Common/EventListener/AbstractAdjustmentListener.php
public function onPreDelete(ResourceEventInterface $event)
    {
        $this->throwIllegalOperationIfAdjustmentIsImmutable($event);

        $adjustment = $this->getAdjustmentFromEvent($event);

        // Pre load adjustments collection
        if (null === $adjustable = $adjustment->getAdjustable()) {
            return;
        }

        $adjustable->getAdjustments()->toArray();
    }
public function onPreDelete(ResourceEventInterface $event)
    {
        $this->throwIllegalOperationIfAdjustmentIsImmutable($event);

        $adjustment = $this->getAdjustmentFromEvent($event);

        // Pre load adjustments collection
        if (null === $adjustable = $adjustment->getAdjustable()) {
            return;
        }

        $adjustable->getAdjustments()->toArray();
    }
Pre delete event handler.

@param ResourceEventInterface $event

@throws IllegalOperationException