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

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

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);
+    }
     prop->deprecation_reason = reason;
 }
 
-- 
2.38.1