stride3d/stride · error · InvalidOperationException

SDL GameController already opened

Error message

SDL GameController already opened {deviceIndex}/{*(Guid*)&joystickId}/{joystickName}

What it means

InputSourceSDL.OpenDevice tracks already-open joysticks by joystick instance id in joystickInstanceIdToDeviceId. If OpenDevice is called for a device whose instance id is already mapped, it throws InvalidOperationException with the device index, GUID and name. Opening the same SDL game controller twice would create duplicate device objects for one physical device.

Solutions

Check joystickInstanceIdToDeviceId before calling OpenDevice and skip if the instance id is already present
Ensure device-removed handling runs so stale instance ids are cleaned before re-open
Debounce SDL controller added/removed events before opening
Log the device index/GUID from the message to identify the duplicated device and its source of double-open

Example fix

// before
OpenDevice(deviceIndex); // may already be open
// after
if (!joystickInstanceIdToDeviceId.ContainsKey(GetJoystickInstanceId(deviceIndex)))
    OpenDevice(deviceIndex);

Defensive patterns

Strategy: validation

Validate before calling

if (!joystickInstanceIdToDeviceId.ContainsKey(GetJoystickInstanceId(deviceIndex)))
    OpenDevice(deviceIndex);

Try / catch

try { sourceOpenDevice(deviceIndex); } catch (InvalidOperationException) { /* already open, ignore */ }

Prevention

Process SDL joystick added events idempotently
Ensure removal handling clears instance-id mappings before the same id can be reopened
Debounce rapid connect/disconnect events from the OS

When it happens

Trigger: SDL raising a device-added event twice for the same instance id (e.g. Connect/Disconnect events coalesced or replayed), or calling OpenDevice manually for an index that was already opened.

Common situations: SDL joystick hot-plug storms on some platforms/drivers; re-scanning device lists without clearing state; driver quirks where unplug/replug reuses the same instance id before cleanup ran.

Understand the failure class

Background: "already exists" / EEXIST / FileAlreadyExistsException: what the 'file already exists' error means and how to fix it — this error's family across 37 libraries.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/c537a9809dec768f. Report an issue: GitHub.

Appendix: source

Thrown at sources/engine/Stride.Input/SDL/InputSourceSDL.cs:102

        }

        public override void Scan()
        {
            for (int i = 0; i < SDL.NumJoysticks(); i++)
            { 
                if (!joystickInstanceIdToDeviceId.ContainsKey(GetJoystickInstanceId(i)))
                {
                    OpenDevice(i);
                }
            }
        }

        private void OpenDevice(int deviceIndex)
        {
            var joystickId = SDL.JoystickGetDeviceGUID(deviceIndex);
            var joystickName = SDL.JoystickNameForIndexS(deviceIndex);
            if (joystickInstanceIdToDeviceId.ContainsKey(GetJoystickInstanceId(deviceIndex)))
                throw new InvalidOperationException($"SDL GameController already opened {deviceIndex}/{*(Guid*)&joystickId}/{joystickName}");

            var controller = new GameControllerSDL(this, deviceIndex);

            IInputDevice resultingDevice = controller;

            // Find gamepad layout
            var layout = GamePadLayouts.FindLayout(this, controller);
            if (layout != null)
            {
                // Create a gamepad wrapping around the controller
                var gamePad = new GamePadSDL(this, inputManager, controller, layout);
                resultingDevice = gamePad; // Register gamepad instead
            }

            controller.Disconnected += (sender, args) =>
            {
                // Queue device for removal
                devicesToRemove.Add(resultingDevice.Id);

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