Re: [RFC PATCH 4/4] qom: Warn when deprecated class property can be removed

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Jan 09, 2023 at 11:54:19PM +0100, Philippe Mathieu-Daudé wrote:
> Per docs/system/deprecated.rst, a deprecated feature can be
> removed after 2 releases. Since we commit when a class property
> is deprecated, we can warn when the deprecation period is over.
> 
> See also commit ef1f5b0a96 ("docs: clarify deprecation schedule").
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  qom/object.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/qom/object.c b/qom/object.c
> index 05b97cd424..cb829f1e44 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -17,6 +17,7 @@
>  #include "qom/object_interfaces.h"
>  #include "qemu/cutils.h"
>  #include "qemu/memalign.h"
> +#include "qemu/qemu-version.h"
>  #include "qapi/visitor.h"
>  #include "qapi/string-input-visitor.h"
>  #include "qapi/string-output-visitor.h"
> @@ -1300,6 +1301,12 @@ void object_class_property_deprecate(ObjectClass *klass,
>      ObjectProperty *prop = object_class_property_find(klass, name);
>  
>      assert(prop);
> +    if (qemu_version_delta_current(version_major, version_minor) <= 2) {
> +        warn_report_once("Property '%s.%s' has been deprecated in release"
> +                         " v%u.%u and can be removed.",
> +                         object_class_get_name(klass), name,
> +                         version_major, version_minor);
> +    }

IMHO this is not really appropriate. Removal of deprecated features
is a job for maintainers, but this is printing a message at users.

Maintainers have a record of deprecations in the docs that they can
periodically review to identify stuff that can now be deleted.


With regards,
Daniel
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