Fix list-colors-print handling of callback arg

* lisp/facemenu.el (list-colors-print): Keeping
backward-compatibility, don't fail when passed a closure object as
CALLBACK.  (Bug#45831)

1 files changed, 8 insertions, 3 deletions

diff --git a/lisp/facemenu.el b/lisp/facemenu.el
index 2609397b0d9..dc5f8f46aba 100644
--- a/lisp/facemenu.el
+++ b/lisp/facemenu.el
@@ -606,9 +606,14 @@ color.  The function should accept a single argument, the color name."
 
 (defun list-colors-print (list &optional callback)
   (let ((callback-fn
-         (if callback
-             `(lambda (button)
-                (funcall ,callback (button-get button 'color-name))))))
+         ;; Expect CALLBACK to be a function, but allow it to be a form that
+         ;; evaluates to a function, for backward-compatibility.  (Bug#45831)
+         (cond ((functionp callback)
+                (lambda (button)
+                  (funcall callback (button-get button 'color-name))))
+               (callback
+                `(lambda (button)
+                  (funcall ,callback (button-get button 'color-name)))))))
     (dolist (color list)
       (if (consp color)
           (if (cdr color)