Deprecation: #110347 - LazyLoadingProxy and LazyObjectStorage 

Description 

The internal Extbase lazy loading classes

• \TYPO3\CMS\Extbase\Persistence\Generic\LazyLoadingProxy
• \TYPO3\CMS\Extbase\Persistence\Generic\LazyObjectStorage
• \TYPO3\CMS\Extbase\Persistence\Generic\LoadingStrategyInterface

have been marked as deprecated. Lazy relations of domain model properties annotated with #[Extbase\ORM\Lazy] are created as native PHP lazy objects by the DataMapper instead: 1:n and m:n relations as lazy ghost instances of \TYPO3\CMS\Extbase\Persistence\ObjectStorage , 1:1 and n:1 relations as lazy proxy instances of the actual target entity class.

Impact 

Instantiating LazyLoadingProxy or LazyObjectStorage will trigger a PHP E_USER_DEPRECATED error. All three classes will be removed in TYPO3 v16.0.

TYPO3 Core does not create instances of these classes anymore. Existing instanceof checks against them evaluate to false for relations created by the DataMapper.

Affected installations 

Installations with extensions that reference these classes, for example in union type declarations of lazy model properties, in instanceof checks, or by calling LazyLoadingProxy->_loadRealInstance() .

The extension scanner reports usages as a strong match.

Migration 

No change is required for declaring lazy relations, the #[Extbase\ORM\Lazy] attribute remains the single way to do so.

Union type declarations can be reduced to the actual entity type:

// Before
#[Extbase\ORM\Lazy]
protected Category|LazyLoadingProxy|null $parent = null;

// After
#[Extbase\ORM\Lazy]
protected ?Category $parent = null;

Calls to _loadRealInstance() can be removed altogether, since the property value is an instance of the target entity class in all cases and initializes itself transparently on first access:

// Before
public function getParent(): ?Category
{
    if ($this->parent instanceof LazyLoadingProxy) {
        $this->parent->_loadRealInstance();
    }
    return $this->parent;
}

// After
public function getParent(): ?Category
{
    return $this->parent;
}

Code that needs to know whether a lazy object has been initialized (for example to avoid triggering database queries) can use native PHP reflection:

$reflection = new \ReflectionClass(ObjectStorage::class);
if ($reflection->isUninitializedLazyObject($storage)) {
    // storage content has not been fetched from the database yet
}