Fix review comments

client/api/src/backend.rs

@@ -53,8 +53,8 @@ pub trait Backend<Block: BlockT>: Send + Sync {
 		self.log_indexer().is_indexed()
 	}
 
-	/// Get the latest substrate block hash in the sql database.
-	async fn best_hash(&self) -> Result<Block::Hash, String>;
+	/// Get the hash of the latest substrate block fully indexed by the backend.
+	async fn latest_block_hash(&self) -> Result<Block::Hash, String>;
 }
 
 #[derive(Debug, Eq, PartialEq)]

client/db/src/kv/mod.rs

@@ -90,7 +90,7 @@ impl<Block: BlockT, C: HeaderBackend<Block>> fc_api::Backend<Block> for Backend<
 		&self.log_indexer
 	}
 
-	async fn best_hash(&self) -> Result<Block::Hash, String> {
+	async fn latest_block_hash(&self) -> Result<Block::Hash, String> {
 		Ok(self.client.info().best_hash)
 	}
 }

client/db/src/sql/mod.rs

@@ -866,8 +866,8 @@ impl<Block: BlockT<Hash = H256>> fc_api::Backend<Block> for Backend<Block> {
 		self
 	}
 
-	async fn best_hash(&self) -> Result<Block::Hash, String> {
-		// Retrieves the block hash for the latest indexed block, maybe it's not canon.
+	async fn latest_block_hash(&self) -> Result<Block::Hash, String> {
+		// Retrieves the block hash for the latestindexed block, maybe it's not canon.
 		sqlx::query("SELECT substrate_block_hash FROM blocks ORDER BY block_number DESC LIMIT 1")
 			.fetch_one(self.pool())
 			.await

client/rpc/src/lib.rs

@@ -210,10 +210,10 @@ pub mod frontier_backend_client {
 			BlockNumberOrHash::Num(number) => {
 				Ok(Some(BlockId::Number(number.unique_saturated_into())))
 			}
-			BlockNumberOrHash::Latest => match backend.best_hash().await {
+			BlockNumberOrHash::Latest => match backend.latest_block_hash().await {
 				Ok(hash) => Ok(Some(BlockId::Hash(hash))),
 				Err(e) => {
-					log::warn!(target: "rpc", "Failed to get best hash from the sql db: {:?}", e);
+					log::warn!(target: "rpc", "Failed to get latest block hash from the sql db: {:?}", e);
 					Ok(Some(BlockId::Hash(client.info().best_hash)))
 				}
 			},