VS Physics Thread crashes

[A31Nesta]

I'm creating a drone (10 spinners in total) and after a while of flying the ship gets stuck in the air and the only way to solve it is to close minecraft and open it again. Looking at the log you can see that the VS Physics thread crashed during the execution of the applyForces function:

[14:16:08] [Physics thread/ERROR] [or.va.co.im.pi.VSPhysicsPipelineBackgroundTask/]: Error in physics pipeline background task
java.util.ConcurrentModificationException: null
    at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1013) ~[?:?] {}
    at java.util.ArrayList$Itr.next(ArrayList.java:967) ~[?:?] {}
    at org.valkyrienskies.tournament.ship.tournamentShipControl.applyForces(tournamentShipControl.java:179) ~[tournament-forge-1.0.0-beta3-0.6+f5dce4613f.jar%2369!/:?] {re:classloading}
    at org.valkyrienskies.core.impl.pipelines.VSPhysicsPipelineStage.tickPhysics(VSPhysicsPipelineStage.kt:138) ~[valkyrienskies-118-forge-2.1.0-beta.10+d84531555f.jar%2370!/:?] {re:classloading}
    at org.valkyrienskies.core.impl.pipelines.VSPipelineImpl.tickPhysics(VSPipelineImpl.kt:109) ~[valkyrienskies-118-forge-2.1.0-beta.10+d84531555f.jar%2370!/:?] {re:classloading}
    at org.valkyrienskies.core.impl.pipelines.VSPhysicsPipelineBackgroundTask.run(VSPhysicsPipelineBackgroundTask.kt:75) [valkyrienskies-118-forge-2.1.0-beta.10+d84531555f.jar%2370!/:?] {re:classloading}
    at org.valkyrienskies.core.impl.pipelines.VSPipelineImpl$physicsThread$1.invoke(VSPipelineImpl.kt:65) [valkyrienskies-118-forge-2.1.0-beta.10+d84531555f.jar%2370!/:?] {re:classloading}
    at org.valkyrienskies.core.impl.pipelines.VSPipelineImpl$physicsThread$1.invoke(VSPipelineImpl.kt:64) [valkyrienskies-118-forge-2.1.0-beta.10+d84531555f.jar%2370!/:?] {re:classloading}
    at kotlin.concurrent.ThreadsKt$thread$thread$1.run(Thread.kt:30) [kotlinforforge-3.11.0-all.jar%2363!/:?] {}
[14:16:08] [Physics thread/ERROR] [or.va.co.im.pi.VSPhysicsPipelineBackgroundTask/]: !!!!!!! VS PHYSICS THREAD CRASHED !!!!!!!

I'm using

• Minecraft 1.18.2
• Forge 40.2.0
• Valkyien Skies 2.1.0-beta.10+d84531555f
• Tournament 1.0.0-beta3-0.6+f5dce4613f (Beta 3 Snapshot 0.6)
• Takeoff 1.0.0-beta1+308678c5c5

and also CC: Tweaked and Valkyrien Computers but they're not really related to this problem because I had this exact same problem before installing computercraft while playing with my previous drone (9 spinners).

[alex-s168]

im 99% sure thats a vs2 bug

[A31Nesta]

I thought it was because of the applyForces function that apparently runs on the physics thread. This function accesses some global variables so that's why I thought that the problem was in tournament and not vs2

[Rubydesic]

Yes, this is a race condition caused by tournament not using thread safe data structures to hold the balloons, spinners, etc. Maybe consider using a ConcurrentHashMap.newKeySet() instead of an ArrayList, which is both faster and also has O(1) delete as opposed to O(n) for ArrayList

https://github.com/ConstantDust/VS_tournament-Vintage/blob/f5dce4613ff974661674b8f5703de2152785d76b/common/src/main/kotlin/org/valkyrienskies/tournament/ship/tournamentShipControl.kt#L38-L41

[Rubydesic]

I see you use a thread-safe CopyOnWriteArrayList for Pulses but not for anything else for some reason.

[alex-s168]

ah lol

im gonna fix that sometime