Add Method not working in a many to many relationship - doctrine-orm

Question

I have this many to many relationship between bus and driver .
This is the bus entity :
/**
* #var ArrayCollection<Driver> The driver of this bus.
* #ORM\ManyToMany(targetEntity="Driver", inversedBy="bus" , cascade={"persist"})
* #ORM\JoinTable(name="bus_driver")
* #ORM\JoinColumn(name="driver_id", referencedColumnName="id")
* */
private $driver;
public function __construct() {
$this->driver = new \Doctrine\Common\Collections\ArrayCollection();
}
public function addDriver($driver) {
$this->driver[] = $driver;
return $this;
}
And this is the driver entity :
/**
* #var ArrayCollection<Bus> The buses of this driver
* #ORM\ManyToMany(targetEntity="Bus", mappedBy="driver")
* #ORM\JoinTable(name="bus_driver")
* #ORM\JoinColumn(name="bus_id", referencedColumnName="id")
*/
private $bus;
public function __construct() {
$this->bus = new \Doctrine\Common\Collections\ArrayCollection();
}
public function addBus($bus) {
$this->bus[] = $bus;
$bus->addDriver($this);
return $this;
}
My problem is that when I add a bus with a driver the relation is persisted but not when I add a driver whih a bus . It works only from the bus side.

Answer 1

please, consider renaming $driver into $drivers, as there is multiple drivers (same for bus -> buses)
and then you should try that:
#ORM\ManyToMany(targetEntity="xxx", cascade={"persist"})
more details: http://doctrine-orm.readthedocs.io/projects/doctrine-orm/en/latest/reference/working-with-associations.html#transitive-persistence-cascade-operations

Answer 2

Change these (add the null and call it 'drivers'):
use Doctrine\Common\Collections\ArrayCollection;
...
private $drivers = null;
public function __construct() {
$this->drivers = new ArrayCollection();
}
public function addDriver($driver) {
$this->drivers[] = $driver;
return $this;
}
Also, to resolve the problem from the Bus Entity side, you might (but I'm not sure) need this change:
public function addDriver($driver) {
$driver->addBus($this);
$this->drivers[] = $driver;
return $this;
}
Try it, since I have a similar scenario in a ManyToOne relation, and I'm wondering if the above change might work.

Answer 3

The only working scenario was when I had :
A setter for the drivers collection .
An addDriver Method .
A removeDriver Method.
If I remove one of the pervious , addDriver won't even trigger at all .