Merge pull request #47 from pantheon-systems/bugs-5478

[BUGS-5478] Skip clearing keys on install.php page.

pantheon_advanced_page_cache.services.yml

@@ -4,6 +4,7 @@ services:
     arguments: ['pantheon_advanced_page_cache']
   pantheon_advanced_page_cache.cache_tags.invalidator:
     class: Drupal\pantheon_advanced_page_cache\CacheTagsInvalidator
+    arguments: ['@request_stack']
     tags:
       - { name: cache_tags_invalidator }
   pantheon_advanced_page_cache.cacheable_response_subscriber:

src/CacheTagsInvalidator.php

@@ -3,16 +3,39 @@
 namespace Drupal\pantheon_advanced_page_cache;
 
 use Drupal\Core\Cache\CacheTagsInvalidatorInterface;
+use Symfony\Component\HttpFoundation\RequestStack;
 
 /**
  * Cache tags invalidator implementation that invalidates the Pantheon edge.
  */
 class CacheTagsInvalidator implements CacheTagsInvalidatorInterface {
 
+  /**
+   * The request stack.
+   *
+   * @var \Symfony\Component\HttpFoundation\RequestStack
+   */
+  protected $requestStack;
+
+  /**
+   * Construct.
+   */
+  public function __construct(RequestStack $request_stack) {
+    $this->requestStack = $request_stack;
+  }
+
   /**
    * {@inheritdoc}
    */
   public function invalidateTags(array $tags) {
+    $do_not_run_urls = [
+      // There is a weird interaction with metatag that clear local_tasks key
+      // and therefore lots of cached pages.
+      '/core/install.php',
+    ];
+    if (in_array($this->requestStack->getCurrentRequest()->getBaseUrl(), $do_not_run_urls)) {
+      return;
+    }
     if (function_exists('pantheon_clear_edge_keys')) {
       pantheon_clear_edge_keys($tags);
     }