[PATCH v4 3/3] vl: Abort if multiple machines are registered as default

[Philippe Mathieu-Daudé]

It would be confusing to have multiple default machines.
Abort if this ever occurs.

Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>
---
v2: Use assert() instead of human friendly message (Marc-André)
v3: Move the check to find_machine() (Michael)

Cc: Marc-André Lureau <marcandre.lur...@gmail.com>
Cc: Laurent Vivier <laur...@vivier.eu>
Cc: Michael S. Tsirkin <m...@redhat.com>
---
 vl.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/vl.c b/vl.c
index 7dcb0879c4..ebc203af0d 100644
--- a/vl.c
+++ b/vl.c
@@ -1184,16 +1184,18 @@ static MachineClass *find_machine(const char *name, 
GSList *machines)
 static MachineClass *find_default_machine(GSList *machines)
 {
     GSList *el;
+    MachineClass *default_machineclass = NULL;
 
     for (el = machines; el; el = el->next) {
         MachineClass *mc = el->data;
 
         if (mc->is_default) {
-            return mc;
+            assert(default_machineclass == NULL && "Multiple default 
machines");
+            default_machineclass = mc;
         }
     }
 
-    return NULL;
+    return default_machineclass;
 }
 
 static int machine_help_func(QemuOpts *opts, MachineState *machine)
-- 
2.21.1