import maya.cmds as cmds


def get_inbetween_nodes(source_node, target_node):
    all_nodes = set()
    nodes = cmds.listConnections(source_node, source=False, destination=True)

    if nodes is None:
        return all_nodes

    for node in nodes:
        if node == target_node:
            continue
        all_nodes.add(node)
        all_nodes = all_nodes | get_inbetween_nodes(node, target_node)

    return all_nodes


def graph_inbetween_nodes(source_node, target_node):
    inbetween_nodes = list(get_inbetween_nodes(source_node, target_node))
    nodes = [source_node, target_node] + inbetween_nodes
    cmds.select(nodes, replace=True)

    for node in nodes:
        cmds.nodeEditor("nodeEditorPanel1NodeEditorEd", edit=True, addNode=node)


def graph_between_selection():
    sel = cmds.ls(sl=True)
    if len(sel) != 2:
        raise ValueError("You should have 2 nodes selected, not {}".format(len(sel)))
    try:
        graph_inbetween_nodes(sel[0], sel[1])
    except RuntimeError:
        try:
            graph_inbetween_nodes(sel[1], sel[0])
        except RuntimeError as e:
            if (
                str(e)
                == "maximum recursion depth exceeded while calling a Python object"
            ):
                cmds.warning("No nodes found between {} and {}".format(sel[0], sel[1]))


if __name__ == "__main__":
    graph_between_selection()