fix validation for notification

src/Bundle/ChillMainBundle/Entity/Notification.php

@@ -17,6 +17,7 @@ use DateTimeInterface;
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
 use Doctrine\ORM\Mapping as ORM;
+use Symfony\Component\Validator\Constraints as Assert;
 
 /**
  * @ORM\Entity
@@ -32,6 +33,7 @@ class Notification implements TrackUpdateInterface
     /**
      * @ORM\ManyToMany(targetEntity=User::class)
      * @ORM\JoinTable(name="chill_main_notification_addresses_user")
+     * @Assert\Count(min="1", minMessage="notification.At least one addressee")
      */
     private Collection $addressees;
 
@@ -80,6 +82,7 @@ class Notification implements TrackUpdateInterface
 
     /**
      * @ORM\Column(type="text", options={"default": ""})
+     * @Assert\NotBlank(message="notification.Title must be defined")
      */
     private string $title = '';
 
@@ -286,9 +289,9 @@ class Notification implements TrackUpdateInterface
         return $this;
     }
 
-    public function setMessage(string $message): self
+    public function setMessage(?string $message): self
     {
-        $this->message = $message;
+        $this->message = (string) $message;
 
         return $this;
     }
@@ -314,9 +317,9 @@ class Notification implements TrackUpdateInterface
         return $this;
     }
 
-    public function setTitle(string $title): Notification
+    public function setTitle(?string $title): Notification
     {
-        $this->title = $title;
+        $this->title = (string) $title;
 
         return $this;
     }