Fix for memory leak in Python target

core/src/main/java/org/lflang/federated/extensions/PythonExtension.java

@@ -144,7 +144,15 @@ protected void deserialize(
           value = action.getName();
           FedNativePythonSerialization pickler = new FedNativePythonSerialization();
           result.pr(pickler.generateNetworkDeserializerCode(value, null));
-          result.pr("lf_set(" + receiveRef + ", " + FedSerialization.deserializedVarName + ");\n");
+          // Use token to set ports and destructor
+          result.pr(
+              "lf_token_t* token = lf_new_token((void*)"
+                  + receiveRef
+                  + ", "
+                  + FedSerialization.deserializedVarName
+                  + ", 1);\n");
+          result.pr("lf_set_destructor(" + receiveRef + ", python_count_decrement);\n");
+          result.pr("lf_set_token(" + receiveRef + ", token);\n");
           break;
         }
       case PROTO:
@@ -179,6 +187,8 @@ protected void serializeAndSend(
           result.pr(pickler.generateNetworkSerializerCode(variableToSerialize, null));
           result.pr("size_t message_length = " + lengthExpression + ";");
           result.pr(sendingFunction + "(" + commonArgs + ", " + pointerExpression + ");\n");
+          // Decrease the reference count for serialized_pyobject
+          result.pr("Py_XDECREF(serialized_pyobject);\n");
           break;
         }
       case PROTO:

core/src/main/java/org/lflang/federated/serialization/FedNativePythonSerialization.java

@@ -89,7 +89,6 @@ public StringBuilder generateNetworkSerializerCode(String varName, String origin
     serializerCode.append(
         "    lf_print_error_and_exit(\"Could not serialize " + serializedVarName + ".\");\n");
     serializerCode.append("}\n");
-
     return serializerCode;
   }
 
@@ -106,7 +105,6 @@ public StringBuilder generateNetworkDeserializerCode(String varName, String targ
             + varName
             + "->token->length);\n");
     // Deserialize using Pickle
-    deserializerCode.append("Py_XINCREF(message_byte_array);\n");
     deserializerCode.append(
         "PyObject* "
             + deserializedVarName

core/src/main/java/org/lflang/generator/python/PythonDelayBodyGenerator.java

@@ -35,6 +35,7 @@ public String generateDelayBody(Action action, VarRef port) {
           "    lf_schedule_token(" + action.getName() + ", 0, " + ref + "->token);",
           "}");
     } else {
+      var value = "self->_lf_" + ref + "->value";
       return String.join(
           "\n",
           "// Create a token.",
@@ -44,9 +45,10 @@ public String generateDelayBody(Action action, VarRef port) {
           "#endif",
           "lf_token_t* t = _lf_new_token((token_type_t*)"
               + action.getName()
-              + ", self->_lf_"
-              + ref
-              + "->value, 1);",
+              + ", "
+              + value
+              + ", 1);",
+          "Py_INCREF(" + value + ");",
           "#if NUMBER_OF_WORKERS > 0",
           "lf_mutex_unlock(&mutex);",
           "#endif",

core/src/main/java/org/lflang/generator/python/PythonGenerator.java

@@ -574,7 +574,7 @@ private static String setUpMainTarget(
       boolean hasMain, String executableName, Stream<String> cSources) {
     return ("""
             set(CMAKE_POSITION_INDEPENDENT_CODE ON)
-            add_compile_definitions(_LF_GARBAGE_COLLECTED)
+            add_compile_definitions(_PYTHON_TARGET_ENABLED)
             add_subdirectory(core)
             set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR})
             set(LF_MAIN_TARGET <pyModuleName>)