Add a check for Libraries API module and warn users about the dependency being dropped

drupal-org-core.make

@@ -8,4 +8,4 @@ projects[drupal][download][tag] = 8.8.2
 projects[drupal][patch][] = https://www.drupal.org/files/issues/2020-02-07/2869592-remove-update-warning-34.patch
 projects[drupal][patch][] = https://www.drupal.org/files/issues/2019-11-05/1356276-531-8.8.x-4.patch
 projects[drupal][patch][] = https://www.drupal.org/files/issues/2018-07-09/2914389-8-do-not-test.patch
-projects[drupal][patch][] = https://www.drupal.org/files/issues/2019-11-27/2815221-125.patch
+projects[drupal][patch][] = https://www.drupal.org/files/issues/2019-11-27/2815221-125.patch

lightning.install

@@ -9,6 +9,34 @@ use Drupal\Core\Entity\Entity\EntityViewDisplay;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\lightning_core\ConfigHelper as Config;
 
+/**
+ * Alerts users of Libraries API dependencies.
+ *
+ * A future version of Lightning will remove Libraries API, so
+ * users must add that dependency to composer.json manually.
+ */
+function lightning_requirements() {
+    $requirements = [];
+    $libraries_dependencies = [];
+    $enabled_modules = \Drupal::moduleHandler()->getModuleList();
+
+    foreach ($enabled_modules as $module => $data) {
+        $info = \Drupal::service('extension.list.module')->getExtensionInfo($module);
+        if (in_array('drupal:libraries', $info['dependencies'])) {
+            $libraries_dependencies[$module] = $info['name'];
+        }
+    }
+
+    if ($enabled_modules) {
+        $requirements['lightning_libraries'] = [
+            'title' => t('Libraries API dependencies'),
+            'value' => t('These modules require Libraries API: %module_list. Lightning will soon remove Libraries API as a dependency, so you must add that dependency to your composer.json manually.', ['%module_list' => implode(', ', $libraries_dependencies)]),
+            'severity' => REQUIREMENT_WARNING,
+        ];
+    }
+    return $requirements;
+}
+
 /**
  * Makes updates to some basic config that ships with Lightning.
  *