Stock/Model/StockUnitStates.php
static public function isBetterAvailability($stateA, $stateB)
    {
        if ($stateA === $stateB) {
            return false;
        }

        switch ($stateA) {
            // 'pending' is better than 'new' or 'closed'
            case static::STATE_PENDING:
                return in_array($stateB, [static::STATE_NEW, static::STATE_CLOSED], true);
            // 'ready' is better than 'new', 'pending' or 'closed'
            case static::STATE_READY:
                return in_array($stateB, [static::STATE_NEW, static::STATE_PENDING, static::STATE_CLOSED], true);
        }

        return false;
    }
static public function isBetterAvailability($stateA, $stateB)
    {
        if ($stateA === $stateB) {
            return false;
        }

        switch ($stateA) {
            // 'pending' is better than 'new' or 'closed'
            case static::STATE_PENDING:
                return in_array($stateB, [static::STATE_NEW, static::STATE_CLOSED], true);
            // 'ready' is better than 'new', 'pending' or 'closed'
            case static::STATE_READY:
                return in_array($stateB, [static::STATE_NEW, static::STATE_PENDING, static::STATE_CLOSED], true);
        }

        return false;
    }
Returns whether the state A has a better availability than the state B.

@param string $stateA
@param string $stateB

@return bool