Internal: Check if data file for migration exists

src/CoreBundle/Migrations/AbstractMigrationChamilo.php

@@ -410,9 +410,13 @@ abstract class AbstractMigrationChamilo extends AbstractMigration
     {
         $fullFilename = $this->generateFilePath($filename);
 
+        if ($this->fileExists($fullFilename)) {
             return file_get_contents($fullFilename);
         }
 
+        return '';
+    }
+
     protected function removeFile(string $filename): void
     {
         $fullFilename = $this->generateFilePath($filename);