bug#67764: 30.0.50; Opening image in eww no longer works

[Eli Zaretskii]

> Cc: 67764@debbugs.gnu.org
> From: Visuwesh <visuweshm@gmail.com>
> Date: Mon, 11 Dec 2023 17:10:01 +0530
> 
> >   emacs -Q
> >   M-: (eww "https://www.gnu.org/software/emacs/images/emacs.png";)
> >
> > On master it fails with "Wrong type argument: stringp, nil".
> > Bisect says 4254544 is the first bad commit.
> 
> Recent changes in shr-put-image didn't account for the possible nil
> value for ALT.  Attached patch fixes the issue on my end.
> 
> 
> >From f6d3fc0de572a1039e83df0389c1c7efce0ef0cf Mon Sep 17 00:00:00 2001
> From: Visuwesh <visuweshm@gmail.com>
> Date: Mon, 11 Dec 2023 17:09:03 +0530
> Subject: [PATCH] ; Fix shr-put-image with nil value for ALT
> 
> * lisp/net/shr.el (shr-put-image): Account for nil value for ALT.
> (Bug#6774)
> ---
>  lisp/net/shr.el | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lisp/net/shr.el b/lisp/net/shr.el
> index 9f030b4c743..19c52ac8802 100644
> --- a/lisp/net/shr.el
> +++ b/lisp/net/shr.el
> @@ -1137,7 +1137,7 @@ shr-put-image
>          (when image
>            ;; The trailing space can confuse shr-insert into not
>            ;; putting any space after inline images.
> -       (setq alt (string-trim alt))
> +       (setq alt (string-trim (or alt "*")))
>         ;; When inserting big-ish pictures, put them at the
>         ;; beginning of the line.
>         (let ((inline (shr--inline-image-p image)))

Thanks, but can we please avoid running a fixed string through
string-trim?

Also, I think the fallback on "*" deserves a comment to explain why
that is done.