/lib/Doctrine/ORM/UnitOfWork.php

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<?php

declare(strict_types=1);

namespace Doctrine\ORM;

use DateTimeInterface;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\Common\EventManager;
use Doctrine\Common\Proxy\Proxy;
use Doctrine\DBAL\LockMode;
use Doctrine\Deprecations\Deprecation;
use Doctrine\ORM\Cache\Persister\CachedPersister;
use Doctrine\ORM\Event\LifecycleEventArgs;
use Doctrine\ORM\Event\ListenersInvoker;
use Doctrine\ORM\Event\OnFlushEventArgs;
use Doctrine\ORM\Event\PostFlushEventArgs;
use Doctrine\ORM\Event\PreFlushEventArgs;
use Doctrine\ORM\Event\PreUpdateEventArgs;
use Doctrine\ORM\Exception\UnexpectedAssociationValue;
use Doctrine\ORM\Id\AssignedGenerator;
use Doctrine\ORM\Internal\CommitOrderCalculator;
use Doctrine\ORM\Internal\HydrationCompleteHandler;
use Doctrine\ORM\Mapping\ClassMetadata;
use Doctrine\ORM\Mapping\MappingException;
use Doctrine\ORM\Mapping\Reflection\ReflectionPropertiesGetter;
use Doctrine\ORM\Persisters\Collection\CollectionPersister;
use Doctrine\ORM\Persisters\Collection\ManyToManyPersister;
use Doctrine\ORM\Persisters\Collection\OneToManyPersister;
use Doctrine\ORM\Persisters\Entity\BasicEntityPersister;
use Doctrine\ORM\Persisters\Entity\EntityPersister;
use Doctrine\ORM\Persisters\Entity\JoinedSubclassPersister;
use Doctrine\ORM\Persisters\Entity\SingleTablePersister;
use Doctrine\ORM\Utility\IdentifierFlattener;
use Doctrine\Persistence\Mapping\RuntimeReflectionService;
use Doctrine\Persistence\NotifyPropertyChanged;
use Doctrine\Persistence\ObjectManagerAware;
use Doctrine\Persistence\PropertyChangedListener;
use Exception;
use InvalidArgumentException;
use RuntimeException;
use Throwable;
use UnexpectedValueException;

use function array_combine;
use function array_diff_key;
use function array_filter;
use function array_key_exists;
use function array_map;
use function array_merge;
use function array_pop;
use function array_sum;
use function array_values;
use function count;
use function current;
use function get_class;
use function implode;
use function in_array;
use function is_array;
use function is_object;
use function method_exists;
use function reset;
use function spl_object_id;
use function sprintf;

/**
 * The UnitOfWork is responsible for tracking changes to objects during an
 * "object-level" transaction and for writing out changes to the database
 * in the correct order.
 *
 * Internal note: This class contains highly performance-sensitive code.
 */
class UnitOfWork implements PropertyChangedListener
{
    /**
     * An entity is in MANAGED state when its persistence is managed by an EntityManager.
     */
    public const STATE_MANAGED = 1;

    /**
     * An entity is new if it has just been instantiated (i.e. using the "new" operator)
     * and is not (yet) managed by an EntityManager.
     */
    public const STATE_NEW = 2;

    /**
     * A detached entity is an instance with persistent state and identity that is not
     * (or no longer) associated with an EntityManager (and a UnitOfWork).
     */
    public const STATE_DETACHED = 3;

    /**
     * A removed entity instance is an instance with a persistent identity,
     * associated with an EntityManager, whose persistent state will be deleted
     * on commit.
     */
    public const STATE_REMOVED = 4;

    /**
     * Hint used to collect all primary keys of associated entities during hydration
     * and execute it in a dedicated query afterwards
     *
     * @see https://www.doctrine-project.org/projects/doctrine-orm/en/latest/reference/dql-doctrine-query-language.html#temporarily-change-fetch-mode-in-dql
     */
    public const HINT_DEFEREAGERLOAD = 'deferEagerLoad';

    /**
     * The identity map that holds references to all managed entities that have
     * an identity. The entities are grouped by their class name.
     * Since all classes in a hierarchy must share the same identifier set,
     * we always take the root class name of the hierarchy.
     *
     * @var mixed[]
     * @psalm-var array<class-string, array<string, object|null>>
     */
    private $identityMap = [];

    /**
     * Map of all identifiers of managed entities.
     * Keys are object ids (spl_object_id).
     *
     * @var mixed[]
     * @psalm-var array<int, array<string, mixed>>
     */
    private $entityIdentifiers = [];

    /**
     * Map of the original entity data of managed entities.
     * Keys are object ids (spl_object_id). This is used for calculating changesets
     * at commit time.
     *
     * Internal note: Note that PHPs "copy-on-write" behavior helps a lot with memory usage.
     *                A value will only really be copied if the value in the entity is modified
     *                by the user.
     *
     * @psalm-var array<int, array<string, mixed>>
     */
    private $originalEntityData = [];

    /**
     * Map of entity changes. Keys are object ids (spl_object_id).
     * Filled at the beginning of a commit of the UnitOfWork and cleaned at the end.
     *
     * @psalm-var array<int, array<string, array{mixed, mixed}>>
     */
    private $entityChangeSets = [];

    /**
     * The (cached) states of any known entities.
     * Keys are object ids (spl_object_id).
     *
     * @psalm-var array<int, self::STATE_*>
     */
    private $entityStates = [];

    /**
     * Map of entities that are scheduled for dirty checking at commit time.
     * This is only used for entities with a change tracking policy of DEFERRED_EXPLICIT.
     * Keys are object ids (spl_object_id).
     *
     * @psalm-var array<class-string, array<int, mixed>>
     */
    private $scheduledForSynchronization = [];

    /**
     * A list of all pending entity insertions.
     *
     * @psalm-var array<int, object>
     */
    private $entityInsertions = [];

    /**
     * A list of all pending entity updates.
     *
     * @psalm-var array<int, object>
     */
    private $entityUpdates = [];

    /**
     * Any pending extra updates that have been scheduled by persisters.
     *
     * @psalm-var array<int, array{object, array<string, array{mixed, mixed}>}>
     */
    private $extraUpdates = [];

    /**
     * A list of all pending entity deletions.
     *
     * @psalm-var array<int, object>
     */
    private $entityDeletions = [];

    /**
     * New entities that were discovered through relationships that were not
     * marked as cascade-persist. During flush, this array is populated and
     * then pruned of any entities that were discovered through a valid
     * cascade-persist path. (Leftovers cause an error.)
     *
     * Keys are OIDs, payload is a two-item array describing the association
     * and the entity.
     *
     * @var object[][]|array[][] indexed by respective object spl_object_id()
     */
    private $nonCascadedNewDetectedEntities = [];

    /**
     * All pending collection deletions.
     *
     * @psalm-var array<int, Collection<array-key, object>>
     */
    private $collectionDeletions = [];

    /**
     * All pending collection updates.
     *
     * @psalm-var array<int, Collection<array-key, object>>
     */
    private $collectionUpdates = [];

    /**
     * List of collections visited during changeset calculation on a commit-phase of a UnitOfWork.
     * At the end of the UnitOfWork all these collections will make new snapshots
     * of their data.
     *
     * @psalm-var array<int, Collection<array-key, object>>
     */
    private $visitedCollections = [];

    /**
     * The EntityManager that "owns" this UnitOfWork instance.
     *
     * @var EntityManagerInterface
     */
    private $em;

    /**
     * The entity persister instances used to persist entity instances.
     *
     * @psalm-var array<string, EntityPersister>
     */
    private $persisters = [];

    /**
     * The collection persister instances used to persist collections.
     *
     * @psalm-var array<string, CollectionPersister>
     */
    private $collectionPersisters = [];

    /**
     * The EventManager used for dispatching events.
     *
     * @var EventManager
     */
    private $evm;

    /**
     * The ListenersInvoker used for dispatching events.
     *
     * @var ListenersInvoker
     */
    private $listenersInvoker;

    /**
     * The IdentifierFlattener used for manipulating identifiers
     *
     * @var IdentifierFlattener
     */
    private $identifierFlattener;

    /**
     * Orphaned entities that are scheduled for removal.
     *
     * @psalm-var array<int, object>
     */
    private $orphanRemovals = [];

    /**
     * Read-Only objects are never evaluated
     *
     * @var array<int, true>
     */
    private $readOnlyObjects = [];

    /**
     * Map of Entity Class-Names and corresponding IDs that should eager loaded when requested.
     *
     * @psalm-var array<class-string, array<string, mixed>>
     */
    private $eagerLoadingEntities = [];

    /** @var bool */
    protected $hasCache = false;

    /**
     * Helper for handling completion of hydration
     *
     * @var HydrationCompleteHandler
     */
    private $hydrationCompleteHandler;

    /** @var ReflectionPropertiesGetter */
    private $reflectionPropertiesGetter;

    /**
     * Initializes a new UnitOfWork instance, bound to the given EntityManager.
     */
    public function __construct(EntityManagerInterface $em)
    {
        $this->em                         = $em;
        $this->evm                        = $em->getEventManager();
        $this->listenersInvoker           = new ListenersInvoker($em);
        $this->hasCache                   = $em->getConfiguration()->isSecondLevelCacheEnabled();
        $this->identifierFlattener        = new IdentifierFlattener($this, $em->getMetadataFactory());
        $this->hydrationCompleteHandler   = new HydrationCompleteHandler($this->listenersInvoker, $em);
        $this->reflectionPropertiesGetter = new ReflectionPropertiesGetter(new RuntimeReflectionService());
    }

    /**
     * Commits the UnitOfWork, executing all operations that have been postponed
     * up to this point. The state of all managed entities will be synchronized with
     * the database.
     *
     * The operations are executed in the following order:
     *
     * 1) All entity insertions
     * 2) All entity updates
     * 3) All collection deletions
     * 4) All collection updates
     * 5) All entity deletions
     *
     * @param object|mixed[]|null $entity
     *
     * @return void
     *
     * @throws Exception
     */
    public function commit($entity = null)
    {
        // Raise preFlush
        if ($this->evm->hasListeners(Events::preFlush)) {
            $this->evm->dispatchEvent(Events::preFlush, new PreFlushEventArgs($this->em));
        }

        // Compute changes done since last commit.
        if ($entity === null) {
            $this->computeChangeSets();
        } elseif (is_object($entity)) {
            $this->computeSingleEntityChangeSet($entity);
        } elseif (is_array($entity)) {
            foreach ($entity as $object) {
                $this->computeSingleEntityChangeSet($object);
            }
        }

        if (
            ! ($this->entityInsertions ||
                $this->entityDeletions ||
                $this->entityUpdates ||
                $this->collectionUpdates ||
                $this->collectionDeletions ||
                $this->orphanRemovals)
        ) {
            $this->dispatchOnFlushEvent();
            $this->dispatchPostFlushEvent();

            $this->postCommitCleanup($entity);

            return; // Nothing to do.
        }

        $this->assertThatThereAreNoUnintentionallyNonPersistedAssociations();

        if ($this->orphanRemovals) {
            foreach ($this->orphanRemovals as $orphan) {
                $this->remove($orphan);
            }
        }

        $this->dispatchOnFlushEvent();

        // Now we need a commit order to maintain referential integrity
        $commitOrder = $this->getCommitOrder();

        $conn = $this->em->getConnection();
        $conn->beginTransaction();

        try {
            // Collection deletions (deletions of complete collections)
            foreach ($this->collectionDeletions as $collectionToDelete) {
                if (! $collectionToDelete instanceof PersistentCollection) {
                    $this->getCollectionPersister($collectionToDelete->getMapping())->delete($collectionToDelete);

                    continue;
                }

                // Deferred explicit tracked collections can be removed only when owning relation was persisted
                $owner = $collectionToDelete->getOwner();

                if ($this->em->getClassMetadata(get_class($owner))->isChangeTrackingDeferredImplicit() || $this->isScheduledForDirtyCheck($owner)) {
                    $this->getCollectionPersister($collectionToDelete->getMapping())->delete($collectionToDelete);
                }
            }

            if ($this->entityInsertions) {
                foreach ($commitOrder as $class) {
                    $this->executeInserts($class);
                }
            }

            if ($this->entityUpdates) {
                foreach ($commitOrder as $class) {
                    $this->executeUpdates($class);
                }
            }

            // Extra updates that were requested by persisters.
            if ($this->extraUpdates) {
                $this->executeExtraUpdates();
            }

            // Collection updates (deleteRows, updateRows, insertRows)
            foreach ($this->collectionUpdates as $collectionToUpdate) {
                $this->getCollectionPersister($collectionToUpdate->getMapping())->update($collectionToUpdate);
            }

            // Entity deletions come last and need to be in reverse commit order
            if ($this->entityDeletions) {
                for ($count = count($commitOrder), $i = $count - 1; $i >= 0 && $this->entityDeletions; --$i) {
                    $this->executeDeletions($commitOrder[$i]);
                }
            }

            // Commit failed silently
            if ($conn->commit() === false) {
                $object = is_object($entity) ? $entity : null;

                throw new OptimisticLockException('Commit failed', $object);
            }
        } catch (Throwable $e) {
            $this->em->close();

            if ($conn->isTransactionActive()) {
                $conn->rollBack();
            }

            $this->afterTransactionRolledBack();

            throw $e;
        }

        $this->afterTransactionComplete();

        // Take new snapshots from visited collections
        foreach ($this->visitedCollections as $coll) {
            $coll->takeSnapshot();
        }

        $this->dispatchPostFlushEvent();

        $this->postCommitCleanup($entity);
    }

    /**
     * @param object|object[]|null $entity
     */
    private function postCommitCleanup($entity): void
    {
        $this->entityInsertions               =
        $this->entityUpdates                  =
        $this->entityDeletions                =
        $this->extraUpdates                   =
        $this->collectionUpdates              =
        $this->nonCascadedNewDetectedEntities =
        $this->collectionDeletions            =
        $this->visitedCollections             =
        $this->orphanRemovals                 = [];

        if ($entity === null) {
            $this->entityChangeSets = $this->scheduledForSynchronization = [];

            return;
        }

        $entities = is_object($entity)
            ? [$entity]
            : $entity;

        foreach ($entities as $object) {
            $oid = spl_object_id($object);

            $this->clearEntityChangeSet($oid);

            unset($this->scheduledForSynchronization[$this->em->getClassMetadata(get_class($object))->rootEntityName][$oid]);
        }
    }

    /**
     * Computes the changesets of all entities scheduled for insertion.
     */
    private function computeScheduleInsertsChangeSets(): void
    {
        foreach ($this->entityInsertions as $entity) {
            $class = $this->em->getClassMetadata(get_class($entity));

            $this->computeChangeSet($class, $entity);
        }
    }

    /**
     * Only flushes the given entity according to a ruleset that keeps the UoW consistent.
     *
     * 1. All entities scheduled for insertion, (orphan) removals and changes in collections are processed as well!
     * 2. Read Only entities are skipped.
     * 3. Proxies are skipped.
     * 4. Only if entity is properly managed.
     *
     * @param object $entity
     *
     * @throws InvalidArgumentException
     */
    private function computeSingleEntityChangeSet($entity): void
    {
        $state = $this->getEntityState($entity);

        if ($state !== self::STATE_MANAGED && $state !== self::STATE_REMOVED) {
            throw new InvalidArgumentException('Entity has to be managed or scheduled for removal for single computation ' . self::objToStr($entity));
        }

        $class = $this->em->getClassMetadata(get_class($entity));

        if ($state === self::STATE_MANAGED && $class->isChangeTrackingDeferredImplicit()) {
            $this->persist($entity);
        }

        // Compute changes for INSERTed entities first. This must always happen even in this case.
        $this->computeScheduleInsertsChangeSets();

        if ($class->isReadOnly) {
            return;
        }

        // Ignore uninitialized proxy objects
        if ($entity instanceof Proxy && ! $entity->__isInitialized()) {
            return;
        }

        // Only MANAGED entities that are NOT SCHEDULED FOR INSERTION OR DELETION are processed here.
        $oid = spl_object_id($entity);

        if (! isset($this->entityInsertions[$oid]) && ! isset($this->entityDeletions[$oid]) && isset($this->entityStates[$oid])) {
            $this->computeChangeSet($class, $entity);
        }
    }

    /**
     * Executes any extra updates that have been scheduled.
     */
    private function executeExtraUpdates(): void
    {
        foreach ($this->extraUpdates as $oid => $update) {
            [$entity, $changeset] = $update;

            $this->entityChangeSets[$oid] = $changeset;
            $this->getEntityPersister(get_class($entity))->update($entity);
        }

        $this->extraUpdates = [];
    }

    /**
     * Gets the changeset for an entity.
     *
     * @param object $entity
     *
     * @return mixed[][]
     * @psalm-return array<string, array{mixed, mixed}|PersistentCollection>
     */
    public function & getEntityChangeSet($entity)
    {
        $oid  = spl_object_id($entity);
        $data = [];

        if (! isset($this->entityChangeSets[$oid])) {
            return $data;
        }

        return $this->entityChangeSets[$oid];
    }

    /**
     * Computes the changes that happened to a single entity.
     *
     * Modifies/populates the following properties:
     *
     * {@link _originalEntityData}
     * If the entity is NEW or MANAGED but not yet fully persisted (only has an id)
     * then it was not fetched from the database and therefore we have no original
     * entity data yet. All of the current entity data is stored as the original entity data.
     *
     * {@link _entityChangeSets}
     * The changes detected on all properties of the entity are stored there.
     * A change is a tuple array where the first entry is the old value and the second
     * entry is the new value of the property. Changesets are used by persisters
     * to INSERT/UPDATE the persistent entity state.
     *
     * {@link _entityUpdates}
     * If the entity is already fully MANAGED (has been fetched from the database before)
     * and any changes to its properties are detected, then a reference to the entity is stored
     * there to mark it for an update.
     *
     * {@link _collectionDeletions}
     * If a PersistentCollection has been de-referenced in a fully MANAGED entity,
     * then this collection is marked for deletion.
     *
     * @param ClassMetadata $class  The class descriptor of the entity.
     * @param object        $entity The entity for which to compute the changes.
     * @psalm-param ClassMetadata<T> $class
     * @psalm-param T $entity
     *
     * @return void
     *
     * @template T of object
     *
     * @ignore
     */
    public function computeChangeSet(ClassMetadata $class, $entity)
    {
        $oid = spl_object_id($entity);

        if (isset($this->readOnlyObjects[$oid])) {
            return;
        }

        if (! $class->isInheritanceTypeNone()) {
            $class = $this->em->getClassMetadata(get_class($entity));
        }

        $invoke = $this->listenersInvoker->getSubscribedSystems($class, Events::preFlush) & ~ListenersInvoker::INVOKE_MANAGER;

        if ($invoke !== ListenersInvoker::INVOKE_NONE) {
            $this->listenersInvoker->invoke($class, Events::preFlush, $entity, new PreFlushEventArgs($this->em), $invoke);
        }

        $actualData = [];

        foreach ($class->reflFields as $name => $refProp) {
            $value = $refProp->getValue($entity);

            if ($class->isCollectionValuedAssociation($name) && $value !== null) {
                if ($value instanceof PersistentCollection) {
                    if ($value->getOwner() === $entity) {
                        continue;
                    }

                    $value = new ArrayCollection($value->getValues());
                }

                // If $value is not a Collection then use an ArrayCollection.
                if (! $value instanceof Collection) {
                    $value = new ArrayCollection($value);
                }

                $assoc = $class->associationMappings[$name];

                // Inject PersistentCollection
                $value = new PersistentCollection(
                    $this->em,
                    $this->em->getClassMetadata($assoc['targetEntity']),
                    $value
                );
                $value->setOwner($entity, $assoc);
                $value->setDirty(! $value->isEmpty());

                $class->reflFields[$name]->setValue($entity, $value);

                $actualData[$name] = $value;

                continue;
            }

            if (( ! $class->isIdentifier($name) || ! $class->isIdGeneratorIdentity()) && ($name !== $class->versionField)) {
                $actualData[$name] = $value;
            }
        }

        if (! isset($this->originalEntityData[$oid])) {
            // Entity is either NEW or MANAGED but not yet fully persisted (only has an id).
            // These result in an INSERT.
            $this->originalEntityData[$oid] = $actualData;
            $changeSet                      = [];

            foreach ($actualData as $propName => $actualValue) {
                if (! isset($class->associationMappings[$propName])) {
                    $changeSet[$propName] = [null, $actualValue];

                    continue;
                }

                $assoc = $class->associationMappings[$propName];

                if ($assoc['isOwningSide'] && $assoc['type'] & ClassMetadata::TO_ONE) {
                    $changeSet[$propName] = [null, $actualValue];
                }
            }

            $this->entityChangeSets[$oid] = $changeSet;
        } else {
            // Entity is "fully" MANAGED: it was already fully persisted before
            // and we have a copy of the original data
            $originalData           = $this->originalEntityData[$oid];
            $isChangeTrackingNotify = $class->isChangeTrackingNotify();
            $changeSet              = $isChangeTrackingNotify && isset($this->entityChangeSets[$oid])
                ? $this->entityChangeSets[$oid]
                : [];

            foreach ($actualData as $propName => $actualValue) {
                // skip field, its a partially omitted one!
                if (! (isset($originalData[$propName]) || array_key_exists($propName, $originalData))) {
                    continue;
                }

                $orgValue = $originalData[$propName];

                // skip if value haven't changed
                if ($orgValue === $actualValue) {
                    continue;
                }

                // if regular field
                if (! isset($class->associationMappings[$propName])) {
                    if ($isChangeTrackingNotify) {
                        continue;
                    }

                    $changeSet[$propName] = [$orgValue, $actualValue];

                    continue;
                }

                $assoc = $class->associationMappings[$propName];

                // Persistent collection was exchanged with the "originally"
                // created one. This can only mean it was cloned and replaced
                // on another entity.
                if ($actualValue instanceof PersistentCollection) {
                    $owner = $actualValue->getOwner();
                    if ($owner === null) { // cloned
                        $actualValue->setOwner($entity, $assoc);
                    } elseif ($owner !== $entity) { // no clone, we have to fix
                        if (! $actualValue->isInitialized()) {
                            $actualValue->initialize(); // we have to do this otherwise the cols share state
                        }

                        $newValue = clone $actualValue;
                        $newValue->setOwner($entity, $assoc);
                        $class->reflFields[$propName]->setValue($entity, $newValue);
                    }
                }

                if ($orgValue instanceof PersistentCollection) {
                    // A PersistentCollection was de-referenced, so delete it.
                    $coid = spl_object_id($orgValue);

                    if (isset($this->collectionDeletions[$coid])) {
                        continue;
                    }

                    $this->collectionDeletions[$coid] = $orgValue;
                    $changeSet[$propName]             = $orgValue; // Signal changeset, to-many assocs will be ignored.

                    continue;
                }

                if ($assoc['type'] & ClassMetadata::TO_ONE) {
                    if ($assoc['isOwningSide']) {
                        $changeSet[$propName] = [$orgValue, $actualValue];
                    }

                    if ($orgValue !== null && $assoc['orphanRemoval']) {
                        $this->scheduleOrphanRemoval($orgValue);
                    }
                }
            }

            if ($changeSet) {
                $this->entityChangeSets[$oid]   = $changeSet;
                $this->originalEntityData[$oid] = $actualData;
                $this->entityUpdates[$oid]      = $entity;
            }
        }

        // Look for changes in associations of the entity
        foreach ($class->associationMappings as $field => $assoc) {
            $val = $class->reflFields[$field]->getValue($entity);
            if ($val === null) {
                continue;
            }

            $this->computeAssociationChanges($assoc, $val);

            if (
                ! isset($this->entityChangeSets[$oid]) &&
                $assoc['isOwningSide'] &&
                $assoc['type'] === ClassMetadata::MANY_TO_MANY &&
                $val instanceof PersistentCollection &&
                $val->isDirty()
            ) {
                $this->entityChangeSets[$oid]   = [];
                $this->originalEntityData[$oid] = $actualData;
                $this->entityUpdates[$oid]      = $entity;
            }
        }
    }

    /**
     * Computes all the changes that have been done to entities and collections
     * since the last commit and stores these changes in the _entityChangeSet map
     * temporarily for access by the persisters, until the UoW commit is finished.
     *
     * @return void
     */
    public function computeChangeSets()
    {
        // Compute changes for INSERTed entities first. This must always happen.
        $this->computeScheduleInsertsChangeSets();

        // Compute changes for other MANAGED entities. Change tracking policies take effect here.
        foreach ($this->identityMap as $className => $entities) {
            $class = $this->em->getClassMetadata($className);

            // Skip class if instances are read-only
            if ($class->isReadOnly) {
                continue;
            }

            // If change tracking is explicit or happens through notification, then only compute
            // changes on entities of that type that are explicitly marked for synchronization.
            switch (true) {
                case $class->isChangeTrackingDeferredImplicit():
                    $entitiesToProcess = $entities;
                    break;

                case isset($this->scheduledForSynchronization[$className]):
                    $entitiesToProcess = $this->scheduledForSynchronization[$className];
                    break;

                default:
                    $entitiesToProcess = [];
            }

            foreach ($entitiesToProcess as $entity) {
                // Ignore uninitialized proxy objects
                if ($entity instanceof Proxy && ! $entity->__isInitialized()) {
                    continue;
                }

                // Only MANAGED entities that are NOT SCHEDULED FOR INSERTION OR DELETION are processed here.
                $oid = spl_object_id($entity);

                if (! isset($this->entityInsertions[$oid]) && ! isset($this->entityDeletions[$oid]) && isset($this->entityStates[$oid])) {
                    $this->computeChangeSet($class, $entity);
                }
            }
        }
    }

    /**
     * Computes the changes of an association.
     *
     * @param mixed $value The value of the association.
     * @psalm-param array<string, mixed> $assoc The association mapping.
     *
     * @throws ORMInvalidArgumentException
     * @throws ORMException
     */
    private function computeAssociationChanges(array $assoc, $value): void
    {
        if ($value instanceof Proxy && ! $value->__isInitialized()) {
            return;
        }

        if ($value instanceof PersistentCollection && $value->isDirty()) {
            $coid = spl_object_id($value);

            $this->collectionUpdates[$coid]  = $value;
            $this->visitedCollections[$coid] = $value;
        }

        // Look through the entities, and in any of their associations,
        // for transient (new) entities, recursively. ("Persistence by reachability")
        // Unwrap. Uninitialized collections will simply be empty.
        $unwrappedValue = $assoc['type'] & ClassMetadata::TO_ONE ? [$value] : $value->unwrap();
        $targetClass    = $this->em->getClassMetadata($assoc['targetEntity']);

        foreach ($unwrappedValue as $key => $entry) {
            if (! ($entry instanceof $targetClass->name)) {
                throw ORMInvalidArgumentException::invalidAssociation($targetClass, $assoc, $entry);
            }

            $state = $this->getEntityState($entry, self::STATE_NEW);

            if (! ($entry instanceof $assoc['targetEntity'])) {
                throw UnexpectedAssociationValue::create(
                    $assoc['sourceEntity'],
                    $assoc['fieldName'],
                    get_class($entry),
                    $assoc['targetEntity']
                );
            }

            switch ($state) {
                case self::STATE_NEW:
                    if (! $assoc['isCascadePersist']) {
                        /*
                         * For now just record the details, because this may
                         * not be an issue if we later discover another pathway
                         * through the object-graph where cascade-persistence
                         * is enabled for this object.
                         */
                        $this->nonCascadedNewDetectedEntities[spl_object_id($entry)] = [$assoc, $entry];

                        break;
                    }

                    $this->persistNew($targetClass, $entry);
                    $this->computeChangeSet($targetClass, $entry);

                    break;

                case self::STATE_REMOVED:
                    // Consume the $value as array (it's either an array or an ArrayAccess)
                    // and remove the element from Collection.
                    if ($assoc['type'] & ClassMetadata::TO_MANY) {
                        unset($value[$key]);
                    }

                    break;

                case self::STATE_DETACHED:
                    // Can actually not happen right now as we assume STATE_NEW,
                    // so the exception will be raised from the DBAL layer (constraint violation).
                    throw ORMInvalidArgumentException::detachedEntityFoundThroughRelationship($assoc, $entry);

                    break;

                default:
                    // MANAGED associated entities are already taken into account
                    // during changeset calculation anyway, since they are in the identity map.
            }
        }
    }

    /**
     * @param object $entity
     * @psalm-param ClassMetadata<T> $class
     * @psalm-param T $entity
     *
     * @template T of object
     */
    private function persistNew(ClassMetadata $class, $entity): void
    {
        $oid    = spl_object_id($entity);
        $invoke = $this->listenersInvoker->getSubscribedSystems($class, Events::prePersist);

        if ($invoke !== ListenersInvoker::INVOKE_NONE) {
            $this->listenersInvoker->invoke($class, Events::prePersist, $entity, new LifecycleEventArgs($entity, $this->em), $invoke);
        }

        $idGen = $class->idGenerator;

        if (! $idGen->isPostInsertGenerator()) {
            $idValue = $idGen->generate($this->em, $entity);

            if (! $idGen instanceof AssignedGenerator) {
                $idValue = [$class->getSingleIdentifierFieldName() => $this->convertSingleFieldIdentifierToPHPValue($class, $idValue)];

                $class->setIdentifierValues($entity, $idValue);
            }

            // Some identifiers may be foreign keys to new entities.
            // In this case, we don't have the value yet and should treat it as if we have a post-insert generator
            if (! $this->hasMissingIdsWhichAreForeignKeys($class, $idValue)) {
                $this->entityIdentifiers[$oid] = $idValue;
            }
        }

        $this->entityStates[$oid] = self::STATE_MANAGED;

        $this->scheduleForInsert($entity);
    }

    /**
     * @param mixed[] $idValue
     */
    private function hasMissingIdsWhichAreForeignKeys(ClassMetadata $class, array $idValue): bool
    {
        foreach ($idValue as $idField => $idFieldValue) {
            if ($idFieldValue === null && isset($class->associationMappings[$idField])) {
                return true;
            }
        }

        return false;
    }

    /**
     * INTERNAL:
     * Computes the changeset of an individual entity, independently of the
     * computeChangeSets() routine that is used at the beginning of a UnitOfWork#commit().
     *
     * The passed entity must be a managed entity. If the entity already has a change set
     * because this method is invoked during a commit cycle then the change sets are added.
     * whereby changes detected in this method prevail.
     *
     * @param ClassMetadata $class  The class descriptor of the entity.
     * @param object        $entity The entity for which to (re)calculate the change set.
     * @psalm-param ClassMetadata<T> $class
     * @psalm-param T $entity
     *
     * @return void
     *
     * @throws ORMInvalidArgumentException If the passed entity is not MANAGED.
     *
     * @template T of object
     * @ignore
     */
    public function recomputeSingleEntityChangeSet(ClassMetadata $class, $entity)
    {
        $oid = spl_object_id($entity);

        if (! isset($this->entityStates[$oid]) || $this->entityStates[$oid] !== self::STATE_MANAGED) {
            throw ORMInvalidArgumentException::entityNotManaged($entity);
        }

        // skip if change tracking is "NOTIFY"
        if ($class->isChangeTrackingNotify()) {
            return;
        }

        if (! $class->isInheritanceTypeNone()) {
            $class = $this->em->getClassMetadata(get_class($entity));
        }

        $actualData = [];

        foreach ($class->reflFields as $name => $refProp) {
            if (
                ( ! $class->isIdentifier($name) || ! $class->isIdGeneratorIdentity())
                && ($name !== $class->versionField)
                && ! $class->isCollectionValuedAssociation($name)
            ) {
                $actualData[$name] = $refProp->getValue($entity);
            }
        }

        if (! isset($this->originalEntityData[$oid])) {
            throw new RuntimeException('Cannot call recomputeSingleEntityChangeSet before computeChangeSet on an entity.');
        }

        $originalData = $this->originalEntityData[$oid];
        $changeSet    = [];

        foreach ($actualData as $propName => $actualValue) {
            $orgValue = $originalData[$propName] ?? null;

            if ($orgValue !== $actualValue) {
                $changeSet[$propName] = [$orgValue, $actualValue];
            }
        }

        if ($changeSet) {
            if (isset($this->entityChangeSets[$oid])) {
                $this->entityChangeSets[$oid] = array_merge($this->entityChangeSets[$oid], $changeSet);
            } elseif (! isset($this->entityInsertions[$oid])) {
                $this->entityChangeSets[$oid] = $changeSet;
                $this->entityUpdates[$oid]    = $entity;
            }

            $this->originalEntityData[$oid] = $actualData;
        }
    }

    /**
     * Executes all entity insertions for entities of the specified type.
     */
    private function executeInserts(ClassMetadata $class): void
    {
        $entities  = [];
        $className = $class->name;
        $persister = $this->getEntityPersister($className);
        $invoke    = $this->listenersInvoker->getSubscribedSystems($class, Events::postPersist);

        $insertionsForClass = [];

        foreach ($this->entityInsertions as $oid => $entity) {
            if ($this->em->getClassMetadata(get_class($entity))->name !== $className) {
                continue;
            }

            $insertionsForClass[$oid] = $entity;

            $persister->addInsert($entity);

            unset($this->entityInsertions[$oid]);

            if ($invoke !== ListenersInvoker::INVOKE_NONE) {
                $entities[] = $entity;
            }
        }

        $postInsertIds = $persister->executeInserts();

        if ($postInsertIds) {
            // Persister returned post-insert IDs
            foreach ($postInsertIds as $postInsertId) {
                $idField = $class->getSingleIdentifierFieldName();
                $idValue = $this->convertSingleFieldIdentifierToPHPValue($class, $postInsertId['generatedId']);

                $entity = $postInsertId['entity'];
                $oid    = spl_object_id($entity);

                $class->reflFields[$idField]->setValue($entity, $idValue);

                $this->entityIdentifiers[$oid]            = [$idField => $idValue];
                $this->entityStates[$oid]                 = self::STATE_MANAGED;
                $this->originalEntityData[$oid][$idField] = $idValue;

                $this->addToIdentityMap($entity);
            }
        } else {
            foreach ($insertionsForClass as $oid => $entity) {
                if (! isset($this->entityIdentifiers[$oid])) {
                    //entity was not added to identity map because some identifiers are foreign keys to new entities.
                    //add it now
                    $this->addToEntityIdentifiersAndEntityMap($class, $oid, $entity);
                }
            }
        }

        foreach ($entities as $entity) {
            $this->listenersInvoker->invoke($class, Events::postPersist, $entity, new LifecycleEventArgs($entity, $this->em), $invoke);
        }
    }

    /**
     * @param object $entity
     * @psalm-param ClassMetadata<T> $class
     * @psalm-param T $entity
     *
     * @template T of object
     */
    private function addToEntityIdentifiersAndEntityMap(
        ClassMetadata $class,
        int $oid,
        $entity
    ): void {
        $identifier = [];

        foreach ($class->getIdentifierFieldNames() as $idField) {
            $value = $class->getFieldValue($entity, $idField);

            if (isset($class->associationMappings[$idField])) {
                // NOTE: Single Columns as associated identifiers only allowed - this constraint it is enforced.
                $value = $this->getSingleIdentifierValue($value);
            }

            $identifier[$idField] = $this->originalEntityData[$oid][$idField] = $value;
        }

        $this->entityStates[$oid]      = self::STATE_MANAGED;
        $this->entityIdentifiers[$oid] = $identifier;

        $this->addToIdentityMap($entity);
    }

    /**
     * Executes all entity updates for entities of the specified type.
     */
    private function executeUpdates(ClassMetadata $class): void
    {
        $className        = $class->name;
        $persister        = $this->getEntityPersister($className);
        $preUpdateInvoke  = $this->listenersInvoker->getSubscribedSystems($class, Events::preUpdate);
        $postUpdateInvoke = $this->listenersInvoker->getSubscribedSystems($class, Events::postUpdate);

        foreach ($this->entityUpdates as $oid => $entity) {
            if ($this->em->getClassMetadata(get_class($entity))->name !== $className) {
                continue;
            }

            if ($preUpdateInvoke !== ListenersInvoker::INVOKE_NONE) {
                $this->listenersInvoker->invoke($class, Events::preUpdate, $entity, new PreUpdateEventArgs($entity, $this->em, $this->getEntityChangeSet($entity)), $preUpdateInvoke);

                $this->recomputeSingleEntityChangeSet($class, $entity);
            }

            if (! empty($this->entityChangeSets[$oid])) {
                $persister->update($entity);
            }

            unset($this->entityUpdates[$oid]);

            if ($postUpdateInvoke !== ListenersInvoker::INVOKE_NONE) {
                $this->listenersInvoker->invoke($class, Events::postUpdate, $entity, new LifecycleEventArgs($entity, $this->em), $postUpdateInvoke);
            }
        }
    }

    /**
     * Executes all entity deletions for entities of the specified type.
     */
    private function executeDeletions(ClassMetadata $class): void
    {
        $className = $class->name;
        $persister = $this->getEntityPersister($className);
        $invoke    = $this->listenersInvoker->getSubscribedSystems($class, Events::postRemove);

        foreach ($this->entityDeletions as $oid => $entity) {
            if ($this->em->getClassMetadata(get_class($entity))->name !== $className) {
                continue;
            }

            $persister->delete($entity);

            unset(
                $this->entityDeletions[$oid],
                $this->entityIdentifiers[$oid],
                $this->originalEntityData[$oid],
                $this->entityStates[$oid]
            );

            // Entity with this $oid after deletion treated as NEW, even if the $oid
            // is obtained by a new entity because the old one went out of scope.
            //$this->entityStates[$oid] = self::STATE_NEW;
            if (! $class->isIdentifierNatural()) {
                $class->reflFields[$class->identifier[0]]->setValue($entity, null);
            }

            if ($invoke !== ListenersInvoker::INVOKE_NONE) {
                $this->listenersInvoker->invoke($class, Events::postRemove, $entity, new LifecycleEventArgs($entity, $this->em), $invoke);
            }
        }
    }

    /**
     * Gets the commit order.
     *
     * @return list<object>
     */
    private function getCommitOrder(): array
    {
        $calc = $this->getCommitOrderCalculator();

        // See if there are any new classes in the changeset, that are not in the
        // commit order graph yet (don't have a node).
        // We have to inspect changeSet to be able to correctly build dependencies.
        // It is not possible to use IdentityMap here because post inserted ids
        // are not yet available.
        $newNodes = [];

        foreach (array_merge($this->entityInsertions, $this->entityUpdates, $this->entityDeletions) as $entity) {
            $class = $this->em->getClassMetadata(get_class($entity));

            if ($calc->hasNode($class->name)) {
                continue;
            }

            $calc->addNode($class->name, $class);

            $newNodes[] = $class;
        }

        // Calculate dependencies for new nodes
        while ($class = array_pop($newNodes)) {
            foreach ($class->associationMappings as $assoc) {
                if (! ($assoc['isOwningSide'] && $assoc['type'] & ClassMetadata::TO_ONE)) {
                    continue;
                }

                $targetClass = $this->em->getClassMetadata($assoc['targetEntity']);

                if (! $calc->hasNode($targetClass->name)) {
                    $calc->addNode($targetClass->name, $targetClass);

                    $newNodes[] = $targetClass;
                }

                $joinColumns = reset($assoc['joinColumns']);

                $calc->addDependency($targetClass->name, $class->name, (int) empty($joinColumns['nullable']));

                // If the target class has mapped subclasses, these share the same dependency.
                if (! $targetClass->subClasses) {
                    continue;
                }

                foreach ($targetClass->subClasses as $subClassName) {
                    $targetSubClass = $this->em->getClassMetadata($subClassName);

                    if (! $calc->hasNode($subClassName)) {
                        $calc->addNode($targetSubClass->name, $targetSubClass);

                        $newNodes[] = $targetSubClass;
                    }

                    $calc->addDependency($targetSubClass->name, $class->name, 1);
                }
            }
        }

        return $calc->sort();
    }

    /**
     * Schedules an entity for insertion into the database.
     * If the entity already has an identifier, it will be added to the identity map.
     *
     * @param object $entity The entity to schedule for insertion.
     *
     * @return void
     *
     * @throws ORMInvalidArgumentException
     * @throws InvalidArgumentException
     */
    public function scheduleForInsert($entity)
    {
        $oid = spl_object_id($entity);

        if (isset($this->entityUpdates[$oid])) {
            throw new InvalidArgumentException('Dirty entity can not be scheduled for insertion.');
        }

        if (isset($this->entityDeletions[$oid])) {
            throw ORMInvalidArgumentException::scheduleInsertForRemovedEntity($entity);
        }

        if (isset($this->originalEntityData[$oid]) && ! isset($this->entityInsertions[$oid])) {
            throw ORMInvalidArgumentException::scheduleInsertForManagedEntity($entity);
        }

        if (isset($this->entityInsertions[$oid])) {
            throw ORMInvalidArgumentException::scheduleInsertTwice($entity);
        }

        $this->entityInsertions[$oid] = $entity;

        if (isset($this->entityIdentifiers[$oid])) {
            $this->addToIdentityMap($entity);
        }

        if ($entity instanceof NotifyPropertyChanged) {
            $entity->addPropertyChangedListener($this);
        }
    }

    /**
     * Checks whether an entity is scheduled for insertion.
     *
     * @param object $entity
     *
     * @return bool
     */
    public function isScheduledForInsert($entity)
    {
        return isset($this->entityInsertions[spl_object_id($entity)]);
    }

    /**
     * Schedules an entity for being updated.
     *
     * @param object $entity The entity to schedule for being updated.
     *
     * @return void
     *
     * @throws ORMInvalidArgumentException
     */
    public function scheduleForUpdate($entity)
    {
        $oid = spl_object_id($entity);

        if (! isset($this->entityIdentifiers[$oid])) {
            throw ORMInvalidArgumentException::entityHasNoIdentity($entity, 'scheduling for update');
        }

        if (isset($this->entityDeletions[$oid])) {
            throw ORMInvalidArgumentException::entityIsRemoved($entity, 'schedule for update');
        }

        if (! isset($this->entityUpdates[$oid]) && ! isset($this->entityInsertions[$oid])) {
            $this->entityUpdates[$oid] = $entity;
        }
    }

    /**
     * INTERNAL:
     * Schedules an extra update that will be executed immediately after the
     * regular entity updates within the currently running commit cycle.
     *
     * Extra updates for entities are stored as (entity, changeset) tuples.
     *
     * @param object $entity The entity for which to schedule an extra update.
     * @psalm-param array<string, array{mixed, mixed}>  $changeset The changeset of the entity (what to update).
     *
     * @return void
     *
     * @ignore
     */
    public function scheduleExtraUpdate($entity, array $changeset)
    {
        $oid         = spl_object_id($entity);
        $extraUpdate = [$entity, $changeset];

        if (isset($this->extraUpdates[$oid])) {
            [, $changeset2] = $this->extraUpdates[$oid];

            $extraUpdate = [$entity, $changeset + $changeset2];
        }

        $this->extraUpdates[$oid] = $extraUpdate;
    }

    /**
     * Checks whether an entity is registered as dirty in the unit of work.
     * Note: Is not very useful currently as dirty entities are only r…