Re: [PATCH v2 14/21] hw/core/qdev-properties: allow qdev properties accept flags

[Zhao Liu <zhao1.liu@intel.com>]

On Tue, Feb 10, 2026 at 09:56:08AM +0000, Daniel P. Berrangé wrote:
> Date: Tue, 10 Feb 2026 09:56:08 +0000
> From: "Daniel P. Berrangé" <berrange@redhat.com>
> Subject: Re: [PATCH v2 14/21] hw/core/qdev-properties: allow qdev
>  properties accept flags
> 
> On Tue, Feb 10, 2026 at 11:23:41AM +0800, Zhao Liu wrote:
> > Update qdev property interfaces (qdev_property_add_static() and
> > qdev_class_add_property()) to accept and pass 'ObjectPropertyFlags'.
> > This enables marking qdev properties with flags such as DEPRECATED or
> > INTERNAL.
> > 
> > To facilitate this at the definition level, extend the boolean and
> > uint8_t property macros (as the examples) to accept variable arguments
> > (VA_ARGS). This allows callers to optionally specify flags in the
> > property definition.
> > 
> > Example:
> > 
> > DEFINE_PROP_UINT8("version", IOAPICCommonState, version, IOAPIC_VER_DEF,
> >                   .flags = OBJECT_PROPERTY_DEPRECATED),
> 
> In other places where we track deprecation in QEMU, we have not used
> a boolean flag. Instead we have used a "const char *deprecation_note"
> internally, which lets us provide a user facing message, to be printed
> out in the warn_report, informing them what to do instead (either the
> feature is entirely removed, or there is a better alternative). IMHO
> we should be following the same pattern for properties, as it is much
> more user friendly than just printing a totally generic message
> "XXXX is deprecated, stop using it" 

Yes, rich deprecation hint is better. I think this still depends on
USER_SET - distinguish internal/external or not :-(.

Since when we mark a property as deprecated, its code remains in the
code tree, and internal calls should not trigger warnings. Deprecation
hints are intended to reminder external users.

Thanks,
Zhao