From 4306ec3e05a57950e7681d88316b4c29b1a53ce6 Mon Sep 17 00:00:00 2001
From: Pepper Lebeck-Jobe <eljobe@gmail.com>
Date: Wed, 22 May 2024 13:22:00 +0200
Subject: [PATCH] Handle the empty leaves case.

During a clone of an empty Merkle tree, there was an index out of
bounds error.
---
 arbitrator/prover/src/merkle.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arbitrator/prover/src/merkle.rs b/arbitrator/prover/src/merkle.rs
index be1eef8b69..005d3dae16 100644
--- a/arbitrator/prover/src/merkle.rs
+++ b/arbitrator/prover/src/merkle.rs
@@ -223,7 +223,12 @@ fn new_layer(ty: MerkleType, layer: &Vec<Bytes32>, empty_hash: &'static Bytes32)
 
 impl Clone for Merkle {
     fn clone(&self) -> Self {
-        Merkle::new_advanced(self.ty, self.layers.lock().data[0].clone(), self.min_depth)
+        let leaves = if self.layers.lock().data.is_empty() {
+            vec![]
+        } else {
+            self.layers.lock().data[0].clone()
+        };
+        Merkle::new_advanced(self.ty, leaves, self.min_depth)
     }
 }