13.213) [info] [SimulationRunner.cc:743] Found no publishers on /stats, adding root stats topic
99: (2025-01-23 07:50:13.213) [info] [SimulationRunner.cc:777] Found no publishers on /clock, adding root clock topic
99: (2025-01-23 07:50:13.213) [debug] [SimulationRunner.cc:542] Creating PostUpdate worker threads: 3
99: (2025-01-23 07:50:13.213) [debug] [SimulationRunner.cc:553] Creating postupdate worker thread (0)
99: (2025-01-23 07:50:13.213) [debug] [SimulationRunner.cc:553] Creating postupdate worker thread (1)
99: (2025-01-23 07:50:13.214) [debug] [ApplyLinkWrench.cc:344] Queueing persistent wrench:
99: entity {
99:   name: "model3"
99:   type: MODEL
99: }
99: wrench {
99:   force {
99:     x: 50
99:   }
99:   torque {
99:     z: 0.5
99:   }
99: }
99: 
99: (2025-01-23 07:50:13.214) [debug] [ApplyLinkWrench.cc:344] Queueing persistent wrench:
99: entity {
99:   name: "model4::link"
99:   type: LINK
99: }
99: wrench {
99:   force {
99:     x: -100
99:   }
99:   torque {
99:     z: -1
99:   }
99: }
99: 
99: (2025-01-23 07:50:13.215) [info] [SceneBroadcaster.cc:634] Serving scene information on [/world/apply_link_wrench/scene/info]
99: (2025-01-23 07:50:13.216) [info] [SceneBroadcaster.cc:643] Serving graph information on [/world/apply_link_wrench/scene/graph]
99: (2025-01-23 07:50:13.216) [info] [SceneBroadcaster.cc:654] Serving full state on [/world/apply_link_wrench/state]
99: (2025-01-23 07:50:13.216) [info] [SceneBroadcaster.cc:663] Serving full state (async) on [/world/apply_link_wrench/state_async]
99: (2025-01-23 07:50:13.216) [info] [SceneBroadcaster.cc:671] Publishing scene information on [/world/apply_link_wrench/scene/info]
99: (2025-01-23 07:50:13.216) [info] [SceneBroadcaster.cc:680] Publishing entity deletions on [/world/apply_link_wrench/scene/deletion]
99: (2025-01-23 07:50:13.216) [info] [SceneBroadcaster.cc:689] Publishing state changes on [/world/apply_link_wrench/state]
99: (2025-01-23 07:50:13.216) [info] [SceneBroadcaster.cc:700] Publishing pose messages on [/world/apply_link_wrench/pose/info]
99: (2025-01-23 07:50:13.216) [info] [SceneBroadcaster.cc:711] Publishing dynamic pose messages on [/world/apply_link_wrench/dynamic_pose/info]
99: /home/jenkins/workspace/gz_sim-ci-pr_any-noble-amd64/gz-sim/test/integration/apply_link_wrench_system.cc:152: Failure
99: Expected: (nullptr) != (wrenchComp3), actual: (nullptr) vs NULL
99: /home/jenkins/workspace/gz_sim-ci-pr_any-noble-amd64/gz-sim/test/integration/apply_link_wrench_system.cc:156: Failure
99: Expected: (nullptr) != (wrenchComp4), actual: (nullptr) vs NULL
99: /home/jenkins/workspace/gz_sim-ci-pr_any-noble-amd64/gz-sim/test/integration/apply_link_wrench_system.cc:166: Failure
99: The difference between 50.0 and linAccel3.value().X() is 50, which exceeds 10e-4, where
99: 50.0 evaluates to 50,
99: linAccel3.value().X() evaluates to 0, and
99: 10e-4 evaluates to 0.001.
99: /home/jenkins/workspace/gz_sim-ci-pr_any-noble-amd64/gz-sim/test/integration/apply_link_wrench_system.cc:167: Failure
99: The difference between -100.0 and linAccel4.value().X() is 100, which exceeds 10e-4, where
99: -100.0 evaluates to -100,
99: linAccel4.value().X() evaluates to 0, and
99: 10e-4 evaluates to 0.001.
99: (2025-01-23 07:50:13.619) [debug] [ApplyLinkWrench.cc:256] Clearing persistent wrench for entity [10]
99: (2025-01-23 07:50:13.619) [debug] [ApplyLinkWrench.cc:256] Clearing persistent wrench for entity [14]
99: (2025-01-23 07:50:13.723) [debug] [SimulationRunner.cc:569] Exiting postupdate worker thread (0)
99: (2025-01-23 07:50:13.723) [debug] [SimulationRunner.cc:569] Exiting postupdate worker thread (1)
99: [  FAILED  ] ApplyLinkWrenchTestFixture.PersistentFromTopic (599 ms)