Issue #3232420: Create a service which can recommend a target version of core

src/UpdateRecommender.php

@@ -20,6 +20,12 @@ class UpdateRecommender {
    * @return \Drupal\automatic_updates_9_3_shim\ProjectRelease|null
    *   A value object with information about the recommended release, or NULL
    *   if Drupal core is already up-to-date.
+   *
+   * @throws \RuntimeException
+   *   If data about available updates cannot be retrieved.
+   * @throws \LogicException
+   *   If Drupal core is out of date and the recommended version of cannot be
+   *   determined.
    */
   public function getRecommendedRelease(array &$project): ?ProjectRelease {
     $available_updates = update_get_available(TRUE);
@@ -36,7 +42,7 @@ class UpdateRecommender {
     }
     // If we don't know what to recommend they update to, time to freak out.
     elseif (empty($project['recommended'])) {
-      throw new \LogicException('Could not determine the recommended version of Drupal core.');
+      throw new \LogicException('Drupal core is out of date, but the recommended version could not be determined.');
     }
 
     $recommended_version = $project['recommended'];