bug#66326: 29.1.50; There should be a way to promote warnings to errors

[Eli Zaretskii <eliz@gnu.org>]

> From: Spencer Baugh <sbaugh@janestreet.com>
> Date: Tue, 03 Oct 2023 14:39:02 -0400
> 
> +(defcustom warning-to-error-types nil
> +  "List of warning types to signal as an error instead.
> +If any element of this list matches the TYPE argument to `display-warning',
> +an error is signaled instead of logging a warning.
   ^^^^^^^^^^^^^^^^^^^^
Passive voice alert!

>  (defun display-warning (type message &optional level buffer-name)
>    "Display a warning message, MESSAGE.
> @@ -263,105 +278,109 @@ display-warning
>  disable automatic display of the warning or disable the warning
>  entirely by setting `warning-suppress-types' or
>  `warning-suppress-log-types' on their behalf."
> -  (if (not (or after-init-time noninteractive (daemonp)))
> -      ;; Ensure warnings that happen early in the startup sequence
> -      ;; are visible when startup completes (bug#20792).
> -      (delay-warning type message level buffer-name)
> -    (unless level
> -      (setq level :warning))
> -    (unless buffer-name
> -      (setq buffer-name "*Warnings*"))
> +  (unless level
> +    (setq level :warning))
> +  (unless buffer-name
> +    (setq buffer-name "*Warnings*"))
> +  (cond
> +   ((< (warning-numeric-level level)
> +       (warning-numeric-level warning-minimum-log-level)))
> +   ((warning-suppress-p type warning-suppress-log-types))
> +   ((warning-suppress-p type warning-to-error-types)
> +    (warning-to-error type message level))
> +   ((not (or after-init-time noninteractive (daemonp)))
> +    ;; Ensure warnings that happen early in the startup sequence
> +    ;; are visible when startup completes (bug#20792).
> +    (delay-warning type message level buffer-name))
> +   (t

AFAICT, this reorders parts of the evaluation, and thus changes the
semantics/behavior.  Please try to keep the order of the evaluation
the same as it was, to avoid unintended consequences.  (It will also
make the patch review easier.)

Thanks.