Re: describe-key: Wrong type argument: sequencep, C-up

[Alan Mackenzie <acm@muc.de>]

Hello again, Zhang.

On Fri, Dec 29, 2017 at 09:14:55 +0000, Alan Mackenzie wrote:
> On Fri, Dec 29, 2017 at 04:31:39 +0000, zhang cc wrote:
> > Run the command: describe-key, then press the key Control-up, and emacs report the following error message:
> > describe-key: Wrong type argument: sequencep, C-up

> > Emacs: 26.0.90
> > OS: macOS 10.13.2

> Yes.  A careless `copy-sequence' has been used.

> I'll fix it.

I've committed the following patch to the emacs-26 branch which should
fix the bug.  Thanks for taking the trouble to report it.


commit b240c7846b0d03e9f69af753cd24eb1e550f543c
Author: Alan Mackenzie <acm@muc.de>
Date:   Fri Dec 29 09:54:03 2017 +0000

    * lisp/help.el (describe-key): Only (copy-sequence elt) when elt is a list.

diff --git a/lisp/help.el b/lisp/help.el
index fa7f6b0d5b..8ff27b0b24 100644
--- a/lisp/help.el
+++ b/lisp/help.el
@@ -876,7 +876,7 @@ describe-key
         (when (vectorp key)
           (let* ((last (1- (length key)))
                  (elt (aref key last))
-                 (elt-1 (copy-sequence elt))
+                 (elt-1 (if (listp elt) (copy-sequence elt) elt))
                  key-1 down-event-type)
             (when (and (listp elt-1)
                        (symbolp (car elt-1))


-- 
Alan Mackenzie (Nuremberg, Germany).