php - Object exist BUT trying to get property on a non object -

im working on project on laravel5 php 5.5.12 , mysql 5.6.17 yesterday working fine, when come code today, have error "trying property of non-object" on multiple models objects, case occurs when have relationships other models.

if write :

$test = $model->relation->property; 

i error.

if write :

echo / var_dump($model->relation->property); 

then printed no problem.

i don't know happen , appreciated.

ps: sorry if im wrong text wrote, first time ask question on stackoverflow :) oh , did read similar questions

this stay.php model :

namespace app\models;  use illuminate\database\eloquent\model;  class stay extends custommodel {  protected $table = 'stay';  protected $fillable = array('reservation_terms_convention_id', 'reservation_id', 'period_id', 'total_price', 'price_ht', 'occupant_id', 'prestation_fixe_id', 'pax', 'checkin', 'checkout');  protected $guarded = array('id');  static public $mailtemplatingwhitelist = ['total_price'];  public static $rules = [ 'reservation_terms_convention_id' => 'required|exists:reservation_terms_convention,id', 'period_id' => 'required|exists:period,id', 'payeur_id' => 'required' ];       public function payment_due_date()     {         return $this->belongsto('app\models\paymentduedate','payment_due_date_id', 'id');     } } 

here related model :

<?php namespace app\models;  use illuminate\database\eloquent\model;  class paymentduedate extends custommodel {   protected $table = 'payment_due_date';  protected $fillable = array('total_amount', 'acompte_amount', 'amount_ht', 'amount_already_payed', 'payment_total_date', 'payment_acompte_date',         'facturation_date', 'description_facture', 'type', 'cash_desk_id', 'individual_customer_id',         'partner_id', 'direction');  protected $guarded = array('id');   public function stay(){     return $this->hasone('app\models\stay'); }  } 

and controller :

public function print_partner_invoice($partner_id, $echeance = 0)      $partner = partner::find($partner_id);      // return collection of model     $partner_resa = partner::reservations_echeance($partner->id, $echeance);      if(!$partner || $partner_resa->count() < 1)         abort(403);        $residence_company = $partner_resa->first()->residence->residence_company;      $total_ttc = 0;     $already_paid = 0;     $tva_amount = 0;       foreach ($partner_resa $key => $resa) {          foreach ($resa->stays $key => $stay) {             $amount = $stay->payment_due_date->total_amount;         }      }      $pdf = \pdf::loadview('reglement.partner_invoice', [         'partner'               => $partner,         'resas'                 => $partner_resa,         'residence_company'     => $residence_company,         'total_ttc'             => $total_ttc,         'already_paid'          => $already_paid,         'tva_amount'            => $tva_amount         ]);      return $pdf->stream(); } 

first, if write

var_dump($doesnotexists1->doesnotexists2->doesnotexists3);  

its null, there no error, because var_dump looks $doesnotexists1, , if null not looking further. no "trying property of non-object in " execption.

so, problem maybe $stay or $stay->payment_due_date at

 $amount = $stay->payment_due_date->total_amount; 

is null/empty.

i check

foreach ($partner_resa $key => $resa) {      foreach ($resa->stays $key => $stay) {       if(is_object(stay) && is_object($stay->payment_due_date)) {         $amount = $stay->payment_due_date->total_amount;       }     } } 

to sure object