EntityMerger::mergeFields

public function mergeFields(array &$seed, array &$targ, $skipEmpty = false, array $options = array())
{
	$entityFieldInfos = $this->getEntityFieldsInfo();
	$userFieldInfos = $this->getEntityUserFieldsInfo();

	$this->innerMergeEntityFields($seed, $targ, $entityFieldInfos, $skipEmpty, $options);
	EntityMerger::mergeUserFields($seed, $targ, $userFieldInfos, $options);

	$seedMultiFields = isset($seed['FM']) && is_array($seed['FM']) ? $seed['FM'] : array();
	$targMultiFields = isset($targ['FM']) && is_array($targ['FM']) ? $targ['FM'] : array();

	//Skip multifields if target fields is defined in skipempty mode.
	if(!$skipEmpty || empty($targMultiFields))
	{
		EntityMerger::mergeMultiFields($seedMultiFields, $targMultiFields, $skipEmpty);
	}

	if(!empty($targMultiFields))
	{
		$targ['FM'] = $targMultiFields;
	}
}