From d6f0490993bcf88f786c5271091aa9a84ff2fe69 Mon Sep 17 00:00:00 2001
From: Charlie Little <cwlittle@utexas.edu>
Date: Mon, 21 Oct 2024 19:44:16 -0500
Subject: [PATCH 1/5] Support u16::MAX length keys

---
 src/proofs/encoding.rs | 10 +++++-----
 src/tree/kv.rs         |  6 +++++-
 src/tree/link.rs       | 10 ++++++++--
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/src/proofs/encoding.rs b/src/proofs/encoding.rs
index 9f33f245..aa8a3dcd 100644
--- a/src/proofs/encoding.rs
+++ b/src/proofs/encoding.rs
@@ -18,10 +18,10 @@ impl Encode for Op {
                 dest.write_all(kv_hash)?;
             }
             Op::Push(Node::KV(key, value)) => {
-                debug_assert!(key.len() < 256);
+                debug_assert!(key.len() < 65536);
                 debug_assert!(value.len() < 65536);
-
-                dest.write_all(&[0x03, key.len() as u8])?;
+                dest.write_all(&[0x03])?;
+                (key.len() as u16).encode_into(dest)?;
                 dest.write_all(key)?;
                 (value.len() as u16).encode_into(dest)?;
                 dest.write_all(value)?;
@@ -36,7 +36,7 @@ impl Encode for Op {
         Ok(match self {
             Op::Push(Node::Hash(_)) => 1 + HASH_LENGTH,
             Op::Push(Node::KVHash(_)) => 1 + HASH_LENGTH,
-            Op::Push(Node::KV(key, value)) => 4 + key.len() + value.len(),
+            Op::Push(Node::KV(key, value)) => 5 + key.len() + value.len(),
             Op::Parent => 1,
             Op::Child => 1,
         })
@@ -59,7 +59,7 @@ impl Decode for Op {
                 Op::Push(Node::KVHash(hash))
             }
             0x03 => {
-                let key_len: u8 = Decode::decode(&mut input)?;
+                let key_len: u16 = Decode::decode(&mut input)?;
                 let mut key = vec![0; key_len as usize];
                 input.read_exact(key.as_mut_slice())?;
 
diff --git a/src/tree/kv.rs b/src/tree/kv.rs
index 94fef4e0..213cb7f5 100644
--- a/src/tree/kv.rs
+++ b/src/tree/kv.rs
@@ -75,7 +75,11 @@ impl Encode for KV {
 
     #[inline]
     fn encoding_length(&self) -> Result<usize> {
-        debug_assert!(self.key().len() < 256, "Key length must be less than 256");
+        debug_assert!(
+            self.key().len() < 65535,
+            "Key length must be less than 65535"
+        );
+
         Ok(HASH_LENGTH + self.value.len())
     }
 }
diff --git a/src/tree/link.rs b/src/tree/link.rs
index 67c972c0..42aee4c7 100644
--- a/src/tree/link.rs
+++ b/src/tree/link.rs
@@ -221,7 +221,10 @@ impl Encode for Link {
             Link::Modified { .. } => panic!("No encoding for Link::Modified"),
         };
 
-        debug_assert!(key.len() < 256, "Key length must be less than 256");
+        debug_assert!(
+            self.key().len() < 65535,
+            "Key length must be less than 65535"
+        );
 
         out.write_all(&[key.len() as u8])?;
         out.write_all(key)?;
@@ -235,7 +238,10 @@ impl Encode for Link {
 
     #[inline]
     fn encoding_length(&self) -> Result<usize> {
-        debug_assert!(self.key().len() < 256, "Key length must be less than 256");
+        debug_assert!(
+            self.key().len() < 65535,
+            "Key length must be less than 65535"
+        );
 
         Ok(match self {
             Link::Reference { key, .. } => 1 + key.len() + 32 + 2,

From eb64d322328e7fd0e21a905640f5f5fd0dabab6e Mon Sep 17 00:00:00 2001
From: Charlie Little <cwlittle@utexas.edu>
Date: Mon, 21 Oct 2024 20:03:02 -0500
Subject: [PATCH 2/5] Update tests

---
 src/merk/chunks.rs      | 49 +++++++++++++++++++++--------------------
 src/proofs/encoding.rs  |  8 +++----
 src/proofs/query/mod.rs | 10 ++++-----
 src/tree/link.rs        |  2 +-
 4 files changed, 35 insertions(+), 34 deletions(-)

diff --git a/src/merk/chunks.rs b/src/merk/chunks.rs
index effcc0ec..a8b6f555 100644
--- a/src/merk/chunks.rs
+++ b/src/merk/chunks.rs
@@ -311,70 +311,71 @@ mod tests {
         assert_eq!(
             chunk,
             vec![
-                3, 8, 0, 0, 0, 0, 0, 0, 0, 18, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 18, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 3, 8, 0, 0, 0, 0, 0, 0, 0, 19, 0, 60, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 19, 0, 60, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 123, 16, 3, 8, 0, 0, 0, 0, 0, 0, 0, 20, 0, 60, 123, 123,
-                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 123, 123, 123, 123, 16, 3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 20, 0,
+                60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 17, 3, 8, 0, 0, 0, 0, 0, 0, 0,
-                21, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 17, 3, 0, 8, 0, 0, 0,
+                0, 0, 0, 0, 21, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 16, 3, 8, 0,
-                0, 0, 0, 0, 0, 0, 22, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 16,
+                3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 22, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 3, 8, 0, 0, 0, 0, 0, 0, 0, 23, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 23, 0, 60, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 16, 3, 8, 0, 0, 0, 0, 0, 0, 0, 24, 0, 60, 123, 123, 123, 123,
+                123, 123, 123, 123, 123, 123, 123, 123, 16, 3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 24, 0,
+                60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 17, 17, 3, 0, 8, 0, 0,
+                0, 0, 0, 0, 0, 25, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 123, 123, 123, 17, 17, 3, 8, 0, 0, 0, 0, 0, 0, 0, 25, 0,
-                60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 16, 3, 8, 0, 0, 0, 0,
-                0, 0, 0, 26, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 16, 3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 26, 0, 60, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 3,
-                8, 0, 0, 0, 0, 0, 0, 0, 27, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 123, 123, 3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 27, 0, 60, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 16, 3, 8, 0, 0, 0, 0, 0, 0, 0, 28, 0, 60, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 16, 3, 0, 8, 0, 0, 0, 0, 0, 0, 0,
+                28, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 123, 123, 17, 3, 8, 0, 0, 0, 0, 0, 0, 0, 29, 0, 60, 123,
+                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 17, 3, 0, 8,
+                0, 0, 0, 0, 0, 0, 0, 29, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 16, 3, 8, 0, 0, 0, 0, 0, 0,
-                0, 30, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 16, 3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 30, 0, 60, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 3, 8, 0, 0,
-                0, 0, 0, 0, 0, 31, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 123, 123, 123, 3, 0, 8, 0, 0, 0, 0, 0, 0, 0, 31, 0, 60, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 16, 3, 8, 0, 0, 0, 0, 0, 0, 0, 32, 0, 60, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
+                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 16, 3, 0, 8, 0, 0, 0, 0, 0,
+                0, 0, 32, 0, 60, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
                 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123,
-                123, 123, 123, 123, 123, 17, 17, 17
+                123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 123, 17, 17,
+                17
             ]
         );
     }
diff --git a/src/proofs/encoding.rs b/src/proofs/encoding.rs
index aa8a3dcd..1a83d206 100644
--- a/src/proofs/encoding.rs
+++ b/src/proofs/encoding.rs
@@ -173,11 +173,11 @@ mod test {
     #[test]
     fn encode_push_kv() {
         let op = Op::Push(Node::KV(vec![1, 2, 3], vec![4, 5, 6]));
-        assert_eq!(op.encoding_length(), 10);
+        assert_eq!(op.encoding_length(), 11);
 
         let mut bytes = vec![];
         op.encode_into(&mut bytes).unwrap();
-        assert_eq!(bytes, vec![0x03, 3, 1, 2, 3, 0, 3, 4, 5, 6]);
+        assert_eq!(bytes, vec![0x03, 0, 3, 1, 2, 3, 0, 3, 4, 5, 6]);
     }
 
     #[test]
@@ -203,7 +203,7 @@ mod test {
     #[test]
     #[should_panic]
     fn encode_push_kv_long_key() {
-        let op = Op::Push(Node::KV(vec![123; 300], vec![4, 5, 6]));
+        let op = Op::Push(Node::KV(vec![123; 70_000], vec![4, 5, 6]));
         let mut bytes = vec![];
         op.encode_into(&mut bytes).unwrap();
     }
@@ -230,7 +230,7 @@ mod test {
 
     #[test]
     fn decode_push_kv() {
-        let bytes = [0x03, 3, 1, 2, 3, 0, 3, 4, 5, 6];
+        let bytes = [0x03, 0, 3, 1, 2, 3, 0, 3, 4, 5, 6];
         let op = Op::decode(&bytes[..]).expect("decode failed");
         assert_eq!(op, Op::Push(Node::KV(vec![1, 2, 3], vec![4, 5, 6])));
     }
diff --git a/src/proofs/query/mod.rs b/src/proofs/query/mod.rs
index 2dc7e735..11808910 100644
--- a/src/proofs/query/mod.rs
+++ b/src/proofs/query/mod.rs
@@ -932,11 +932,11 @@ mod test {
         assert_eq!(
             bytes,
             vec![
-                3, 1, 1, 0, 1, 1, 3, 1, 2, 0, 1, 2, 16, 3, 1, 3, 0, 1, 3, 3, 1, 4, 0, 1, 4, 16, 17,
-                2, 169, 4, 73, 65, 62, 49, 160, 159, 37, 166, 195, 249, 63, 31, 23, 11, 169, 0, 24,
-                104, 179, 211, 218, 38, 108, 129, 117, 232, 65, 101, 194, 157, 16, 1, 148, 241,
-                151, 144, 247, 220, 92, 79, 70, 252, 168, 222, 27, 218, 53, 156, 0, 136, 161, 107,
-                83, 78, 150, 246, 51, 230, 164, 248, 17, 30, 147, 91, 17
+                3, 0, 1, 1, 0, 1, 1, 3, 0, 1, 2, 0, 1, 2, 16, 3, 0, 1, 3, 0, 1, 3, 3, 0, 1, 4, 0,
+                1, 4, 16, 17, 2, 169, 4, 73, 65, 62, 49, 160, 159, 37, 166, 195, 249, 63, 31, 23,
+                11, 169, 0, 24, 104, 179, 211, 218, 38, 108, 129, 117, 232, 65, 101, 194, 157, 16,
+                1, 148, 241, 151, 144, 247, 220, 92, 79, 70, 252, 168, 222, 27, 218, 53, 156, 0,
+                136, 161, 107, 83, 78, 150, 246, 51, 230, 164, 248, 17, 30, 147, 91, 17
             ]
         );
 
diff --git a/src/tree/link.rs b/src/tree/link.rs
index 42aee4c7..e07cdf18 100644
--- a/src/tree/link.rs
+++ b/src/tree/link.rs
@@ -467,7 +467,7 @@ mod test {
     #[should_panic]
     fn encode_link_long_key() {
         let link = Link::Reference {
-            key: vec![123; 300],
+            key: vec![123; 70_000],
             child_heights: (123, 124),
             hash: [55; 32],
         };

From 9b55314c15dd3b04ec3043a0b9dd3c6f6039fbe8 Mon Sep 17 00:00:00 2001
From: Matt Bell <mappum@gmail.com>
Date: Fri, 1 Nov 2024 16:25:50 -0500
Subject: [PATCH 3/5] Fix off-by-one in key length assertions

---
 src/tree/kv.rs   |  4 ++--
 src/tree/link.rs | 10 +++++-----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/tree/kv.rs b/src/tree/kv.rs
index 213cb7f5..42382c9f 100644
--- a/src/tree/kv.rs
+++ b/src/tree/kv.rs
@@ -76,8 +76,8 @@ impl Encode for KV {
     #[inline]
     fn encoding_length(&self) -> Result<usize> {
         debug_assert!(
-            self.key().len() < 65535,
-            "Key length must be less than 65535"
+            self.key().len() < 65536,
+            "Key length must be less than 65536"
         );
 
         Ok(HASH_LENGTH + self.value.len())
diff --git a/src/tree/link.rs b/src/tree/link.rs
index e07cdf18..8a305f4c 100644
--- a/src/tree/link.rs
+++ b/src/tree/link.rs
@@ -222,8 +222,8 @@ impl Encode for Link {
         };
 
         debug_assert!(
-            self.key().len() < 65535,
-            "Key length must be less than 65535"
+            self.key().len() < 65536,
+            "Key length must be less than 65536"
         );
 
         out.write_all(&[key.len() as u8])?;
@@ -239,8 +239,8 @@ impl Encode for Link {
     #[inline]
     fn encoding_length(&self) -> Result<usize> {
         debug_assert!(
-            self.key().len() < 65535,
-            "Key length must be less than 65535"
+            self.key().len() < 65536,
+            "Key length must be less than 65536"
         );
 
         Ok(match self {
@@ -464,7 +464,7 @@ mod test {
     }
 
     #[test]
-    #[should_panic]
+    #[should_panic = "Key length must be less than 65536"]
     fn encode_link_long_key() {
         let link = Link::Reference {
             key: vec![123; 70_000],

From 27bca231bc20c41704bd1e9b81deba7f86ccff53 Mon Sep 17 00:00:00 2001
From: Matt Bell <mappum@gmail.com>
Date: Fri, 1 Nov 2024 16:27:44 -0500
Subject: [PATCH 4/5] Use big-endian u16 instead of u8 for key length in
 storage encoding

---
 src/tree/link.rs | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/tree/link.rs b/src/tree/link.rs
index 8a305f4c..8ce8dde0 100644
--- a/src/tree/link.rs
+++ b/src/tree/link.rs
@@ -226,7 +226,7 @@ impl Encode for Link {
             "Key length must be less than 65536"
         );
 
-        out.write_all(&[key.len() as u8])?;
+        out.write_all(&(key.len() as u16).to_be_bytes())?;
         out.write_all(key)?;
 
         out.write_all(hash)?;
@@ -285,7 +285,7 @@ impl Decode for Link {
             ref mut child_heights,
         } = self
         {
-            let length = read_u8(&mut input)? as usize;
+            let length = read_u16(&mut input)? as usize;
 
             key.resize(length, 0);
             input.read_exact(key.as_mut())?;
@@ -304,6 +304,13 @@ impl Decode for Link {
 
 impl Terminated for Link {}
 
+#[inline]
+fn read_u16<R: Read>(mut input: R) -> Result<u16> {
+    let mut length = [0, 0];
+    input.read_exact(length.as_mut())?;
+    Ok(u16::from_be_bytes(length))
+}
+
 #[inline]
 fn read_u8<R: Read>(mut input: R) -> Result<u8> {
     let mut length = [0];

From bf2e0caf1264508973b736e7be33429b43eb83e3 Mon Sep 17 00:00:00 2001
From: Matt Bell <mappum@gmail.com>
Date: Fri, 1 Nov 2024 16:27:59 -0500
Subject: [PATCH 5/5] Add long key length test

---
 src/tree/encoding.rs |  8 ++++----
 src/tree/kv.rs       |  1 +
 src/tree/link.rs     | 21 ++++++++++++++++++---
 src/tree/mod.rs      |  4 ++--
 4 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/src/tree/encoding.rs b/src/tree/encoding.rs
index 8f2cbcda..a56cd379 100644
--- a/src/tree/encoding.rs
+++ b/src/tree/encoding.rs
@@ -88,7 +88,7 @@ mod tests {
         assert_eq!(
             tree.encode(),
             vec![
-                1, 1, 2, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
+                1, 0, 1, 2, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
                 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 123, 124, 0, 55, 55, 55,
                 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55,
                 55, 55, 55, 55, 55, 55, 55, 55, 1
@@ -113,7 +113,7 @@ mod tests {
         assert_eq!(
             tree.encode(),
             vec![
-                1, 1, 2, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
+                1, 0, 1, 2, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
                 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 123, 124, 0, 55, 55, 55,
                 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55,
                 55, 55, 55, 55, 55, 55, 55, 55, 1
@@ -139,7 +139,7 @@ mod tests {
         assert_eq!(
             tree.encode(),
             vec![
-                1, 1, 2, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
+                1, 0, 1, 2, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
                 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 123, 124, 0, 55, 55, 55,
                 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55,
                 55, 55, 55, 55, 55, 55, 55, 55, 1
@@ -161,7 +161,7 @@ mod tests {
     #[test]
     fn decode_reference_tree() {
         let bytes = vec![
-            1, 1, 2, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
+            1, 0, 1, 2, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
             66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 123, 124, 0, 55, 55, 55, 55, 55,
             55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55,
             55, 55, 55, 55, 55, 1,
diff --git a/src/tree/kv.rs b/src/tree/kv.rs
index 42382c9f..ff9eae89 100644
--- a/src/tree/kv.rs
+++ b/src/tree/kv.rs
@@ -11,6 +11,7 @@ use std::{
 //       field and value field.
 
 /// Contains a key/value pair, and the hash of the key/value pair.
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct KV {
     pub(super) key: Vec<u8>,
     pub(super) value: Vec<u8>,
diff --git a/src/tree/link.rs b/src/tree/link.rs
index 8ce8dde0..313c7322 100644
--- a/src/tree/link.rs
+++ b/src/tree/link.rs
@@ -10,6 +10,7 @@ use super::Tree;
 
 /// Represents a reference to a child tree node. Links may or may not contain
 /// the child's `Tree` instance (storing its key if not).
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Link {
     /// Represents a child tree node which has been pruned from memory, only
     /// retaining a reference to it (its key). The child node can always be
@@ -464,15 +465,29 @@ mod test {
         assert_eq!(
             bytes,
             vec![
-                3, 1, 2, 3, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55,
-                55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 123, 124
+                0, 3, 1, 2, 3, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55,
+                55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 123, 124
             ]
         );
     }
 
+    #[test]
+    fn encode_link_long_key_valid() {
+        let link = Link::Reference {
+            key: vec![123; 60_000],
+            child_heights: (123, 124),
+            hash: [55; 32],
+        };
+        let mut bytes = vec![];
+        link.encode_into(&mut bytes).unwrap();
+
+        let decoded = Link::decode(&bytes[..]).unwrap();
+        assert_eq!(decoded, link);
+    }
+
     #[test]
     #[should_panic = "Key length must be less than 65536"]
-    fn encode_link_long_key() {
+    fn encode_link_long_key_invalid() {
         let link = Link::Reference {
             key: vec![123; 70_000],
             child_heights: (123, 124),
diff --git a/src/tree/mod.rs b/src/tree/mod.rs
index fb6226cc..db9c3665 100644
--- a/src/tree/mod.rs
+++ b/src/tree/mod.rs
@@ -26,7 +26,7 @@ pub use walk::{Fetch, RefWalker, Walker};
 // relevant methods
 
 /// The fields of the `Tree` type, stored on the heap.
-#[derive(Encode, Decode)]
+#[derive(Debug, Clone, PartialEq, Eq, Encode, Decode)]
 pub struct TreeInner {
     left: Option<Link>,
     right: Option<Link>,
@@ -38,7 +38,7 @@ pub struct TreeInner {
 /// Trees' inner fields are stored on the heap so that nodes can recursively
 /// link to each other, and so we can detach nodes from their parents, then
 /// reattach without allocating or freeing heap memory.
-#[derive(Encode, Decode)]
+#[derive(Clone, PartialEq, Eq, Encode, Decode)]
 pub struct Tree {
     inner: Box<TreeInner>,
 }