Handle setModule(NULL) more safely.

If module_name is null, we can't do much of anything - we don't have a
protocol ID, so we don't have a protocol.

Change-Id: I42c2fa4b47e39d7ac122c60be91b5d408bf30a1d
Reviewed-on: https://code.wireshark.org/review/9569
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 3 insertions, 6 deletions

diff --git a/ui/qt/protocol_preferences_menu.cpp b/ui/qt/protocol_preferences_menu.cpp
index fca9e22909..81fd630a71 100644
--- a/ui/qt/protocol_preferences_menu.cpp
+++ b/ui/qt/protocol_preferences_menu.cpp
@@ -184,12 +184,9 @@ void ProtocolPreferencesMenu::setModule(const char *module_name)
     module_name_.clear();
     module_ = NULL;
 
-    if (module_name) {
-        proto_id = proto_get_id_by_filter_name(module_name);
-        protocol = find_protocol_by_id(proto_id);
-    }
-
-    if (proto_id < 0 || !protocol) {
+    if (!module_name ||
+        (proto_id = proto_get_id_by_filter_name(module_name)) < 0 ||
+        !(protocol = find_protocol_by_id(proto_id))) {
         action = addAction(tr("No protocol preferences available"));
         action->setDisabled(true);
         return;