fix: remove logic to set user id in the passed User object

Modifying the object gives the false impression of database equivalency.
We have no created/updated timestamps, or other fields coming from the database,
or effects of stored procedures and field defaults.

Author: kenjis

src/Models/UserModel.php

@@ -232,11 +232,6 @@ public function insert($data = null, bool $returnID = true)
 
         $this->checkQueryReturn($result);
 
-        // Set user id to the passed User object.
-        if ($data instanceof User) {
-            $data->id = $this->insertID;
-        }
-
         return $returnID ? $this->insertID : $result;
     }
 

tests/Unit/UserModelTest.php

@@ -5,6 +5,7 @@
 namespace Tests\Unit;
 
 use CodeIgniter\Shield\Entities\User;
+use CodeIgniter\Shield\Exceptions\LogicException;
 use CodeIgniter\Shield\Models\UserModel;
 use CodeIgniter\Test\DatabaseTestTrait;
 use Tests\Support\TestCase;
@@ -67,14 +68,15 @@ public function testInsertUserObject(): void
      */
     public function testSaveNewUserAndGetEmailIdentity(): void
     {
+        $this->expectException(LogicException::class);
+        $this->expectExceptionMessage('"$user->id" is null. You should not use the incomplete User object.');
+
         $users = $this->createUserModel();
         $user  = $this->createNewUser();
 
         $users->save($user);
 
-        $identity = $user->getEmailIdentity();
-
-        $this->assertSame('foo@bar.com', $identity->secret);
+        $user->getEmailIdentity();
     }
 
     /**