ppy/osu · error · InvalidOperationException

Cannot Update a rotate operation without calling Begin first

Error message

Cannot Update a rotate operation without calling Begin first!

What it means

OsuSelectionRotationHandler.Update() applies a rotation delta using originalPositions and originalPathControlPointPositions, which are only populated by Begin(). Without Begin, these fields are null and the Debug.Assert would fire after the exception. The guard throws before reaching the null dereference.

Source

Thrown at osu.Game.Rulesets.Osu/Edit/OsuSelectionRotationHandler.cs:73

            if (OperationInProgress.Value)
                throw new InvalidOperationException($"Cannot {nameof(Begin)} a rotate operation while another is in progress!");

            base.Begin();

            changeHandler?.BeginChange();

            objectsInRotation = selectedMovableObjects.ToArray();
            DefaultOrigin = GeometryUtils.MinimumEnclosingCircle(objectsInRotation).Item1;
            originalPositions = objectsInRotation.ToDictionary(obj => obj, obj => obj.Position);
            originalPathControlPointPositions = objectsInRotation.OfType<IHasPath>().ToDictionary(
                obj => obj,
                obj => obj.Path.ControlPoints.Select(point => point.Position).ToArray());
        }

        public override void Update(float rotation, Vector2? origin = null)
        {
            if (!OperationInProgress.Value)
                throw new InvalidOperationException($"Cannot {nameof(Update)} a rotate operation without calling {nameof(Begin)} first!");

            Debug.Assert(objectsInRotation != null && originalPositions != null && originalPathControlPointPositions != null && DefaultOrigin != null);

            Vector2 actualOrigin = origin ?? DefaultOrigin.Value;

            foreach (var ho in objectsInRotation)
            {
                ho.Position = GeometryUtils.RotatePointAroundOrigin(originalPositions[ho], actualOrigin, rotation);

                if (ho is IHasPath withPath)
                {
                    var originalPath = originalPathControlPointPositions[withPath];

                    for (int i = 0; i < withPath.Path.ControlPoints.Count; ++i)
                        withPath.Path.ControlPoints[i].Position = GeometryUtils.RotatePointAroundOrigin(originalPath[i], Vector2.Zero, rotation);
                }
            }
        }

View on GitHub (pinned to d9c73e12ad)

Solutions

1. Ensure Begin() is called before any Update() in the rotation lifecycle.
2. Guard Update calls behind an OperationInProgress.Value check and ignore deltas when no operation is active.

Example fix

// before
rotationHandler.Update(deltaAngle); // called before Begin

// after
if (rotationHandler.OperationInProgress.Value)
    rotationHandler.Update(deltaAngle);

// Guard Update against calls before Begin
if (rotationHandler.OperationInProgress.Value)
    rotationHandler.Update(deltaAngle, origin);

When it happens

Trigger: Calling Update(rotation, origin) before Begin() has been called — for example, a rotation delta event firing before the operation was started, or the operation state was cleared/reset without restarting.

Common situations: Input event ordering issues where the rotation delta handler runs before initialization; state desync between the UI rotation control and the handler's OperationInProgress; a cancelled operation that nulls the state but the input pipeline still delivers Update.

Related errors

• Cannot Begin a rotate operation while another is in progress
• Cannot Commit a rotate operation without calling Begin first
• Cannot Begin a scale operation while another is in progress!
• Cannot Update a scale operation without calling Begin first!
• Cannot Commit a rotate operation without calling Begin first

AI-assisted analysis of ppy/osu@d9c73e12ad (2026-08-13). Data as JSON: /api/errors/371be55429868085. Report an issue: GitHub.