From e3e83b7e71c7d9f6a34b9d7b407b72ca3eda9b4e Mon Sep 17 00:00:00 2001
From: Roman Krasiuk <rokrassyuk@gmail.com>
Date: Thu, 17 Oct 2024 10:03:25 +0200
Subject: [PATCH] docs(trie): revealed sparse trie invariants (#11825)

---
 crates/trie/sparse/src/trie.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/crates/trie/sparse/src/trie.rs b/crates/trie/sparse/src/trie.rs
index 2edaaf76b2..d8f4280e87 100644
--- a/crates/trie/sparse/src/trie.rs
+++ b/crates/trie/sparse/src/trie.rs
@@ -69,6 +69,13 @@ impl SparseTrie {
 }
 
 /// The representation of revealed sparse trie.
+///
+/// ## Invariants
+///
+/// - The root node is always present in `nodes` collection.
+/// - Each leaf entry in `nodes` collection must have a corresponding entry in `values` collection.
+///   The opposite is also true.
+/// - All keys in `values` collection are full leaf paths.
 #[derive(PartialEq, Eq)]
 pub struct RevealedSparseTrie {
     /// All trie nodes.