Issue #3104421 by peterkokot: PHP 7.4 deprecated reverse order of glue and pieces in implode

core/lib/Drupal/Core/FileTransfer/FileTransfer.php

@@ -363,7 +363,7 @@ public function findChroot() {
     $parts = explode('/', $path);
     $chroot = '';
     while (count($parts)) {
-      $check = implode($parts, '/');
+      $check = implode('/', $parts);
       if ($this->isFile($check . '/' . \Drupal::service('file_system')->basename(__FILE__))) {
         // Remove the trailing slash.
         return substr($chroot, 0, -1);

core/modules/inline_form_errors/tests/src/Unit/FormErrorHandlerTest.php

@@ -138,7 +138,7 @@ public function testErrorMessagesInline() {
         foreach ($render_array[1]['#items'] as $item) {
           $links[] = htmlspecialchars($item['#title']);
         }
-        return $render_array[0]['#markup'] . '<ul-comma-list-mock><li-mock>' . implode($links, '</li-mock><li-mock>') . '</li-mock></ul-comma-list-mock>';
+        return $render_array[0]['#markup'] . '<ul-comma-list-mock><li-mock>' . implode('</li-mock><li-mock>', $links) . '</li-mock></ul-comma-list-mock>';
       }));
 
     $form_state = new FormState();