Infinite redirect if you do not have access to the page.

This fixes the issue for me.

Re #4: can you expound what you mean? I don't follow you? The destination should be to a local resource. It includes 'internal:' as the prefix. So pushing that into a LocalRedirectResponse should not have any problems, no?

I cannot reproduce what you are seeing. Are you visiting multiple urls one, after another and it isn't working?

patch #2 applies cleanly to 8.x-1.12 and fixes infinite redirect loop for non-anonymous paths on our production site. marking RTBC.

I'm not able to reproduce the issue currently from #4/#6 currently, but off and on I am. And I think the reason is due to browser caching. Let's see if this fixes those outliers.

#10 works a treat, thanks. Clear your cache if you run into issues after applying the patch.

Patch #10 not working on my side (Drupal 8.6.2 / require_login 8.x-1.12) ...

Here is the fatal error :

ArgumentCountError: Too few arguments to function Drupal\require_login\EventSubscriber\RequireLoginSubscriber::__construct(), 6 passed in /mysite/html/web/core/lib/Drupal/Component/DependencyInjection/Container.php on line 282 and exactly 8 expected in Drupal\require_login\EventSubscriber\RequireLoginSubscriber->__construct() (line 103 of modules/contrib/require_login/src/EventSubscriber/RequireLoginSubscriber.php). 

Patch applyed with composer cweagans/composer-patches

Any idea ?

EDIT : simply apply cache rebuild after patching if you are in same situation !

Seems like we have 2 corroborating testers of the patch in #10. So on to RTBC.

like #13, I also had to rebuild cache to get past the "Too few arguments" error. should there be an update hook to eliminate that? this wasn't encountered with patch in #2.

Good point. Needs an empty update hook to clear cache.

Tagging novice.

The prior example in the module had a call to drupal's clear cache functionality so I replicated it. Happy to change that if necessary.

Patch from #18 worked great against 1.12. Thanks everyone!

This patch works great but all the rearranging of use statements means I can't also apply the patch from #3012100: URL parameters not preserved after login. The attached patch combines the two together.

HttpExceptionSubscriberBase should be extended with an on403() method to handle redirects from normally access restricted pages. May have to rework EventSubscriberInterface to avoid stacked redirect responses that would totally defeat the fix.

Edit:
Should be able to use KernelEvents::EXCEPTION in getSubscribedEvents() instead of extending HttpExceptionSubscriberBase.

Issue has been fixed in latest code refactor and has been committed to the 8.x-1.x branch. New releases will be created soon.

Thanks for working on this @metzlerd and @heddn. Though the patches weren't used the discussion shed light on some fundamental implementation flaws. I'm not going into much detail since a lot has changed in the refactor but the solution involved an additional event subscriber on KernelEvents::EXCEPTION.

  /**
   * Login redirect on KernelEvents::EXCEPTION.
   *
   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
   *   The event response.
   */
  public function exceptionRedirect(GetResponseEvent $event) {

    // Boolean to indicate request exception. Prevents additional login
    // requirement checks on KernelEvents::REQUEST which could cause
    // infinite loop redirects on protected pages.
    $this->requestException = TRUE;

    if ($redirect = $this->prepareLoginRedirect($event)) {
      $response = new RedirectResponse($redirect);
      $event->setResponse($response);
    }
  }

  /**
   * Login redirect on KernelEvents::REQUEST.
   *
   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
   *   The event response.
   */
  public function requestRedirect(GetResponseEvent $event) {
    if (!$this->requestException && ($redirect = $this->prepareLoginRedirect($event))) {
      $response = new RedirectResponse($redirect);
      $event->setResponse($response);
    }
  }

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() {
    $events[KernelEvents::EXCEPTION][] = ['exceptionRedirect'];
    $events[KernelEvents::REQUEST][] = ['requestRedirect'];
    return $events;
  }