What causes "This operation is already in progress" in stride3d/stride?

Avoid re-entrant Rollback/Rollforward calls from within rollback handlers

stride3d/stride · error · TransactionException

This operation is already in progress

Error message

This operation is already in progress

What it means

Reentrancy guard in Operation.Rollback: the operation is already mid-rollback (the inProgress flag is set), meaning Rollback was called recursively or concurrently on the same operation. Transaction operations are not reentrant to keep undo state consistent.

Solutions

Avoid re-entrant Rollback/Rollforward calls from within rollback handlers
Serialize access to the operation with a lock if used from multiple threads
Wait for the in-progress operation to finish before issuing another one

Example fix

// before (re-entrant from handler)
void OnOperationEvent() => operation.Rollback(); // may recurse
// after
lock (operationLock)
{
    if (!inRollback) operation.Rollback();
}

Defensive patterns

Strategy: retry

Validate before calling

lock (operationLock)
{
    if (operationInProgress) return; // or queue the request
}

Type guard

bool IsOperationIdle(Operation o) => !o.IsFrozen; // plus external in-progress tracking

Try / catch

try { operation.Rollback(); }
catch (TransactionException ex) when (ex.Message == "This operation is already in progress")
{
    // retry after the current rollback finishes, or queue
}

Prevention

Never call Rollback re-entrantly from rollback event handlers
Synchronize multi-threaded operation access with a lock
Queue undo requests instead of issuing them concurrently

When it happens

Trigger: Calling IOperation.Rollback() recursively or concurrently while a prior Rollback()/Rollforward() call on the same operation has not returned — typically via re-entrancy from events raised during rollback.

Common situations: Rollback handlers that re-enter the transaction API, multi-threaded access to a shared operation without synchronization.

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

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/897983406dab12e7. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.Design/Transactions/Operation.cs:84

    }

    /// <inheritdoc/>
    void IOperation.Freeze()
    {
        if (IsFrozen)
            throw new TransactionException("This operation is already frozen.");

        FreezeContent();
        IsFrozen = true;
    }

    /// <inheritdoc/>
    void IOperation.Rollback()
    {
        if (IsFrozen)
            throw new TransactionException("A disposed operation cannot be rollbacked.");
        if (inProgress)
            throw new TransactionException("This operation is already in progress");

        inProgress = true;
        Rollback();
        inProgress = false;
    }

    /// <inheritdoc/>
    void IOperation.Rollforward()
    {
        if (IsFrozen)
            throw new TransactionException("A disposed operation cannot be rollforwarded.");
        if (inProgress)
            throw new TransactionException("This operation is already in progress");

        inProgress = true;
        Rollforward();
        inProgress = false;
    }

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