reverted changing silent action name as JANI identifiers need to be non-empty

src/storm/storage/jani/Edge.h

@@ -13,6 +13,8 @@ namespace storm {
         
         class Edge {
         public:
+            Edge() = default;
+            
             Edge(uint64_t sourceLocationIndex, uint64_t actionIndex, boost::optional<storm::expressions::Expression> const& rate, storm::expressions::Expression const& guard, std::vector<EdgeDestination> destinations = {});
             
             /*!

src/storm/storage/jani/Model.cpp

@@ -14,7 +14,7 @@
 namespace storm {
     namespace jani {
         
-        const std::string Model::SILENT_ACTION_NAME = "__SILENT_ACTION__";
+        const std::string Model::SILENT_ACTION_NAME = "";
         const uint64_t Model::SILENT_ACTION_INDEX = 0;
         
         Model::Model() {

src/storm/storage/prism/ToJaniConverter.cpp

@@ -216,7 +216,12 @@ namespace storm {
                     }
                     
                     // Create the edge object so we can add transient assignments.
-                    storm::jani::Edge newEdge(onlyLocationIndex, janiModel.getActionIndex(command.getActionName()), rateExpression, command.getGuardExpression(), destinations);
+                    storm::jani::Edge newEdge;
+                    if (command.getActionName().empty()) {
+                        newEdge = storm::jani::Edge(onlyLocationIndex, storm::jani::Model::SILENT_ACTION_INDEX, rateExpression, command.getGuardExpression(), destinations);
+                    } else {
+                        newEdge = storm::jani::Edge(onlyLocationIndex, janiModel.getActionIndex(command.getActionName()), rateExpression, command.getGuardExpression(), destinations);
+                    }
                     
                     // Then add the transient assignments for the rewards. Note that we may do this only for the first
                     // module that has this action, so we remove the assignments from the global list of assignments