FOSUserBundle/Symfony3:在更改当前密码之前检查它

我使用的是Symfony3和FOSUserBundle。

我要求他们输入他们的旧密码和新的所需密码,我想检查旧密码是否与当前记录的密码相同。

出于某种奇怪的原因,编码器不断返回错误的散列。我做错了什么?

    $user = $this->getUser();
    $newPasswordPlain = 'newpassword';
    $currentPasswordForValidation = 'test';

    $encoder_service = $this->get('security.encoder_factory');
    $encoder = $encoder_service->getEncoder($user);
    $encodedPassword = $encoder->encodePassword($currentPasswordForValidation, $user->getSalt());

    var_dump( $encodedPassword);
    var_dump( $user->getPassword());

    if ( $user->getPassword() == $encodedPassword ) {
        $userManager = $this->container->get('fos_user.user_manager');
        $user->setPlainPassword($newPasswordPlain);
        $userManager->updateUser($user, true);
    } else {
        var_dump('error: not the same password'); exit;
    }