Including a tree from another directory which includes another tree fails

[asasine]

When you include from another directory, and that tree includes another tree, the BT factory throws the error XML_ERROR_FILE_NOT_FOUND.

Given these example trees and directory structure:

/
  tree_includes_tree_includes_same_directory.xml
  child/
    tree_includes_same_directory.xml
    tree_child_directory.xml

tree_includes_tree_includes_same_directory.xml

<root main_tree_to_execute = "IncludesTreeIncludesSameDirectory">
  <include path="child/tree_includes_same_directory.xml" />

  <BehaviorTree ID="IncludesTreeIncludesSameDirectory">
    <Sequence>
      <SubTree ID="IncudesSameDirectoryTree" />
      <AlwaysSuccess />
    </Sequence>
  </BehaviorTree>
</root>

child/tree_child_directory.xml

<root main_tree_to_execute = "ChildDirectoryTree">
  <BehaviorTree ID="ChildDirectoryTree">
    <AlwaysSuccess />
  </BehaviorTree>
</root>

child/tree_includes_same_directory.xml

<root main_tree_to_execute = "IncudesSameDirectoryTree">
  <include path="tree_child_directory.xml" />

  <BehaviorTree ID="IncudesSameDirectoryTree">
    <Sequence>
      <SubTree ID="ChildDirectoryTree" />
      <AlwaysSuccess />
    </Sequence>
  </BehaviorTree>
</root>

Loading the tree tree_includes_tree_includes_same_directory.xml using an absolute path, it throws the above error XML_ERROR_FILE_NOT_FOUND.

It does not seem to matter whether the second tree (tree_includes_same_directory.xml in this example) includes a third tree from the same directory, a parent directory, or a sibling directory; they all fail in the same way.

[asasine]

I was mistaken with the first examples I provided. After some testing, I've updated the title and examples to more clearly point out the issue I'm facing.

[asasine]

I think this comes from the way relative paths are handled when recursively including new XML files

---

When BehaviorTreeFactory::createTreeFromFile is called, XmlParser stores the absolute path of the directory of the tree file that into XmlParser._p->current_path

BehaviorTree.CPP/src/bt_factory.cpp

Lines 264 to 265 in 4b87a8e

	XMLParser parser(*this);
	parser.loadFromFile(file_path);

(which calls)

BehaviorTree.CPP/src/xml_parsing.cpp

Lines 110 to 111 in e6f241c

	filesystem::path file_path( filename );
	_p->current_path = file_path.parent_path().make_absolute();

Whenever an <include path="..."/ > is encountered while loading the tree, and that path is relative, it's combined with current_path

BehaviorTree.CPP/src/xml_parsing.cpp

Lines 168 to 171 in e6f241c

	if( !file_path.is_absolute() )
	{
	file_path = current_path / file_path;
	}

This works when a file (A) includes a file from a sibling directory (B), but breaks down when the included tree (B) includes anything else (C), from any directory. In that case, the parsing logic will take the path found in B and make it relative to A. not B.

---

Going back to the example I originally provided:

When tree_includes_tree_includes_same_directory.xml includes child/tree_includes_same_directory.xml, the XML parser will set current_path to "/", encounter <include path="tree_child_directory.xml" /> while parsing child/tree_includes_same_directory.xml, construct the file_path to be current_path / "tree_child_directory.xml" or "/tree_child_directory.xml", and fail to find a file at that path because one doesn't exist! The correct file path should have been "/child/tree_child_directory.xml" since that's the path relative to the file that was performing this level of inclusion.

---

I think the simplest solution is to make current_path relative to the file being loaded. Whenever loadDocImpl is recursively called during a file inclusion, current_path should update to the path of the included file.

BehaviorTree.CPP/src/xml_parsing.cpp

Line 176 in e6f241c

loadDocImpl(next_doc);