Adam G-H
--- a/src/ComposerStager/Cleaner.php 0 → 100644
+++ b/src/ComposerStager/Cleaner.php 0 → 100644
+    $this->pathLocator = $locator;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function clean(string $stagingDir, ?ProcessOutputCallbackInterface $callback, ?int $timeout = 120): void {
+    // Ensure that the staged site directory is writable.
+    $site_dir = implode(DIRECTORY_SEPARATOR, [
+      $stagingDir,
+      $this->pathLocator->getWebRoot() ?: '.',
+      $this->sitePath,
+    ]);
+
+    if ($this->directoryExists($site_dir)) {
+      (new Filesystem())->chmod($site_dir, 0777);