Fixed a crash occuring when you didn't initialized a Tree object (#20)

Author: Masadow

include/behaviortree_cpp/xml_parsing.h

@@ -37,9 +37,23 @@ struct Tree
 {
     TreeNode* root_node;
     std::vector<TreeNode::Ptr> nodes;
+
+    Tree() : root_node(nullptr)
+    {
+        
+    }
+
+    Tree(TreeNode* root_node, std::vector<TreeNode::Ptr> nodes)
+        : root_node(root_node), nodes(nodes)
+    {
+
+    }
+
     ~Tree()
     {
-        haltAllActions(root_node);
+        if (root_node) {
+            haltAllActions(root_node);
+        }
     }
 };
 

src/xml_parsing.cpp

@@ -543,7 +543,7 @@ Tree buildTreeFromText(const BehaviorTreeFactory& factory, const std::string& te
     std::vector<TreeNode::Ptr> nodes;
     auto root = parser.instantiateTree(nodes);
     assignBlackboardToEntireTree(root.get(), blackboard);
-    return {root.get(), nodes};
+    return Tree(root.get(), nodes);
 }
 
 Tree buildTreeFromFile(const BehaviorTreeFactory& factory, const std::string& filename,
@@ -555,6 +555,6 @@ Tree buildTreeFromFile(const BehaviorTreeFactory& factory, const std::string& fi
     std::vector<TreeNode::Ptr> nodes;
     auto root = parser.instantiateTree(nodes);
     assignBlackboardToEntireTree(root.get(), blackboard);
-    return {root.get(), nodes};
+    return Tree(root.get(), nodes);
 }
 }