Issue #2910506 by Aron Novak, bartlangelaan, maximpodorov, luca_loguercio,...

   * {@inheritdoc}

   */

  public function linkExistingAccount(string $authname, string $provider, UserInterface $account) {

    // If a mapping (for the same provider) to this account already exists, we

    // silently skip saving this auth mapping.

    if (!$this->authmap->get($account->id(), $provider)) {

    // If a mapping (for the same provider) to this account already exists, and

    // the authname is the same, we silently skip saving this auth mapping.

    $current_authname = $this->authmap->get($account->id(), $provider);

    if ($current_authname === $authname) {

      return;

    }

    // If we update the authmap entry, let's log the change.

    if (!empty($current_authname)) {

      $this->logger->debug('Authmap change (%old => %new) for user %name with uid %uid from provider %provider', [

        '%old' => $current_authname,

        '%new' => $authname,

        '%name' => $account->getAccountName(),

        '%uid' => $account->id(),

        '%provider' => $provider,

      ]);

    }

    $authmap_event = $this->eventDispatcher->dispatch(new ExternalAuthAuthmapAlterEvent($provider, $authname, $account->getAccountName(), NULL), ExternalAuthEvents::AUTHMAP_ALTER);

    $this->authmap->save($account, $provider, $authmap_event->getAuthname(), $authmap_event->getData());

  }

  }

}