emacs-28 81f20e8: Fix thinko in ls-lisp--insert-directory

[Michael Albinus]

branch: emacs-28
commit 81f20e8b89d6333cbc796e92df5aa3df4f5712db
Author: Michael Albinus <michael.albinus@gmx.de>
Commit: Michael Albinus <michael.albinus@gmx.de>

    Fix thinko in ls-lisp--insert-directory
    
    * lisp/ls-lisp.el (ls-lisp--insert-directory): Ensure that
    SWITCHES is a string.
---
 lisp/ls-lisp.el | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lisp/ls-lisp.el b/lisp/ls-lisp.el
index 8e81f79..82153ff 100644
--- a/lisp/ls-lisp.el
+++ b/lisp/ls-lisp.el
@@ -283,6 +283,7 @@ are also supported; unsupported long options are silently 
ignored."
       (funcall orig-fun
               file switches wildcard full-directory-p)
     ;; We need the directory in order to find the right handler.
+    (setq switches (or switches ""))
     (let ((handler (find-file-name-handler (expand-file-name file)
                                           'insert-directory))
          (orig-file file)