fix: handling already existing optional config groups (#267)

Co-authored-by: Tarek Chouaki <[email protected]>
Co-authored-by: Sebastian Hörl <[email protected]>

core/src/main/java/org/eqasim/core/simulation/EqasimConfigurator.java

@@ -172,7 +172,9 @@ protected void registerOptionalConfigGroup(ConfigGroup configGroup, Collection<A
 
     public void addOptionalConfigGroups(Config config) {
         for (ConfigGroup configGroup : optionalConfigGroups.values()) {
-            if (config.getModules().get(configGroup.getName()) != null) {
+            ConfigGroup existingConfigGroup = config.getModules().get(configGroup.getName());
+            // if a config group with the same name exist and is still a generic ConfigGroup instance, we replace it by the optional config group instance
+            if (existingConfigGroup != null && existingConfigGroup.getClass().equals(ConfigGroup.class)) {
                 config.addModule(configGroup);
             }
         }