Re: [PATCH] vl: Abort if multiple machines are registered as default

[Marc-André Lureau]

Hi

On Fri, Feb 7, 2020 at 12:03 PM Philippe Mathieu-Daudé
<address@hidden> wrote:
>
> It would be confusing to have multiple default machines.
> Abort if this ever occurs.
>
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> ---
>  vl.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/vl.c b/vl.c
> index 7dcb0879c4..da828188eb 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2354,6 +2354,8 @@ static MachineClass *machine_parse(const char *name, 
> GSList *machines)
>      GSList *el;
>
>      if (is_help_option(name)) {
> +        int default_count = 0;
> +
>          printf("Supported machines are:\n");
>          machines = g_slist_sort(machines, machine_class_cmp);
>          for (el = machines; el; el = el->next) {
> @@ -2364,6 +2366,11 @@ static MachineClass *machine_parse(const char *name, 
> GSList *machines)
>              printf("%-20s %s%s%s\n", mc->name, mc->desc,
>                     mc->is_default ? " (default)" : "",
>                     mc->deprecation_reason ? " (deprecated)" : "");
> +            default_count += !!mc->is_default;
> +        }
> +        if (default_count > 1) {
> +            error_printf("Multiple default machines available\n");
> +            abort();

looks ok

It's a build-time issue? If the user can't do anything about it, you
may simply have an assert(default_count <= 1) rather than a
human-friendly string, I think.

-- 
Marc-André Lureau