stride3d/stride · error · InvalidOperationException

Cannot dispose while a job is in flight

Error message

Cannot dispose while a job is in flight

What it means

This Dispose implementation refuses to release the worker buffer pools while a dispatch job is still in flight: _managedContext or _unmanagedContext is non-null, meaning a dispatch is between begin and completion. Disposing then would free memory the running job still uses, so it throws InvalidOperationException instead of corrupting state.

Solutions

1. Wait for all in-flight jobs to complete (join the dispatch / end the job) before calling Dispose().
2. Ensure shutdown ordering: stop the simulation loop, then dispose the dispatcher.
3. Synchronize disposal with the code path that starts jobs (lock or task completion await).

Example fix

// before
dispatcher.Dispose(); // while job running
// after
await taskUsingDispatcher; // or dispatcher.EndDispatch(...)
dispatcher.Dispose();

bool isIdle = dispatcher.HasNoInFlightJobs; // expose/check before disposing
canDispose = isIdle || _disposed;

try { dispatcher.Dispose(); } catch (InvalidOperationException) { await inFlightTask; dispatcher.Dispose(); }

When it happens

Trigger: Calling DispatcherWrapper.Dispose() from another thread while an outstanding dispatch (Begin/End job) has not finished, or tearing down the simulation while worker threads still reference the dispatcher.

Common situations: App shutdown racing with a physics step; disposing the simulation in a scene unload while a job started on another thread is mid-execution.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• Thread count must be positive.
• Trying to lock while another thread owns the lock.
• Trying to unlock while another thread owns the lock.
• The object must be IDisposable, IReferenceable, or IntPtr
• A dispatcher lock must be created from a different thread…

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/f5d6c045bea3d4a2. Report an issue: GitHub.

Appendix: source

Thrown at sources/engine/Stride.BepuPhysics/Stride.BepuPhysics/BepuSimulation.cs:1186

                _workerType = WorkerType.Managed;
                _managedWorker = workerBody;
                SignalThreads(maximumWorkerCount);
                _managedWorker = null;
            }
            else if (maximumWorkerCount == 1)
            {
                workerBody(0);
            }
            _unmanagedContext = null;
            _managedContext = null;
        }

        public void Dispose()
        {
            if (!_disposed)
            {
                if (_managedContext is not null || _unmanagedContext is not null)
                    throw new InvalidOperationException("Cannot dispose while a job is in flight");

                _disposed = true;
                WorkerPools.Dispose();
            }
        }

        private enum WorkerType
        {
            Managed,
            Unmanaged,
        }

        private readonly struct Job(DispatcherWrapper wrapper) : Dispatcher.IBatchJob
        {
            public void Process(int start, int endExclusive)
            {
                for (int i = start; i < endExclusive; i++)
                    wrapper.DispatchThread(i);

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