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

[Gavin Shan <gshan@redhat.com>]

On 1/5/24 21:00, Philippe Mathieu-Daudé wrote:
> 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");
>                                ^~~~~
> 

Yes, &errp should have been errp. The problematic code was carried from
previous revisions and has been corrected by PATCH[2/9]. It's how I missed
the building error. Thanks for fixing it up!

Thanks,
Gavin

>> +            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;
> ---
>