grafana/k6 · error

mouse move: %w

Error message

mouse move: %w

What it means

Root-level error from the internal Mouse.move(): an individual CDP Input.dispatchMouseEvent(mouseMoved) call failed during the interpolation loop. It is a raw Chrome DevTools Protocol failure: the session or target disappeared (page closed, browser crashed, websocket dropped), not a problem with the coordinates.

Source

Thrown at internal/js/modules/k6/browser/common/mouse.go:138

	if err := m.move(x, y, opts); err != nil {
		return fmt.Errorf("moving the mouse pointer to x:%f y:%f: %w", x, y, err)
	}
	return nil
}

func (m *Mouse) move(x float64, y float64, opts *MouseMoveOptions) error {
	fromX := m.x
	fromY := m.y
	m.x = x
	m.y = y
	for i := int64(1); i <= opts.Steps; i++ {
		x := fromX + (m.x-fromX)*float64(i/opts.Steps)
		y := fromY + (m.y-fromY)*float64(i/opts.Steps)
		action := input.DispatchMouseEvent(input.MouseMoved, x, y).
			WithButton(m.button).
			WithModifiers(input.Modifier(m.keyboard.modifiers))
		if err := action.Do(cdp.WithExecutor(m.ctx, m.session)); err != nil {
			return fmt.Errorf("mouse move: %w", err)
		}
	}

	return nil
}

View on GitHub (pinned to 93accf6570)

Solutions

1. Check that Chromium is alive and not OOM-killed (container logs, dmesg)
2. Guard the gesture: verify the page is open immediately before the move
3. Restart the full gesture on a freshly created page; mouse position is lost with the session
4. Reduce steps count to shrink the failure window

Example fix

// before
await page.mouse.move(800, 600, { steps: 40 });

// after
if (page.isClosed()) throw new Error('page closed before mouse.move');
await page.mouse.move(800, 600, { steps: 10 });

if (page.isClosed()) throw new Error('page closed');
await page.mouse.move(x, y, { steps: 5 });

try {
  await page.mouse.move(x, y, { steps: 5 });
} catch (e) {
  // raw CDP mouseMoved failure == session/target loss
  if (/target closed|connection/i.test(e.message)) {
    throw new Error('browser session lost during mouse move');
  }
  throw e;
}

When it happens

Trigger: action.Do(cdp.WithExecutor(...)) for mouseMoved returning an error on any step: target destroyed, DevTools websocket closed, browser process crash or OOM kill mid-gesture.

Common situations: Chromium killed under memory pressure during long drag simulations; page closed while a multi-step move was in flight; flaky remote CDP connection; continuing after an earlier unhandled error left the session dead.

Related errors

• mouse down: %w
• mouse up: %w
• evaluating pointer action: %w
• run if waiting for debugger to attach: %w
• internal error while enabling %T: %w

AI-assisted analysis of grafana/k6@93accf6570 (2026-08-15). Data as JSON: /api/errors/d93b4fb59dbc5556. Report an issue: GitHub.