Looping through entities and updating them causes error on flush - symfony

Question

I am new to symfony and doctrine. And I am compeleting a code that someone else has started. I mainly have a form for which I wrote a validation function in my controller. In this form a BusReservation object along with its BusReservationDetails are created and saved to the db. so at the end of the form validation function, after the entities are saved in DB, I call a BusReservation Manager method which is transformBusReservationDetailIntoBusTicket which aim is to take each BusReservationDetail in the BusReservation oject and create a a new entity BusTicket based on it.
so I created this loop (please let me know if there is something wrong in my code so that i can write in a good syntax). I tried to put the 3 persist that you see at the end of the code but I got : Notice: Undefined index: 0000000..
I tried to merge (the last 3 lines in code ) I got the following :
A new entity was found through the relationship 'MyBundle\Entity\CustomInfo#busTicket' that was not configured to cascade persist operations for entity: . To solve this issue: Either explicitly call EntityManager#persist() on this unknown entity or configure cascade persist this association in the mapping for example #ManyToOne(..,cascade={"persist"}).
I got this same error when i commented all theh 6 lines of merge and flush.
PS: I am not expecting the flush to fully work. There are some properties that are nullable=false so I assume that I must set them as well so that the entities can be saved to DB. But the error i got is by far different than this.
PS : I noticed that there is a onFlush where the customInfo is updated and persisted again and other things happen, but i am trying to debug step by step. I tried to detach this event but still got the same errors. so I want to fix my code and make sure that the code part that i wrote in the manager is correct and if that's the case then I can move to debugging the event Listener. so please I would like to know if the following code is correct and why the flush is not working.
/**
* #param $idBusReservation
* #return bool
* #throws \Doctrine\ORM\NonUniqueResultException
*/
public function transformBusReservationIntoBusTicket($idBusReservation): bool
{ $result = "into the function";
/** #var BusReservation $busReservation */
$busReservation = $this->em->getRepository('MyBundle:BusReservation')->find($idBusReservation);
if ($busReservation !== null) {
/** #var BusReservationDetail $busReservationDetail */
foreach ($busReservation->getBusReservationDetails() as $busReservationDetail) {
$busTicket = new BusTicket($busReservationDetail->getBusModel(), $busReservation->getPassenger());
$busReservationDetail->setBusTicket($busTicket);
$busTicket->setBusReservationDetail($busReservationDetail);
$busTicket->setOwner($busreservation->getPassenger()->getName());
if ($busReservationDetail->getBusModel()->getCode() === 'VIPbus') {
// perform some logic .. later on
} else {
$customInfo = new CustomInfo();
$customInfo->setNumber(1551998);
// $customInfo->setCurrentMode(
// $this->em->getRepository('MyBundle:Mode')
// ->find(['code' => 'Working'])
// );
$customInfo->setBusTicket($busTicket);
// Bus ticket :
$busTicket->addCustomInfo($customInfo);
$busTicket->setComment($busReservation->getComment());
}
/** #var Mode $currentMode */
$currentMode = $this->em->getRepository('MyBundle:Mode')
->findOneBy(['code' => 'Working']);
$busTicket->setCurrentMode($currentMode);
// $this->em->merge($customInfo);
// $this->em->merge($busReservationDetail);
// $this->em->merge($busTicket);
// $this->em->persist($customInfo);
// $this->em->persist($busReservationDetail);
// $this->em->persist($busTicket);
}
$this->em->flush();
// $this->em->clear();
}
return $result;
}
// *************** In BusReservation.php ********************
/**
* #ORM\OneToMany(targetEntity="MyBundle\Entity\BusReservationDetail", mappedBy="busReservation")
*/
private $busReservationDetails;
/**
* Get busReservationDetails
*
*#return Collection
*/
public function getBusReservationDetails()
{
return $this->busReservationDetails;
}
// ---------------------------------------------------------------------
// *************** In BusReservationDetail.php ********************
/**
* #ORM\ManyToOne(targetEntity="MyBundle\Entity\BusReservation", inversedBy="busReservationDetails")
* #ORM\JoinColumn(name="id_bus_reservation", referencedColumnName="id_bus_reservation", nullable=false)
*/
private $busReservation;
/**
* #ORM\ManyToOne(targetEntity="MyBundle\Entity\BusModel")
* #ORM\JoinColumn(name="bus_model_code", referencedColumnName="bus_model_code", nullable=false)
*/
private $busModel;
/**
* #ORM\OneToOne(targetEntity="MyBundle\Entity\BusTicket", inversedBy="busReservationDetail", cascade={"merge","remove","persist"})
* #ORM\JoinColumn(name="id_bus_ticket", referencedColumnName="id_bus_ticket")
*/
private $busTicket;
/**
* #return BusModel
*/
public function getBusModel()
{
return $this->busModel;
}
//-------------------------------------------------------------------------
// ************ IN BusTicket.php *****************************
/**
* #ORM\OneToMany(targetEntity="MyBundle\Entity\CustomInfo", mappedBy="busTicket")
*/
private $customInfos;
/**
*
* #param CustomInfo $customInfo
*
* #return BusTicket
*/
public function addCustomInfot(CustomInfo $customInfo)
{
if (!$this->customInfos->contains($customInfo)) {
$this->customInfos[] = $customInfo;
}
return $this;
}
/**
* #ORM\OneToOne(targetEntity="MyBundle\Entity\busReservationDetail", mappedBy="busTicket")
*/
private $busReservationDetail;
// --------------------------------------------------------------------
// CUSTOMINFO ENTITY
/**
* #ORM\ManyToOne(targetEntity="MyBundle\Entity\BusTicket", inversedBy="customInfos")
* #ORM\JoinColumn(name="id_bus_ticket", referencedColumnName="id_bus_ticket", nullable=false)
*/
private $busTicket;

Answer 1

The answer is in your error message. You either have to add cascade={"persist"} to your entity annotation, or explicitly call persist. I don't believe you need em->merge() in this situation as you're never taking the entities out of context.
Where you have all your persist lines commented out, just try putting this in
$this->em->persist($busTicket);
$this->em->persist($busReservationDetail);
$this->em->persist($customInfo);
and if you're looping through a ton of entities, you could try adding the flush inside the loop at the end instead of a huge flush at the end.