Update WFGraphNode

src/factory/WFGraphTask.cc

@@ -30,14 +30,18 @@ SubTask *WFGraphNode::done()
 		this->user_data = (void *)1;
 	}
 	else
+		delete this;
+
+	return series->pop();
+}
+
+WFGraphNode::~WFGraphNode()
+{
+	if (this->user_data)
 	{
 		for (WFGraphNode *node : this->successors)
 			node->WFCounterTask::count();
-
-		delete this;
 	}
-
-	return series->pop();
 }
 
 WFGraphNode& WFGraphTask::create_graph_node(SubTask *task)

src/factory/WFGraphTask.h

@@ -47,7 +47,7 @@ protected:
 
 protected:
 	WFGraphNode() : WFCounterTask(0, nullptr) { }
-	virtual ~WFGraphNode() { }
+	virtual ~WFGraphNode();
 	friend class WFGraphTask;
 };