Doctrine\ODM\PHPCR\ReferenceManyCollection::takeSnapshot PHP Method

    public function takeSnapshot()
    {
        if (is_array($this->originalReferencePaths)) {
            if ($this->isInitialized()) {
                foreach ($this->collection->toArray() as $document) {
                    try {
                        $this->originalReferencePaths[] = $this->dm->getUnitOfWork()->getDocumentId($document);
                    } catch (PHPCRException $e) {
                    }
                }
            } else {
                $this->originalReferencePaths = null;
            }
        }
        parent::takeSnapshot();
    }