forest: clone correctly

Now the forest can detect if a node is packed or cloned, and correctly
clones a node in those circumstances.  But it still needs to be
tested.

1 files changed, 3 insertions, 0 deletions

diff --git a/graph/src/builder.rs b/graph/src/builder.rs
index b04e7f6..c5f9252 100644
--- a/graph/src/builder.rs
+++ b/graph/src/builder.rs
@@ -82,6 +82,9 @@ pub trait BuilderMut {
     /// Add an edge from the source to the target.
     fn add_edge(&mut self, source: usize, target: usize, label: Self::Label) -> Result<(), Error>;
 
+    /// Set the label of an existing node to a new label.
+    fn set_label(&mut self, node_id: usize, label: Self::Label) -> Result<(), Error>;
+
     /// Remove an edge from the source to the target.
     ///
     /// Since some graphs are labelled, the users are allowed to pass