Add assert for non-NULL session

diff --git a/src/session.c b/src/session.c
index 99a02aa..e2c66d3 100644 (file)
--- a/src/session.c
+++ b/src/session.c
@@ -414,6 +414,7 @@ int session_set_watch(struct session *s, int what,
 
 void session_alert_watch(struct session *s, int what)
 {
+    assert(s);
     session_enter(s);
     if (s->watchlist[what].fun)
     {