.../EventSubscriber/DynamicPageCacheSubscriber.php | 44 +++++++++++-----------
 1 file changed, 21 insertions(+), 23 deletions(-)

diff --git a/core/modules/dynamic_page_cache/src/EventSubscriber/DynamicPageCacheSubscriber.php b/core/modules/dynamic_page_cache/src/EventSubscriber/DynamicPageCacheSubscriber.php
index 35087b1..17c2f33 100644
--- a/core/modules/dynamic_page_cache/src/EventSubscriber/DynamicPageCacheSubscriber.php
+++ b/core/modules/dynamic_page_cache/src/EventSubscriber/DynamicPageCacheSubscriber.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheableMetadata;
-use Drupal\Core\Cache\CacheableResponse;
 use Drupal\Core\Cache\CacheableResponseInterface;
 use Drupal\Core\EventSubscriber\MainContentViewSubscriber;
 use Drupal\Core\PageCache\RequestPolicyInterface;
@@ -47,11 +46,19 @@ class DynamicPageCacheSubscriber implements EventSubscriberInterface {
    * Attribute name of the Dynamic Page Cache request policy result.
    *
    * @see onRouteMatch()
-   * @see onRespond()
+   * @see onResponse()
    */
   const ATTRIBUTE_REQUEST_POLICY_RESULT = '_dynamic_page_cache_request_policy_result';
 
   /**
+   * Attribute name of the controller's render array #cache check.
+   *
+   * @see onViewRenderArray()
+   * @see onResponse()
+   */
+  const ATTRIBUTE_CONTROLLER_RESULT_RENDER_ARRAY_HAS_CACHEABILITY = '_dynamic_page_cache_controller_render_array_has_cacheability';
+
+  /**
    * Name of Dynamic Page Cache's response header.
    */
   const HEADER = 'X-Drupal-Dynamic-Cache';
@@ -157,35 +164,17 @@ public function onRouteMatch(GetResponseEvent $event) {
    * @param \Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent $event
    *   The event to process.
    *
-   * @throws \LogicException
+   * @see ::onResponse()
    */
   public function onViewRenderArray(GetResponseForControllerResultEvent $event) {
     $request = $event->getRequest();
     $result = $event->getControllerResult();
 
-    // Don't complain if Dynamic Page Cache's request subscriber did not fire,
-    // because that means it is impossible to have a Dynamic Page Cache hit,
-    // and hence complaining is unnecessary.
-    // @see ::onResponse()
-    if (!$request->attributes->has(self::ATTRIBUTE_REQUEST_POLICY_RESULT)) {
-      return;
-    }
-
-    // Don't complain if the Dynamic Page Cache request & response policies are
-    // not met, because that means Dynamic Page Cache won't cache this response
-    // and hence complaining is unnecessary.
-    // @see onRouteMatch()
-    if ($request->attributes->get(self::ATTRIBUTE_REQUEST_POLICY_RESULT) === RequestPolicyInterface::DENY || $this->responsePolicy->check(new CacheableResponse(), $request) === ResponsePolicyInterface::DENY) {
-      return;
-    }
-
     // Check if MainContentViewSubscriber would render this render array, i.e.
     // if this render array will in fact be converted into a response.
     if (is_array($result) && ($request->query->has(MainContentViewSubscriber::WRAPPER_FORMAT) || $request->getRequestFormat() == 'html')) {
-      // If #cache is not set, complain.
-      if (!isset($result['#cache'])) {
-        throw new \LogicException('The controller returned a render array without cacheability metadata. See https://www.drupal.org/developing/api/8/render/arrays/cacheability.');
-      }
+      // If #cache is not set, complain later.
+      $request->attributes->set(self::ATTRIBUTE_CONTROLLER_RESULT_RENDER_ARRAY_HAS_CACHEABILITY, isset($result['#cache']));
     }
   }
 
@@ -194,6 +183,8 @@ public function onViewRenderArray(GetResponseForControllerResultEvent $event) {
    *
    * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
    *   The event to process.
+   *
+   * @throws \LogicException
    */
   public function onResponse(FilterResponseEvent $event) {
     $response = $event->getResponse();
@@ -241,6 +232,13 @@ public function onResponse(FilterResponseEvent $event) {
       return;
     }
 
+    // If #cache was not set, complain.
+    // @see ::onViewRenderArray()
+    // If #cache is not set, complain.
+    if ($request->attributes->get(self::ATTRIBUTE_CONTROLLER_RESULT_RENDER_ARRAY_HAS_CACHEABILITY) === FALSE) {
+      throw new \LogicException('The controller returned a render array without cacheability metadata. See https://www.drupal.org/developing/api/8/render/arrays/cacheability.');
+    }
+
     // Embed the response object in a render array so that RenderCache is able
     // to cache it, handling cache redirection for us.
     $response_as_render_array = $this->responseToRenderArray($response);