diff --git a/lisp/lib/files.el b/lisp/lib/files.el
index 022be0003..94b47d4a3 100644
--- a/lisp/lib/files.el
+++ b/lisp/lib/files.el
@@ -594,7 +594,12 @@ see), and if nil, defaults to `find-sibling-rules'."
                       (nconc
                        results
                        (mapcar #'expand-file-name
-                               (file-expand-wildcards expansion nil t)))))))))
+                               ;; `file-expand-wildcards' has a new REGEXP
+                               ;; argument in 29+ that is needed here. This swap
+                               ;; makes it behave as if REGEXP == t.
+                               (letf! (defun wildcard-to-regexp (wildcard)
+                                        (concat "\\`" wildcard "\\'"))
+                                 (file-expand-wildcards expansion nil))))))))))
       ;; Delete the file itself (in case it matched), and remove
       ;; duplicates, in case we have several expansions and some match
       ;; the same subsets of files.