Issue #3261847: Add helpful methods to compute the difference between two ComposerUtility objects

src/Validator/StagedProjectsValidator.php

@@ -39,8 +39,6 @@ final class StagedProjectsValidator implements EventSubscriberInterface {
       return;
     }
 
-    $active = $stage->getActiveComposer();
-    $stage = $stage->getStageComposer();
     $type_map = [
       'drupal-module' => $this->t('module'),
       'drupal-custom-module' => $this->t('custom module'),
@@ -51,6 +49,9 @@ final class StagedProjectsValidator implements EventSubscriberInterface {
       return array_key_exists($package->getType(), $type_map);
     };
     try {
+      $active = $stage->getActiveComposer();
+      $stage = $stage->getStageComposer();
+
       $new_packages = array_filter($active->getPackagesAddedBy($stage), $filter);
       $removed_packages = array_filter($active->getPackagesRemovedBy($stage), $filter);
       $updated_packages = array_filter($active->getPackagesUpdatedBy($stage), $filter);