[PULL 10/13] qom: Improve {qom, device}-list-properties error messages

[Markus Armbruster <armbru@redhat.com>]

device-list-properties reports

    Parameter 'typename' expects device

when @typename exists, but isn't a TYPE_DEVICE.  Improve this to

    Parameter 'typename' expects a non-abstract device type

qom-list-properties reports

    Parameter 'typename' expects object

when @typename exists, but isn't a TYPE_OBJECT.  Improve this to

    Parameter 'typename' expects a QOM type

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201113082626.2725812-10-armbru@redhat.com>
---
 qom/qom-qmp-cmds.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/qom/qom-qmp-cmds.c b/qom/qom-qmp-cmds.c
index 310ab2d048..2dd233f293 100644
--- a/qom/qom-qmp-cmds.c
+++ b/qom/qom-qmp-cmds.c
@@ -138,15 +138,10 @@ ObjectPropertyInfoList *qmp_device_list_properties(const char *typename,
         return NULL;
     }
 
-    klass = object_class_dynamic_cast(klass, TYPE_DEVICE);
-    if (klass == NULL) {
-        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "typename", TYPE_DEVICE);
-        return NULL;
-    }
-
-    if (object_class_is_abstract(klass)) {
+    if (!object_class_dynamic_cast(klass, TYPE_DEVICE)
+        || object_class_is_abstract(klass)) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "typename",
-                   "non-abstract device type");
+                   "a non-abstract device type");
         return NULL;
     }
 
@@ -208,9 +203,9 @@ ObjectPropertyInfoList *qmp_qom_list_properties(const char *typename,
         return NULL;
     }
 
-    klass = object_class_dynamic_cast(klass, TYPE_OBJECT);
-    if (klass == NULL) {
-        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "typename", TYPE_OBJECT);
+    if (!object_class_dynamic_cast(klass, TYPE_OBJECT)) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "typename",
+                   "a QOM type");
         return NULL;
     }
 
-- 
2.26.2