Issue #3214630 by dcam, rpayanm, larowlan, Darren Oh: Invalidate /aggregator...

Issue #3214630 by dcam, rpayanm, larowlan, Darren Oh: Invalidate /aggregator page cache when feeds update

core/modules/aggregator/src/Controller/AggregatorController.php

@@ -176,6 +176,7 @@ public function pageLast() {
     $items = $this->entityTypeManager()->getStorage('aggregator_item')->loadAll(20);
     $build = $this->buildPageList($items);
     $build['#attached']['feed'][] = ['aggregator/rss', $this->config('system.site')->get('name') . ' ' . $this->t('aggregator')];
+    $build['#cache']['tags'] = $this->entityTypeManager()->getDefinition('aggregator_item')->getListCacheTags();
     return $build;
   }
 

core/modules/aggregator/tests/src/Functional/AggregatorRenderingTest.php

@@ -100,9 +100,21 @@ public function testFeedPage() {
 
     // Create a feed with 30 items.
     $this->createSampleNodes(30);
+
+    // Request the /aggregator page so that it is cached.
+    $this->drupalGet('aggregator');
+
     $feed = $this->createFeed();
     $this->updateFeedItems($feed, 30);
 
+    // Verify that items are loaded on the page by checking for the pager.
+    $this->drupalGet('aggregator');
+    $this->assertSession()->elementExists('xpath', '//ul[contains(@class, "pager__items")]');
+
+    // Save the feed entity to invalidate the cache so that the paginated cache
+    // context can be tested.
+    $feed->save();
+
     // Request page with no feed items to ensure cache context is set correctly.
     $this->drupalGet('aggregator', ['query' => ['page' => 2]]);
     // Check for presence of an aggregator pager.