qom: Add error handler for object_property_print()

Avoid the caller of object_property_print() leaking string
argument's memory, such as qdev_print_props() when
encounter errors.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Signed-off-by: NAndreas Färber <afaerber@suse.de>

qom/object.c

@@ -1010,11 +1010,19 @@ char *object_property_print(Object *obj, const char *name, bool human,
                             Error **errp)
 {
     StringOutputVisitor *mo;
-    char *string;
+    char *string = NULL;
+    Error *local_err = NULL;
 
     mo = string_output_visitor_new(human);
-    object_property_get(obj, string_output_get_visitor(mo), name, errp);
+    object_property_get(obj, string_output_get_visitor(mo), name, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        goto out;
+    }
+
     string = string_output_get_string(mo);
+
+out:
     string_output_visitor_cleanup(mo);
     return string;
 }