Fix tango-controls#484

(Tango 9.3.1rc potential crash when an event is pushed at the same time as an
event (re)subscription occurs)

RELEASE_NOTES

@@ -6,6 +6,7 @@
 4. Fix some event compatibility issues with device server <= Tango 8 (#456)
 5. Fix event field in EventData structure passed to user's callback (broken in Tango 9.3.0 and 9.3.1)
 6. Fix attribute name in EventData structure passed to user's callback for Attribute Config events
+7. Fix a bug occurring when an event is pushed at the same time as an event (re)subscription occurs (#484)
 
 9.3.1
 =====

cppapi/server/zmqeventsupplier.cpp

@@ -1046,9 +1046,8 @@ void ZmqEventSupplier::push_event(DeviceImpl *device_impl,string event_type,
     string loc_obj_name(obj_name);
     transform(loc_obj_name.begin(), loc_obj_name.end(), loc_obj_name.begin(), ::tolower);
 
-    create_full_event_name(device_impl, event_type, loc_obj_name, intr_change);
-
-    ctr_event_name = ctr_event_name + local_event_type;
+    event_name = create_full_event_name(device_impl, event_type, loc_obj_name, intr_change);
+    ctr_event_name = create_full_event_name(device_impl, local_event_type, loc_obj_name, intr_change);
 
 //
 // Create zmq messages
@@ -1568,32 +1567,27 @@ ZmqEventSupplier::create_full_event_name(DeviceImpl *device_impl,
                                          const string &obj_name_lower,
                                          bool intr_change)
 {
-    event_name = fqdn_prefix;
+    string full_event_name = fqdn_prefix;
 
-    int size = event_name.size();
-    if (event_name[size - 1] == '#')
+    int size = full_event_name.size();
+    if (full_event_name[size - 1] == '#')
     {
-        event_name.erase(size - 1);
+        full_event_name.erase(size - 1);
     }
 
-    event_name = event_name + device_impl->get_name_lower();
+    full_event_name = full_event_name + device_impl->get_name_lower();
     if (intr_change == false)
     {
-        event_name = event_name + '/' + obj_name_lower;
+        full_event_name = full_event_name + '/' + obj_name_lower;
     }
     if (Util::_FileDb == true || Util::_UseDb == false)
     {
-        event_name = event_name + MODIFIER_DBASE_NO;
+        full_event_name = full_event_name + MODIFIER_DBASE_NO;
     }
-    event_name = event_name + '.';
-
-    //this field is in push_event
-    //TODO remove this field and replace with full_event_name
-    ctr_event_name = event_name;
-
-    event_name = event_name + event_type;
+    full_event_name = full_event_name + '.';
+    full_event_name = full_event_name + event_type;
 
-    return event_name;
+    return full_event_name;
 }
 
 //+------------------------------------------------------------------------------------------------------------------