Issue #3053804 by heddn, catch: Checker: Are there pending updates (update.php needs to be run)

automatic_updates.services.yml

@@ -61,3 +61,7 @@ services:
       - '@automatic_updates.drupal_finder'
     tags:
       - { name: readiness_checker, category: warning}
+  automatic_updates.pending_db_updates:
+    class: Drupal\automatic_updates\ReadinessChecker\PendingDbUpdates
+    tags:
+      - { name: readiness_checker, category: error}

src/ReadinessChecker/PendingDbUpdates.php

+<?php
+
+namespace Drupal\automatic_updates\ReadinessChecker;
+
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+
+/**
+ * Pending database updates checker.
+ */
+class PendingDbUpdates implements ReadinessCheckerInterface {
+  use StringTranslationTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function run() {
+    $messages = [];
+
+    if ($this->areDbUpdatesPending()) {
+      $messages[] = $this->t('There are pending database updates, therefore updates cannot be applied. Please run update.php.');
+    }
+    return $messages;
+  }
+
+  /**
+   * Checks if there are pending database updates.
+   *
+   * @return bool
+   *   TRUE if there are pending updates, otherwise FALSE.
+   */
+  protected function areDbUpdatesPending() {
+    require_once DRUPAL_ROOT . '/core/includes/install.inc';
+    require_once DRUPAL_ROOT . '/core/includes/update.inc';
+    drupal_load_updates();
+    return (bool) update_get_update_list();
+  }
+
+}

tests/src/Kernel/ReadinessChecker/PendingDbUpdatesTest.php

+<?php
+
+namespace Drupal\Tests\automatic_updates\Kernel\ReadinessChecker;
+
+use Drupal\automatic_updates\ReadinessChecker\PendingDbUpdates;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests pending db updates readiness checking.
+ *
+ * @group automatic_updates
+ */
+class PendingDbUpdatesTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = [
+    'automatic_updates',
+  ];
+
+  /**
+   * Tests pending db updates readiness checks.
+   */
+  public function testPendingDbUpdates() {
+    $messages = $this->container->get('automatic_updates.pending_db_updates')->run();
+    $this->assertEmpty($messages);
+
+    $messages = (new TestPendingDbUpdates())->run();
+    $this->assertEquals('There are pending database updates, therefore updates cannot be applied. Please run update.php.', $messages[0]);
+  }
+
+}
+
+/**
+ * Class TestPendingDbUpdates.
+ */
+class TestPendingDbUpdates extends PendingDbUpdates {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function areDbUpdatesPending() {
+    return TRUE;
+  }
+
+}