fix: adopt potentially changed file extension when downloading

src/Controller/Administrative/Document/BatchDownloadController.php

@@ -59,6 +59,12 @@ class BatchDownloadController extends AbstractController
                 /** @var Upload $upload */
                 $filename = $upload->getOriginalFilename();
                 $filepath = $this->uploadHandler->getUploadFilepath($upload);
+                $extension = pathinfo($filepath, PATHINFO_EXTENSION);
+
+                // adopt potentially changed file extension
+                if (false === str_ends_with($filename, $extension)) {
+                    $filename = $filename.'.'.$extension;
+                }
 
                 try {
                     $zip->addFileFromPath(fileName: $filename, path: $filepath);

src/Controller/Common/DownloadController.php

@@ -29,7 +29,15 @@ class DownloadController extends AbstractController
     public function index(Upload $upload, Request $request): Response
     {
         $path = $this->uploadHandler->getUploadFilepath($upload);
+        $extension = pathinfo($path, PATHINFO_EXTENSION);
+
+        // adopt potentially changed file extension
         $originalFilename = $upload->getOriginalFilename();
+
+        if (false === str_ends_with($originalFilename, $extension)) {
+            $originalFilename = $originalFilename.'.'.$extension;
+        }
+
         $inline = (bool) $request->get('inline');
         $disposition = $inline ? ResponseHeaderBag::DISPOSITION_INLINE : ResponseHeaderBag::DISPOSITION_ATTACHMENT;