From d3309b9f7ebd2f803c018842573398167ea0f054 Mon Sep 17 00:00:00 2001
From: Paul Hauner <paul@paulhauner.com>
Date: Fri, 26 Apr 2019 17:27:39 +1000
Subject: [PATCH] Fix bug with bitfield tree hash caching

---
 eth2/utils/boolean-bitfield/src/lib.rs | 2 --
 eth2/utils/cached_tree_hash/src/lib.rs | 5 +++--
 eth2/utils/tree_hash_derive/src/lib.rs | 1 +
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/eth2/utils/boolean-bitfield/src/lib.rs b/eth2/utils/boolean-bitfield/src/lib.rs
index cdc58173f..c5fa590d6 100644
--- a/eth2/utils/boolean-bitfield/src/lib.rs
+++ b/eth2/utils/boolean-bitfield/src/lib.rs
@@ -287,14 +287,12 @@ mod tests {
         let mut hasher = cached_tree_hash::CachedTreeHasher::new(&original).unwrap();
 
         assert_eq!(hasher.tree_hash_root().unwrap(), original.tree_hash_root());
-        /*
 
         let modified = BooleanBitfield::from_bytes(&vec![2; 1][..]);
 
         hasher.update(&modified).unwrap();
 
         assert_eq!(hasher.tree_hash_root().unwrap(), modified.tree_hash_root());
-        */
     }
 
     #[test]
diff --git a/eth2/utils/cached_tree_hash/src/lib.rs b/eth2/utils/cached_tree_hash/src/lib.rs
index 24bbe0b07..0faf56ea2 100644
--- a/eth2/utils/cached_tree_hash/src/lib.rs
+++ b/eth2/utils/cached_tree_hash/src/lib.rs
@@ -125,7 +125,8 @@ macro_rules! cached_tree_hash_bytes_as_list {
             }
 
             fn tree_hash_cache_schema(&self, depth: usize) -> cached_tree_hash::BTreeSchema {
-                cached_tree_hash::impls::vec::produce_schema(&ssz::ssz_encode(self), depth)
+                let bytes = self.to_bytes();
+                cached_tree_hash::impls::vec::produce_schema(&bytes, depth)
             }
 
             fn update_tree_hash_cache(
@@ -145,7 +146,7 @@ macro_rules! cached_tree_hash_bytes_as_list {
                 cache.mix_in_length(new_overlay.chunk_range(), bytes.len())?;
 
                 // Skip an extra node to clear the length node.
-                cache.chunk_index = new_overlay.next_node() + 1;
+                cache.chunk_index += 1;
 
                 Ok(())
             }
diff --git a/eth2/utils/tree_hash_derive/src/lib.rs b/eth2/utils/tree_hash_derive/src/lib.rs
index 910417b81..fdfe1e5c0 100644
--- a/eth2/utils/tree_hash_derive/src/lib.rs
+++ b/eth2/utils/tree_hash_derive/src/lib.rs
@@ -88,6 +88,7 @@ pub fn subtree_derive(input: TokenStream) -> TokenStream {
             fn update_tree_hash_cache(&self, cache: &mut cached_tree_hash::TreeHashCache) -> Result<(), cached_tree_hash::Error> {
                 let overlay = cached_tree_hash::BTreeOverlay::new(self, cache.chunk_index, 0);
 
+
                 // Skip the chunk index to the first leaf node of this struct.
                 cache.chunk_index = overlay.first_leaf_node();
                 // Skip the overlay index to the first leaf node of this struct.