Re: [PATCH 1/2] qom: Clean up object_property_get_enum()'s error value

[Greg Kurz]

On Thu, 17 Sep 2020 14:55:39 +0200
Markus Armbruster <armbru@redhat.com> wrote:

> object_property_get_enum() is the only object_property_FOO() that is
> documented to return an undefined value on error.  It does no such
> thing, actually: it returns 0 on some errors, and -1 on others.
> 
> Needlessly complicated.  Always return -1 on error, and adjust the
> contract.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

>  include/qom/object.h       | 6 +++---
>  qom/object.c               | 6 +++---
>  tests/check-qom-proplist.c | 2 ++
>  3 files changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/include/qom/object.h b/include/qom/object.h
> index 056f67ab3b..f75547a3fe 100644
> --- a/include/qom/object.h
> +++ b/include/qom/object.h
> @@ -1687,9 +1687,9 @@ uint64_t object_property_get_uint(Object *obj, const 
> char *name,
>   * @typename: the name of the enum data type
>   * @errp: returns an error if this function fails
>   *
> - * Returns: the value of the property, converted to an integer, or
> - * undefined if an error occurs (including when the property value is not
> - * an enum).
> + * Returns: the value of the property, converted to an integer (which
> + * can't be negative), or -1 on error (including when the property
> + * value is not an enum).
>   */
>  int object_property_get_enum(Object *obj, const char *name,
>                               const char *typename, Error **errp);
> diff --git a/qom/object.c b/qom/object.c
> index 387efb25eb..cecad35b99 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -1564,21 +1564,21 @@ int object_property_get_enum(Object *obj, const char 
> *name,
>      EnumProperty *enumprop;
>  
>      if (prop == NULL) {
> -        return 0;
> +        return -1;
>      }
>  
>      if (!g_str_equal(prop->type, typename)) {
>          error_setg(errp, "Property %s on %s is not '%s' enum type",
>                     name, object_class_get_name(
>                         object_get_class(obj)), typename);
> -        return 0;
> +        return -1;
>      }
>  
>      enumprop = prop->opaque;
>  
>      str = object_property_get_str(obj, name, errp);
>      if (!str) {
> -        return 0;
> +        return -1;
>      }
>  
>      ret = qapi_enum_parse(enumprop->lookup, str, -1, errp);
> diff --git a/tests/check-qom-proplist.c b/tests/check-qom-proplist.c
> index 1571606c1c..1b76581980 100644
> --- a/tests/check-qom-proplist.c
> +++ b/tests/check-qom-proplist.c
> @@ -491,6 +491,7 @@ static void test_dummy_getenum(void)
>                                     "av",
>                                     "BadAnimal",
>                                     &err);
> +    g_assert(val == -1);
>      error_free_or_abort(&err);
>  
>      /* A non-enum property name */
> @@ -498,6 +499,7 @@ static void test_dummy_getenum(void)
>                                     "iv",
>                                     "DummyAnimal",
>                                     &err);
> +    g_assert(val == -1);
>      error_free_or_abort(&err);
>  
>      object_unparent(OBJECT(dobj));