bug#66192: 30.0.50; lisp/buttons.el (push-button) fails to handle the <return> action on gui emacs

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Madhu <enometh@meer.net> writes:

> * commit a496509cedb17109d0e6297a74e2ff8ed526333c
> |Commit:     Po Lu <luangruo@yahoo.com>
> |CommitDate: Thu Jan 19 22:19:06 2023 +0800
>
> Introduced a change to lisp/button.el:(push-button) which causes the
> following recipe to fail. Consider a buffer with the following
> contents:
>
> ```
> ;;text-button
>
> (defvar-keymap my-button-map :parent button-map "<return>" 'push-button)
> (setq $but (make-text-button 1 10
> 			     'action #'(lambda(b) (message "push-button %S" b))
> 			     'keymap my-button-map))
> ```
>
> evaluating the buffer sets up a text button in the first line. In a gui
> emacs Hitting RET on the button fails with an error:
> 	"push-button: Wrong type argument: listp, return".
>
> The following patch fixes it for me but maybe there is some other issue?
>
>>From e69be9cf0af72c5fcda8cda05b50a556741009b2 Mon Sep 17 00:00:00 2001
> From: Madhu <enometh@net.meer>
> Date: Mon, 25 Sep 2023 20:20:05 +0530
> Subject: [PATCH] lisp/button.el: (push-button): handle kbd <return>
>
> ---
>  lisp/button.el | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lisp/button.el b/lisp/button.el
> index b01595943fc..0e98ec722d9 100644
> --- a/lisp/button.el
> +++ b/lisp/button.el
> @@ -492,7 +492,7 @@ push-button
>  	    (if str-button
>  	        ;; mode-line, header-line, or display string event.
>  	        (button-activate str t)
> -              (if (eq (car pos) 'touchscreen-down)
> +              (if (and (listp pos) (eq (car pos) 'touchscreen-down))
>                    ;; If touch-screen-track tap returns nil, then the
>                    ;; tap was cancelled.
>                    (when (touch-screen-track-tap pos)

Thanks, but I elected to fix this differently.  Please test.