Pimcore\Model\Object\ClassDefinition\Data\Fieldcollections::resolveDependencies PHP Method

    public function resolveDependencies($data)
    {
        $dependencies = [];
        if ($data instanceof Object\Fieldcollection) {
            foreach ($data as $item) {
                if (!$item instanceof Object\Fieldcollection\Data\AbstractData) {
                    continue;
                }
                try {
                    $collectionDef = Object\Fieldcollection\Definition::getByKey($item->getType());
                } catch (\Exception $e) {
                    continue;
                }
                foreach ($collectionDef->getFieldDefinitions() as $fd) {
                    $getter = "get" . ucfirst($fd->getName());
                    $dependencies = array_merge($dependencies, $fd->resolveDependencies($item->{$getter}()));
                }
            }
        }
        return $dependencies;
    }