Issue #3382942: Eliminate dependencies on Composer Stager internals

package_manager/src/Event/PreApplyEvent.php

@@ -4,6 +4,7 @@ declare(strict_types = 1);
 
 namespace Drupal\package_manager\Event;
 
+use Drupal\package_manager\ImmutablePathList;
 use Drupal\package_manager\StageBase;
 use PhpTuf\ComposerStager\API\Path\Value\PathListInterface;
 
@@ -12,19 +13,27 @@ use PhpTuf\ComposerStager\API\Path\Value\PathListInterface;
  */
 final class PreApplyEvent extends PreOperationStageEvent {
 
+  /**
+   * The list of paths to ignore in the active and stage directories.
+   *
+   * @var \Drupal\package_manager\ImmutablePathList
+   */
+  public readonly ImmutablePathList $excludedPaths;
+
   /**
    * Constructs a PreApplyEvent object.
    *
    * @param \Drupal\package_manager\StageBase $stage
    *   The stage which fired this event.
-   * @param \PhpTuf\ComposerStager\API\Path\Value\PathListInterface $excludedPaths
+   * @param \PhpTuf\ComposerStager\API\Path\Value\PathListInterface $excluded_paths
    *   The list of paths to exclude. These will not be copied from the stage
    *   directory to the active directory, nor be deleted from the active
    *   directory if they exist, when the stage directory is copied back into
    *   the active directory.
    */
-  public function __construct(StageBase $stage, public readonly PathListInterface $excludedPaths) {
+  public function __construct(StageBase $stage, PathListInterface $excluded_paths) {
     parent::__construct($stage);
+    $this->excludedPaths = new ImmutablePathList($excluded_paths);
   }
 
 }