TYPO3 Exception 1234386924

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TYPO3 13.5.9, 2025-05-12 Cannot create empty instance of the class "ObjectStorage"...

Warning

(1/1) #1234386924 TYPO3CMSExtbasePersistenceGenericExceptionInvalidClassException Cannot create empty instance of the class "TYPO3CMSExtbasePersistenceObjectStorage" because it does not implement the TYPO3CMSExtbaseDomainObjectDomainObjectInterface.

in /var/www/html/vendor/typo3/cms-extbase/Classes/Persistence/Generic/Mapper/DataMapper.php line 175

Happened when in an Extbase Model (AbstractEntity) the object Storage was missing information about the type of objects to be saved.

Saved like this:

 class Theme extends AbstractEntity
 {
   protected string $name = '';
+  /** @var ?ObjectStorage<InfoCenter>  */
   protected ?ObjectStorage $infoCenter = null;

Error-messages:

#1234386924: Cannot create empty instance of the class "TYPO3CMSExtbaseDomainRepositoryFrontendUserRepository" because it does not implement the TYPO3CMSExtbaseDomainObjectDomainObjectInterface.
#1234386924: Cannot create empty instance of the class "TYPO3CMSExtbasePersistenceObjectStorage" because it does not implement the TYPO3CMSExtbaseDomainObjectDomainObjectInterface.

Fix

Assure that all classes in your model files are defined and annotated correctly.

Below is an example for one property of another table:

/**
  * contact
  *
  * @var \Vendor\Extension\Domain\Model\Contact
  */
 protected $contact = NULL;


 /**
  * Returns the contact
  *
  * @return \Vendor\Extension\Domain\Model\Contact $contact
  */
 public function getContact() {
     return $this->contact;
 }

 /**
  * Sets the contact
  *
  * @param \Vendor\Extension\Domain\Model\Contact $contact
  * @return void
  */
 public function setContact(\Vendor\Extension\Domain\Model\Contact $contact) {
     $this->contact = $contact;
 }

A more complicated example is when records or files are handled by ObjectStorage, this is an Object where several items can be stored and items can be added and removed from a stack:

/**
 * member
 *
 * @var \TYPO3\CMS\Extbase\Persistence\ObjectStorage<\Vendor\Extension\Domain\Model\Member>
 */
 protected $member = NULL;

/**
 * __construct
 */
public function __construct() {
    //Do not remove the next line: It would break the functionality
    $this->initStorageObjects();
}

/**
 * Initializes all ObjectStorage properties
 * Do not modify this method!
 * It will be rewritten on each save in the extension builder
 * You may modify the constructor of this class instead
 *
 * @return void
 */
protected function initStorageObjects() {
    $this->member = new \TYPO3\CMS\Extbase\Persistence\ObjectStorage();
}

/**
 * Adds a member
 *
 * @param \Vendor\Extension\Domain\Model\Member $member
 * @return void
 */
public function addMember(\Vendor\Extension\Domain\Model\Member $member) {
    $this->member->attach($member);
}

/**
 * Removes a member
 *
 * @param $memberToRemove The member to be removed
 * @return void
 */
public function removeMember(\Vendor\Extension\Domain\Model\Member $memberToRemove) {
    $this->member->detach($memberToRemove);
}

/**
 * Returns the member
 *
 * @return \TYPO3\CMS\Extbase\Persistence\ObjectStorage<\Vendor\Extension\Domain\Model\Member> $member
 */
public function getMember() {
    return $this->member;
}

/**
 * Sets the member
 *
 * @param \TYPO3\CMS\Extbase\Persistence\ObjectStorage<\Vendor\Extension\Domain\Model\Member> $member
 * @return void
 */
public function setMember(\TYPO3\CMS\Extbase\Persistence\ObjectStorage $member) {
    $this->member = $member;
}