icleanupcomponentdata-runtime

To safely release external resources during Unity DOTS entity destruction, preserve an ICleanupComponentData component after calling DestroyEntity. This allows a dedicated cleanup system to detect the destroyed entity, explicitly free handles like GPU buffers or physics objects, and then remove the component to finalize destruction.

The tombstone pattern in Unity DOTS uses an ICleanupComponentData component that survives DestroyEntity, keeping the entity observable for cleanup systems. This mechanism ensures external resources such as audio handles, spatial index entries, or registry slots are explicitly released before the entity is truly destroyed.

To detect destroyed entities and prevent processing live ones, query for entities using .WithNone<MainComponent>() in your cleanup system. This enforces query correctness by targeting only entities whose primary component is gone, ensuring you handle resource release exclusively for destroyed entities.

The correct system lifecycle pattern for resource-safe entity destruction requires three stages: an acquire or setup system, a detection system using WithNone on the main component, and a release system that frees resources and calls RemoveComponent to trigger final destruction.

Your Unity DOTS cleanup system likely processes live entities because the query lacks .WithNone<MainComponent>(). Enforcing this query constraint strictly targets destroyed entities that still retain their ICleanupComponentData component, preventing live entities from entering the resource release logic.

Yes, you can use ICleanupComponentData to free physics bodies, GPU buffers, audio instances, and spatial index entries at runtime. By preserving this component after DestroyEntity, a cleanup system can detect the destroyed entity and execute the explicit release logic required for these external resources.