Don't mutate literals in tabulated-list-widen-current-column

* lisp/emacs-lisp/tabulated-list.el
(tabulated-list-widen-current-column): Avoid mutating constants
(bug#53501).

diff --git a/lisp/emacs-lisp/tabulated-list.el b/lisp/emacs-lisp/tabulated-list.el
index 2defef81073ff2b3d8c6d14e8b834cf8174ea987..b740a7457af9bd93638ce24a0042a018556791a7 100644 (file)
--- a/lisp/emacs-lisp/tabulated-list.el
+++ b/lisp/emacs-lisp/tabulated-list.el
@@ -755,6 +755,9 @@ Interactively, N is the prefix numeric argument, and defaults to
                            1))))
           (setq col-nb (1+ col-nb))
         (setq found t)
+        ;; `tabulated-list-format' may be a constant (sharing list
+        ;; structures), so copy it before mutating.
+        (setq tabulated-list-format (copy-tree tabulated-list-format t))
         (setf (cadr (aref tabulated-list-format col-nb))
               (max 1 (+ col-width n)))
         (tabulated-list-print t)