After upgrade from TYPO3 v9 to v10: Show Pages no longer work (Cannot access protected property)

Question

I have written an extension based on TYPO3 version 9. I have now installed it in a TYPO3 version 10 system and everything seems to work fine. Only the show pages can not be opened anymore.

The error comes:

Cannot access protected property myname\myextension\Domain\Model\Country::$name

I do not understand the mistake. On the list page I use the country name normally. On the Show pages I do not use it at all. So it makes no sense why this should cause problems.

Here is my Show.html

<div class="card">
    <h5 class="card-header" style="text-align: center">
        {house.name}
    </h5>
    <div class="card-body" style="text-align: center">
        <p class="card-text">
            <f:link.external uri="{house.link}" target="_blank">{house.link}</f:link.external>
        </p>
        <h2>Rooms</h2>
        <ul>
            <f:for each="{house.room}" as="room">
                <li>{room.name}</li>
            </f:for>
        </ul>
    </div>
</div>
<f:link.action action="list" class="btn btn-primary">
    BACK
</f:link.action>

My Controller

class HouseController extends \TYPO3\CMS\Extbase\Mvc\Controller\ActionController
{
............
............
    /**
     * @param House $house
     */
    public function showAction(House $house)
    {
        $this->view->assign('house', $house);
    }

As said before the complete code works fine on version 9, there must be some change in version 10 the problems.

Edit: Here is my Country Model

class Country extends \TYPO3\CMS\Extbase\DomainObject\AbstractEntity
{

    /**
     * Country Name
     * 
     * @var string
     * @TYPO3\CMS\Extbase\Annotation\Validate("NotEmpty")
     */
    protected $name = '';

    /**
     * Returns the name
     * 
     * @return string $name
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * Sets the name
     * 
     * @param string $name
     * @return void
     */
    public function setName($name)
    {
        $this->name = $name;
    }
}

And here my House Model (not all lines):

class House extends \TYPO3\CMS\Extbase\DomainObject\AbstractEntity
{
    /**
     * __construct
     */
     public function __construct()
     {

            //Do not remove the next line: It would break the functionality
            $this->initStorageObjects();
     }
    /**
     * Countrie House
     * 
     * @var \myname\myextension\Domain\Model\Country
     * @TYPO3\CMS\Extbase\Annotation\ORM\Lazy
     */
    protected $country = null;

    /**
     * Returns the country
     * 
     * @return \myname\myextension\Domain\Model\Country $country
     */
    public function getCountry()
    {
        return $this->country;
    }

    /**
     * Sets the country
     * 
     * @param \myname\myextension\Domain\Model\Country $country
     * @return void
     */
    public function setCountry(\myname\myextension\Domain\Model\Country $country)
    {
        $this->country = $country;
    }
}

Answer 1

Problem is that you're using @TYPO3\CMS\Extbase\Annotation\ORM\Lazy for a direct relation to a model. The @TYPO3\CMS\Extbase\Annotation\ORM\Lazy annotation is helpful for using it for ObjectStorage, it's not recommended to use for other models directly.