Re: [PATCH v9 1/9] machine: Use error handling when CPU type is checked

[Philippe Mathieu-Daudé]

On 4/12/23 01:47, Gavin Shan wrote:
> Functions that use an Error **errp parameter to return errors should
> not also report them to the user, because reporting is the caller's
> job. The principle is violated by machine_run_board_init() because
> it calls error_report(), error_printf(), and exit(1) when the machine
> doesn't support the requested CPU type.
>
> Clean this up by using error_setg() and error_append_hint() instead.
> No functional change, as the only caller passes &error_fatal.
>
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
> ---
> v9: Improved change log                                  (Markus)
> ---
>   hw/core/machine.c | 13 +++++++------
>   1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 0c17398141..bde7f4af6d 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -1466,15 +1466,16 @@ void machine_run_board_init(MachineState *machine, 
> const char *mem_path, Error *
>   
>           if (!machine_class->valid_cpu_types[i]) {
>               /* The user specified CPU is not valid */
> -            error_report("Invalid CPU type: %s", machine->cpu_type);
> -            error_printf("The valid types are: %s",
> -                         machine_class->valid_cpu_types[0]);
> +            error_setg(errp, "Invalid CPU type: %s", machine->cpu_type);
> +            error_append_hint(errp, "The valid types are: %s",
> +                              machine_class->valid_cpu_types[0]);
>               for (i = 1; machine_class->valid_cpu_types[i]; i++) {
> -                error_printf(", %s", machine_class->valid_cpu_types[i]);
> +                error_append_hint(errp, ", %s",
> +                                  machine_class->valid_cpu_types[i]);
>               }
> -            error_printf("\n");
>   
> -            exit(1);
> +            error_append_hint(&errp, "\n");

This doesn't build:

hw/core/machine.c:1488:31: error: incompatible pointer types passing 
'Error ***' (aka 'struct Error ***') to parameter of type 'Error *const 
*' (aka 'struct Error *const *'); remove & 
[-Werror,-Wincompatible-pointer-types]
            error_append_hint(&errp, "\n");
                              ^~~~~

> +            return;
>           }
>       }
>   

Squashing:
-- >8 --
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 021044aaaf..1898d1d1d7 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -1487,3 +1487,3 @@ void machine_run_board_init(MachineState *machine, 
const char *mem_path, Error *

-            error_append_hint(&errp, "\n");
+            error_append_hint(errp, "\n");
             return;
---