diff -u b/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php
--- b/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php
@@ -141,35 +141,25 @@
     // for that is stored in the current render context. If the current route is
     // not cacheable we simply discard it.
     if (!$context->isEmpty() && !$this->routeMatch->getRouteObject()->getOption('no_cache')) {
-      /** @var \Drupal\Core\Render\BubbleableMetadata $early_rendering_bubbleable_metadata */
-      $early_rendering_bubbleable_metadata = $context->pop();
-
       // If a render array is returned by the controller, merge the "lost"
       // bubbleable metadata.
       if (is_array($response)) {
+        $early_rendering_bubbleable_metadata = $context->pop();
         BubbleableMetadata::createFromRenderArray($response)
           ->merge($early_rendering_bubbleable_metadata)
           ->applyTo($response);
       }
-
-      // If a Response object is returned, and it cares about cacheability, then
-      // add the dependency.
-      if ($response instanceof CacheableResponseInterface) {
-        $response->addCacheableDependency($early_rendering_bubbleable_metadata);
-      }
-      // If a domain object is returned, and it cares about cacheability, then
-      // throw an exception: early rendering is not permitted in that case. It
-      // is the developer's responsibility to not use early rendering.
-      elseif ($response instanceof CacheableDependencyInterface) {
+      // If a Response or domain object is returned, and it cares about
+      // attachments or cacheability, then throw an exception: early rendering
+      // is not permitted in that case. It is the developer's responsibility
+      // to not use early rendering.
+      elseif ($response instanceof AttachmentsInterface || $response instanceof CacheableResponseInterface || $response instanceof CacheableDependencyInterface) {
         throw new \LogicException(sprintf('The controller result claims to be providing relevant cache metadata, but leaked metadata was detected. Please ensure you are not rendering content too early. Returned object class: %s.', get_class($response)));
       }
-
-      // If a Response or domain object is returned, and it cares about
-      // attachments, and early rendering required additional attachments then
-      // throw an exception: early rendering is not permitted in that case. It
-      // is the developer's responsibility to not use early rendering.
-      elseif ($response instanceof AttachmentsInterface && $early_rendering_bubbleable_metadata->getAttachments()) {
-        throw new \LogicException(sprintf('The controller result claims to be providing relevant attachments, but leaked attachments were detected. Please ensure you are not rendering content too early. Returned object class: %s.', get_class($response)));
+      else {
+        // A Response or domain object is returned that does not care about
+        // attachments nor cacheability. E.g. a RedirectResponse. It is safe to
+        // discard any early rendering metadata.
       }
     }
 
diff -u b/core/lib/Drupal/Core/Render/CacheableMetadataAwareUrlGenerator.php b/core/lib/Drupal/Core/Render/CacheableMetadataAwareUrlGenerator.php
--- b/core/lib/Drupal/Core/Render/CacheableMetadataAwareUrlGenerator.php
+++ b/core/lib/Drupal/Core/Render/CacheableMetadataAwareUrlGenerator.php
@@ -8,8 +8,8 @@
 namespace Drupal\Core\Render;
 
 use Drupal\Core\GeneratedUrl;
+use Drupal\Core\PageCache\RequestPolicyInterface;
 use Drupal\Core\Routing\UrlGeneratorInterface;
-use Drupal\Core\UncacheableUrl;
 use Symfony\Component\Routing\RequestContext as SymfonyRequestContext;
 
 /**
@@ -74,18 +74,22 @@
    *
    * @param \Drupal\Core\GeneratedUrl $generated_url
    *   The generated URL whose bubbleable metadata to bubble.
-   * @param array $options
-   *   (optional) The URL options. Defaults to none.
    */
-  protected function bubble(GeneratedUrl $generated_url, array $options = []) {
-    // Bubbling metadata makes sense only if the code is executed inside a
-    // render context. All code running outside controllers has no render
-    // context by default, so URLs used there are not supposed to affect the
-    // response cacheability.
-    if (empty($options[UncacheableUrl::UNCACHEABLE_OPTION]) && $this->renderer->hasRenderContext()) {
-      $build = [];
-      $generated_url->applyTo($build);
-      $this->renderer->render($build);
+  protected function bubble(GeneratedUrl $generated_url) {
+    if ($generated_url->affectsCacheability()) {
+      if ($this->renderer->hasRenderContext()) {
+        $build = [];
+        $generated_url->applyTo($build);
+        $this->renderer->render($build);
+      }
+      else {
+        $request_policy = \Drupal::service('page_cache_request_policy');
+        $request = \Drupal::requestStack()->getCurrentRequest();
+        $request_is_cacheable = $request_policy->check($request) === RequestPolicyInterface::ALLOW;
+        if ($request_is_cacheable) {
+          throw new \LogicException('A generated URL affects cacheability, but has no render context into which to add that information.');
+        }
+      }
     }
   }
 
@@ -105,7 +109,7 @@
   public function generateFromRoute($name, $parameters = array(), $options = array(), $collect_cacheability_metadata = FALSE) {
     $generated_url = $this->urlGenerator->generateFromRoute($name, $parameters, $options, TRUE);
     if (!$collect_cacheability_metadata) {
-      $this->bubble($generated_url, $options);
+      $this->bubble($generated_url);
     }
     return $collect_cacheability_metadata ? $generated_url : $generated_url->getGeneratedUrl();
   }
@@ -116,7 +120,7 @@
   public function generateFromPath($path = NULL, $options = array(), $collect_cacheability_metadata = FALSE) {
     $generated_url = $this->urlGenerator->generateFromPath($path, $options, TRUE);
     if (!$collect_cacheability_metadata) {
-      $this->bubble($generated_url, $options);
+      $this->bubble($generated_url);
     }
     return $collect_cacheability_metadata ? $generated_url : $generated_url->getGeneratedUrl();
   }
diff -u b/core/modules/simpletest/src/WebTestBase.php b/core/modules/simpletest/src/WebTestBase.php
--- b/core/modules/simpletest/src/WebTestBase.php
+++ b/core/modules/simpletest/src/WebTestBase.php
@@ -2811,20 +2811,20 @@
    *   Options to be passed to Url::fromUri().
    *
    * @return string
-   *   An absolute URL stsring.
+   *   An absolute URL string.
    */
   protected function buildUrl($path, array $options = array()) {
     if ($path instanceof Url) {
       $url_options = $path->getOptions();
       $options = $url_options + $options;
       $path->setOptions($options);
-      return $path->setAbsolute()->toString();
+      return $path->setAbsolute()->toString(TRUE)->getGeneratedUrl();
     }
     // The URL generator service is not necessarily available yet; e.g., in
     // interactive installer tests.
     else if ($this->container->has('url_generator')) {
       $options['absolute'] = TRUE;
-      return $this->container->get('url_generator')->generateFromPath($path, $options);
+      return $this->container->get('url_generator')->generateFromPath($path, $options, TRUE)->getGeneratedUrl();
     }
     else {
       return $this->getAbsoluteUrl($path);
diff -u b/core/modules/system/src/Tests/Common/EarlyRenderingControllerTest.php b/core/modules/system/src/Tests/Common/EarlyRenderingControllerTest.php
--- b/core/modules/system/src/Tests/Common/EarlyRenderingControllerTest.php
+++ b/core/modules/system/src/Tests/Common/EarlyRenderingControllerTest.php
@@ -59,7 +59,7 @@
     $this->assertNoCacheTag('foo');
     $this->drupalGet(Url::fromRoute('early_rendering_controller_test.response-with-attachments.early'));
     $this->assertResponse(500);
-    $this->assertRaw('The controller result claims to be providing relevant attachments, but leaked attachments were detected. Please ensure you are not rendering content too early. Returned object class: Drupal\early_rendering_controller_test\AttachmentsTestResponse.');
+    $this->assertRaw('The controller result claims to be providing relevant cache metadata, but leaked metadata was detected. Please ensure you are not rendering content too early. Returned object class: Drupal\early_rendering_controller_test\AttachmentsTestResponse.');
     $this->drupalGet(Url::fromRoute('early_rendering_controller_test.response-with-attachments.early_no_cache'));
     $this->assertResponse(200);
     $this->assertRaw('Hello world!');
@@ -95,7 +95,7 @@
     $this->assertNoCacheTag('foo');
     $this->drupalGet(Url::fromRoute('early_rendering_controller_test.domain-object-with-attachments.early'));
     $this->assertResponse(500);
-    $this->assertRaw('The controller result claims to be providing relevant attachments, but leaked attachments were detected. Please ensure you are not rendering content too early. Returned object class: Drupal\early_rendering_controller_test\AttachmentsTestDomainObject.');
+    $this->assertRaw('The controller result claims to be providing relevant cache metadata, but leaked metadata was detected. Please ensure you are not rendering content too early. Returned object class: Drupal\early_rendering_controller_test\AttachmentsTestDomainObject.');
     $this->drupalGet(Url::fromRoute('early_rendering_controller_test.domain-object-with-attachments.early_no_cache'));
     $this->assertResponse(200);
     $this->assertRaw('AttachmentsTestDomainObject');
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Cache/CacheableMetadata.php
+++ b/core/lib/Drupal/Core/Cache/CacheableMetadata.php
@@ -179,6 +179,15 @@ public function merge(CacheableMetadata $other) {
   }
 
   /**
+   * Checks if the current values affect cacheability.
+   *
+   * @return bool
+   */
+  public function affectsCacheability() {
+    return !empty($this->contexts) || !empty($this->tags) || ($this->maxAge !== Cache::PERMANENT);
+  }
+
+  /**
    * Applies the values of this CacheableMetadata object to a render array.
    *
    * @param array &$build
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/EventSubscriber/RedirectResponseSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/RedirectResponseSubscriber.php
@@ -82,7 +82,7 @@ public function checkRedirectUrl(FilterResponseEvent $event) {
             $options['fragment'] = $destination['fragment'];
             // The 'Location' HTTP header must always be absolute.
             $options['absolute'] = TRUE;
-            $destination = $this->urlGenerator->generateFromPath($path, $options);
+            $destination = $this->urlGenerator->generateFromPath($path, $options, TRUE)->getGeneratedUrl();
           }
           $response->setTargetUrl($destination);
         }