diff --git a/core/modules/migrate/src/Plugin/Migration.php b/core/modules/migrate/src/Plugin/Migration.php
index 9b22e35..5b4b895 100644
--- a/core/modules/migrate/src/Plugin/Migration.php
+++ b/core/modules/migrate/src/Plugin/Migration.php
@@ -662,7 +662,7 @@ public function setTrackLastImported($track_last_imported) {
    * {@inheritdoc}
    */
   public function getMigrationDependencies() {
-    return $this->migration_dependencies + ['required' => [], 'optional' => []];
+    return ($this->migration_dependencies ?: []) + ['required' => [], 'optional' => []];
   }
 
   /**