Hi!

I recently tried to create a game on dots and I used Unty Physics Sample as reference for few things.
I found collider event example there which can be incorrect.

I am talking about sample below:
`[UpdateAfter(typeof(EndFramePhysicsSystem))]
unsafe public class CollisionEventImpulseSystem : JobComponentSystem
{
BuildPhysicsWorld m_BuildPhysicsWorldSystem;
StepPhysicsWorld m_StepPhysicsWorldSystem;

EntityQuery ImpulseGroup;
protected override void OnCreate()
{
    m_BuildPhysicsWorldSystem = World.GetOrCreateSystem<BuildPhysicsWorld>();
    m_StepPhysicsWorldSystem = World.GetOrCreateSystem<StepPhysicsWorld>();
    ImpulseGroup = GetEntityQuery(new EntityQueryDesc
    {
        All = new ComponentType[] { typeof(CollisionEventImpulse), }
    });
}

[BurstCompile]
struct CollisionEventImpulseJob : ICollisionEventsJob
{
    [ReadOnly] public ComponentDataFromEntity<CollisionEventImpulse> ColliderEventImpulseGroup;
    public ComponentDataFromEntity<PhysicsVelocity> PhysicsVelocityGroup;

    public void Execute(CollisionEvent collisionEvent)
    {
        Entity entityA = collisionEvent.Entities.EntityA;
        Entity entityB = collisionEvent.Entities.EntityB;

        bool isBodyADynamic = PhysicsVelocityGroup.Exists(entityA);
        bool isBodyBDynamic = PhysicsVelocityGroup.Exists(entityB);

        bool isBodyARepulser = ColliderEventImpulseGroup.Exists(entityA);
        bool isBodyBRepulser = ColliderEventImpulseGroup.Exists(entityB);

        if(isBodyARepulser && isBodyBDynamic)
        {
            var impulseComponent = ColliderEventImpulseGroup[entityA];
            var velocityComponent = PhysicsVelocityGroup[entityB];
            velocityComponent.Linear = impulseComponent.Impulse;
            PhysicsVelocityGroup[entityB] = velocityComponent;
        }
        if (isBodyBRepulser && isBodyADynamic)
        {
            var impulseComponent = ColliderEventImpulseGroup[entityB];
            var velocityComponent = PhysicsVelocityGroup[entityA];
            velocityComponent.Linear = impulseComponent.Impulse;
            PhysicsVelocityGroup[entityA] = velocityComponent;
        }
    }
}

protected override JobHandle OnUpdate(JobHandle inputDeps)
{
    JobHandle jobHandle = new CollisionEventImpulseJob
    {
        ColliderEventImpulseGroup = GetComponentDataFromEntity<CollisionEventImpulse>(true),
        PhysicsVelocityGroup = GetComponentDataFromEntity<PhysicsVelocity>(),
    }.Schedule(m_StepPhysicsWorldSystem.Simulation, 
                ref m_BuildPhysicsWorldSystem.PhysicsWorld, inputDeps);

    return jobHandle;
}

} `

It may produce job dependency problems. You can look at this post on unity forum about this problems: Post on Unity Forum