[Qemu-devel] [PATCH v7 20/31] spapr_drc: Expose 'null' in qom-get when there is no fdt

[Eric Blake <eblake@redhat.com>]

Now that the QMP output visitor supports an explicit null
output, we should utilize it to make it easier to diagnose
the difference between a missing fdt vs. a present-but-empty
one.

(Note that this reverts the behavior of commit ab8bf1d, taking
us back to the behavior of commit 1d10b44; but that this time,
the change is intentional and not an accidental side-effect.)

Signed-off-by: Eric Blake <eblake@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>

---
v7: new patch, based on discussion about spapr_drc.c
---
 hw/ppc/spapr_drc.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index dcce563..0c675ff 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -259,11 +259,7 @@ static void prop_get_fdt(Object *obj, Visitor *v, void *opaque,
     void *fdt;

     if (!drc->fdt) {
-        visit_start_struct(v, NULL, 0, name, &err);
-        if (!err) {
-            visit_end_struct(v, &err);
-        }
-        error_propagate(errp, err);
+        visit_type_null(v, NULL, errp);
         return;
     }

-- 
2.4.3