fixed incorrect parsing of jani constants

src/storm-parsers/parser/JaniParser.cpp

@@ -124,14 +124,18 @@ namespace storm {
             Scope scope(name);
             
             // Parse constants
-            size_t constantsCount = parsedStructure.count("constants");
             ConstantsMap constants;
             scope.constants = &constants;
+            size_t constantsCount = parsedStructure.count("constants");
             STORM_LOG_THROW(constantsCount < 2, storm::exceptions::InvalidJaniException, "Constant-declarations can be given at most once.");
             if (constantsCount == 1) {
                 for (auto const &constStructure : parsedStructure.at("constants")) {
                     std::shared_ptr<storm::jani::Constant> constant = parseConstant(constStructure, scope.refine("constants[" + std::to_string(constants.size()) + "]"));
-                    constants.emplace(constant->getName(), &model.addConstant(*constant));
+                    model.addConstant(*constant);
+                }
+                // Insert references after adding all constants to make sure that they remain valid
+                for (auto const& constant : model.getConstants()) {
+                    constants.emplace(constant.getName(), &constant);
                 }
             }
             

src/storm/storage/jani/Model.cpp

@@ -604,12 +604,12 @@ namespace storm {
             return nonsilentActionIndices;
         }
         
-        Constant const& Model::addConstant(Constant const& constant) {
+        void Model::addConstant(Constant const& constant) {
             auto it = constantToIndex.find(constant.getName());
             STORM_LOG_THROW(it == constantToIndex.end(), storm::exceptions::WrongFormatException, "Cannot add constant with name '" << constant.getName() << "', because a constant with that name already exists.");
             constantToIndex.emplace(constant.getName(), constants.size());
             constants.push_back(constant);
-            return constants.back();
+            // Note that we should not return a reference to the inserted constant as it might get invalidated when more constants are added.
         }
         
         bool Model::hasConstant(std::string const& name) const {

src/storm/storage/jani/Model.h

@@ -157,7 +157,7 @@ namespace storm {
             /*!
              * Adds the given constant to the model.
              */
-            Constant const& addConstant(Constant const& constant);
+            void addConstant(Constant const& constant);
             
             /*!
              * Retrieves whether the model has a constant with the given name.
@@ -176,6 +176,7 @@ namespace storm {
 
             /*!
              * Retrieves the constant with the given name (if any).
+             * @note the reference to the constant is invalidated whenever a new constant is added.
              */
             Constant const& getConstant(std::string const& name) const;