From 132893deb168ccb9dfb033bd2203690883b4fc1f Mon Sep 17 00:00:00 2001
From: Kristiaan Van den Eynde <kristiaan@factorial.io>
Date: Mon, 15 Apr 2019 13:43:04 +0200
Subject: [PATCH] interdiff

---
 core/lib/Drupal/Core/Render/RenderCache.php | 40 ++++++++++++---------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/core/lib/Drupal/Core/Render/RenderCache.php b/core/lib/Drupal/Core/Render/RenderCache.php
index 873d680c65..c425cfa44a 100644
--- a/core/lib/Drupal/Core/Render/RenderCache.php
+++ b/core/lib/Drupal/Core/Render/RenderCache.php
@@ -83,12 +83,20 @@ public function get(array $elements) {
       // have an accurate representation of its cache tags or max-age. Both
       // might have changed during the folding of cache contexts, but its not
       // the variation cache's job to update the thing it's supposed to cache.
-      // Given how we rely on the '#cache' key to be accurate, we update it with
-      // the cache metadata from the cache.
-      $cacheability = CacheableMetadata::createFromRenderArray($cached_element);
-      $cacheability->addCacheTags($cache->tags);
-      $cacheability->mergeCacheMaxAge($this->expireToMaxAge($cache->expire));
-      $cacheability->applyTo($cached_element);
+      //
+      // Given how we rely on the element's '#cache' key to be an accurate
+      // representation of how the element is cached, we update the element with
+      // the cache metadata from the cache object as that's where the tags and
+      // max-age might have changed while setting the cache object.
+      //
+      // We also need to remove the 'rendered' cache tag as that one is internal
+      // to the render cache and shouldn't have come from the actual element.
+      $cache_tags = $cache->tags;
+      if (($key = array_search('rendered', $cache_tags, TRUE)) !== FALSE) {
+        unset($cache_tags[$key]);
+      }
+      $cached_element['#cache']['tags'] = $cache_tags;
+      $cached_element['#cache']['max-age'] = $this->expireToMaxAge($cache->expire);
 
       // Return the cached element.
       return $cached_element;
@@ -148,11 +156,11 @@ public function set(array &$elements, array $pre_bubbling_elements) {
       //   ],
       // ]
       //
-      // This efficiently lets cacheGet() redirect to a $cid that includes all
-      // of the required contexts. The strategy is on-demand: in the case where
-      // there aren't any additional contexts required by children that aren't
-      // already included in the parent's pre-bubbled #cache information, no
-      // cache redirection is needed.
+      // This efficiently lets get() redirect to a $cid that includes all of the
+      // required contexts. The strategy is on-demand: in the case where there
+      // aren't any additional contexts required by children that aren't already
+      // included in the parent's pre-bubbled #cache information, no cache
+      // redirection is needed.
       //
       // When implementing this redirection strategy, special care is needed to
       // resolve potential cache ping-pong problems. For example, consider the
@@ -246,14 +254,14 @@ public function set(array &$elements, array $pre_bubbling_elements) {
       //   redirect, because the last update's max-age would always "win".)
       $redirect_cacheability_updated = CacheableMetadata::createFromRenderArray($data)->merge($redirect_cacheability);
 
+      // Manipulate the post-bubbling cache keys so that we store the cache
+      // redirect at the original cache keys' entry and the actual post-bubbling
+      // element at the manipulated cache keys' entry.
+      array_unshift($element_cache_keys, 'render_cache_redirect');
+
       // Stored cache contexts incomplete: this request causes cache contexts to
       // be added to the redirecting cache item.
       if (array_diff($redirect_cacheability_updated->getCacheContexts(), $redirect_cacheability->getCacheContexts())) {
-        // Manipulate the post-bubbling cache keys so that we store the cache
-        // redirect at the original cache keys' entry and the actual
-        // post-bubbling element at the manipulated cache keys' entry.
-        array_unshift($element_cache_keys, 'render_cache_redirect');
-
         $redirect_data = [
           '#cache_redirect' => TRUE,
           '#cache' => [
-- 
2.17.1