symfony - Warning: spl_object_hash() expects parameter 1 to be object, string given -

i have issues "warning: spl_object_hash() expects parameter 1 object, string given" when try save onetomay entity side of relationship, code below may give ideas:

<?php  namespace backendbundle\entity;  use doctrine\common\collections\arraycollection; use doctrine\orm\mapping orm;   /**  * bulletinsalaire  *  * @orm\table(name="bulletin_salaire")  * @orm\entity(repositoryclass="backendbundle\repository\bulletinsalairerepository")  */ class bulletinsalaire {     /**      * @var int      *      * @orm\column(name="id", type="integer")      * @orm\id      * @orm\generatedvalue(strategy="auto")      */     private $id;       /**      * @var \datetime      *      * @orm\column(name="periode", type="date")      */     private $periode;      /**      * @var string      *      * @orm\column(name="mode_reglement", type="string", length=255)      */     private $modereglement;      /**      *      * @orm\manytoone(targetentity="employee", inversedby="employees", cascade={"persist"})      * @orm\joincolumn(name="id_employee", referencedcolumnname="id")      */      private $employee;      /**      *      * @orm\onetomany(targetentity="libellebulletin", mappedby="bulletinsalaire", cascade={"persist"})      * @orm\joincolumn(name="id_libellebulltin", referencedcolumnname="id")      */      private $libellebulletins;      public function __construct()     {         $this->libellebulletins= new arraycollection();     }      /**      * id      *      * @return int      */     public function getid()     {         return $this->id;     }      /**      * set libelle      *      * @param string $libelle      *      * @return bulletinsalaire      */     public function setlibelle($libelle)     {         $this->libelle = $libelle;          return $this;     }      /**      * libelle      *      * @return string      */     public function getlibelle()     {         return $this->libelle;     }      /**      * set base      *      * @param integer $base      *      * @return bulletinsalaire      */     public function setbase($base)     {         $this->base = $base;          return $this;     }      /**      * base      *      * @return int      */     public function getbase()     {         return $this->base;     }      /**      * set retenues      *      * @param float $retenues      *      * @return bulletinsalaire      */     public function setretenues($retenues)     {         $this->retenues = $retenues;          return $this;     }      /**      * retenues      *      * @return float      */     public function getretenues()     {         return $this->retenues;     }      /**      * set periode      *      * @param \datetime $periode      *      * @return bulletinsalaire      */     public function setperiode($periode)     {         $this->periode = $periode;          return $this;     }      /**      * periode      *      * @return \datetime      */     public function getperiode()     {         return $this->periode;     }      /**      * set modereglement      *      * @param string $modereglement      *      * @return bulletinsalaire      */     public function setmodereglement($modereglement)     {         $this->modereglement = $modereglement;          return $this;     }      /**      * modereglement      *      * @return string      */     public function getmodereglement()     {         return $this->modereglement;     }      /**      * @return mixed      */     public function getemployee()     {         return $this->employee;     }      /**      * @param mixed $employee      */     public function setemployee($employee)     {         $this->employee = $employee;     }       /**      * @param libellebulletin $libellebulletin      * @return $this      */     public function addlibellebulletin(libellebulletin $libellebulletin)     {         $this->libellebulletins[] = $libellebulletin;         $libellebulletin->setbulletinsalaire($this);          return $this;     }      /**      * @param libellebulletin $libellebulletin      */     public function removelibellebulletin(libellebulletin $libellebulletin)     {         $this->libellebulletins->removeelement($libellebulletin);     }      public function getlibellebulletins()     {         return $this->libellebulletins;     }  }      /---------------------entity many libelle 1 bulletin de salaire ----------------/ <?php /**  * created phpstorm.  * user: achouri  * date: 17/11/2016  * time: 4:05 pm  */  namespace backendbundle\entity;  use doctrine\orm\mapping orm;   /**  * bulletinsalaire  *  * @orm\table(name="libelle_bulletins")  * @orm\entity()  */  class libellebulletin {     /**      * @var int      *      * @orm\column(name="id", type="integer")      * @orm\id      * @orm\generatedvalue(strategy="auto")      */     private $id;     /**      * @orm\manytoone(targetentity="bulletinsalaire", inversedby="libellebulletins")      * @orm\joincolumn(nullable=false)      */     private $bulletinsalaire;      /**      * @var string      *      * @orm\column(name="libelle", type="string", length=255)      *      */     private $libelle;      /**      * @var int      *      * @orm\column(name="base", type="integer")      */     private $base;      /**      * @var float      *      * @orm\column(name="retenues", type="float")      */     private $retenues;      /**      * @return int      */     public function getid()     {         return $this->id;     }      /**      * @param int $id      */     public function setid($id)     {         $this->id = $id;     }      /**      * @return string      */     public function getlibelle()     {         return $this->libelle;     }      /**      * @param string $libelle      */     public function setlibelle($libelle)     {         $this->libelle = $libelle;     }      /**      * @return int      */     public function getbase()     {         return $this->base;     }      /**      * @param int $base      */     public function setbase($base)     {         $this->base = $base;     }      /**      * @return float      */     public function getretenues()     {         return $this->retenues;     }      /**      * @param float $retenues      */     public function setretenues($retenues)     {         $this->retenues = $retenues;     }      /**      * @return mixed      */     public function getbulletinsalaire()     {         return $this->bulletinsalaire;     }      /**      * @param mixed $bulletinsalaire      */     public function setbulletinsalaire($bulletinsalaire)     {         $this->bulletinsalaire = $bulletinsalaire;     }   }      /---------------------bulletinsallairetype---------------------------/ <?php  namespace backendbundle\form;  use symfony\bridge\doctrine\form\type\entitytype; use symfony\component\form\abstracttype; use symfony\component\form\formbuilderinterface; use symfony\component\optionsresolver\optionsresolver; use backendbundle\form\libellebulletintype; class bulletinsalairetype extends abstracttype {     /**      * {@inheritdoc}      */     public function buildform(formbuilderinterface $builder, array $options)     {         $builder->add('libellebulletins',libellebulletintype::class,array('label' => '','data_class' => null))             ->add('periode')->add('modereglement')             ->add('employee',entitytype::class,array('attr'   =>  array(             'class'   => 'form-control'),             'class' => 'backendbundle:employee',             'choice_label' => function ($employee) {                 return $employee->getnom()." ".$employee->getprenom();             }));     }      /**      * {@inheritdoc}      */     public function configureoptions(optionsresolver $resolver)     {         $resolver->setdefaults(array(             'data_class' => 'backendbundle\entity\bulletinsalaire'         ));     }      /**      * {@inheritdoc}      */     public function getblockprefix()     {         return 'backendbundle_bulletinsalaire';     }   } /------------------------libellebultintype-----------------------/ <?php  namespace backendbundle\form;  use symfony\bridge\doctrine\form\type\entitytype; use symfony\component\form\abstracttype; use symfony\component\form\formbuilderinterface; use symfony\component\optionsresolver\optionsresolver; use backendbundle\form\employeetype; class libellebulletintype extends abstracttype {     /**      * {@inheritdoc}      */     public function buildform(formbuilderinterface $builder, array $options)     {         $builder->add('libelle')->add('base')->add('retenues');     }      /**      * {@inheritdoc}      */     public function configureoptions(optionsresolver $resolver)     {         $resolver->setdefaults(array(             'data_class' => 'backendbundle\entity\libellebulletin'         ));     }      /**      * {@inheritdoc}      */     public function getblockprefix()     {         return 'backendbundle_libellebulletin';     }   } /----------------------action du save-----------------/     /**      * creates new bulletinsalaire entity.      *      * @route("/new", name="bulletinsalaire_new")      * @method({"get", "post"})      */     public function newaction(request $request)     {         $bulletinsalaire = new bulletinsalaire();         $libellebulletin= new libellebulletin();         $form = $this->createform('backendbundle\form\bulletinsalairetype', $bulletinsalaire);         $form->handlerequest($request);          if ($form->issubmitted() && $form->isvalid()) {             $em = $this->getdoctrine()->getmanager();             $bulletinsalaire->addlibellebulletin($libellebulletin);             $em->persist($bulletinsalaire);             $em->flush($bulletinsalaire);              return $this->redirecttoroute('bulletinsalaire_show', array('id' => $bulletinsalaire->getid()));         }          return $this->render('backendbundle:bulletinsalaire:new.html.twig', array(             'bulletinsalaire' => $bulletinsalaire,             'form' => $form->createview(),         ));     } 

as @xabbuh pointed, need see how create object. looks trying set $employee or $libellebulletins string instead of object.

this wrong.

$bulletin->setemployee('some value'); 

this right.

$employee = $dm->getrepository('backendbundle:employee')->findonebyid('employeeid');  $bulletin->setemployee($employee);