fix: make get account proof retrieve latest known state

CHANGELOG.md

@@ -15,6 +15,7 @@
 - Added support for caching mempool statistics in the block producer server ([#1388](https://github.com/0xMiden/miden-node/pull/1388)).
 - Added mempool statistics to the block producer status in the `miden-network-monitor` binary ([#1392](https://github.com/0xMiden/miden-node/pull/1392)).
 - Add `S` generic to `NullifierTree` to allow usage with `LargeSmt`s ([#1353](https://github.com/0xMiden/miden-node/issues/1353)).
+- Modify `AccountProofRequest` to retrieve the latest known state in case specified block number (or chain tip) does not contain account updates ([#1422](https://github.com/0xMiden/miden-node/issues/1422)).
 
 ### Fixes
 

crates/proto/src/generated/rpc_store.rs

@@ -20,6 +20,8 @@ pub struct AccountProofRequest {
     pub account_id: ::core::option::Option<super::account::AccountId>,
     /// Block at which we'd like to get this data. If present, must be close to the chain tip.
     /// If not present, data from the latest block will be returned.
+    /// If the specified block does not contain an update for the specified account,
+    /// the latest available data will be returned.
     #[prost(message, optional, tag = "2")]
     pub block_num: ::core::option::Option<super::blockchain::BlockNumber>,
     /// Request for additional account details; valid only for public accounts.

crates/store/src/db/mod.rs

@@ -408,7 +408,7 @@ impl Db {
             .await
     }
 
-    /// Loads account details at a specific block number from the DB.
+    /// Loads account details up to a specific block number from the DB.
     #[instrument(level = "debug", target = COMPONENT, skip_all, ret(level = "debug"), err)]
     pub async fn select_historical_account_at(
         &self,

crates/store/src/db/models/queries/accounts.rs

@@ -93,8 +93,7 @@ pub(crate) fn select_account(
     Ok(info)
 }
 
-/// Select account details at a specific block number from the DB using the given
-/// [`SqliteConnection`].
+/// Select account details as they are at the given block height.
 ///
 /// # Returns
 ///
@@ -118,7 +117,11 @@ pub(crate) fn select_account(
 ///     account_codes ON accounts.code_commitment = account_codes.code_commitment
 /// WHERE
 ///     account_id = ?1
-///     AND block_num = ?2
+///     AND block_num <= ?2
+/// ORDER BY
+///     block_num DESC
+/// LIMIT
+///     1
 /// ```
 pub(crate) fn select_historical_account_at(
     conn: &mut SqliteConnection,
@@ -134,8 +137,10 @@ pub(crate) fn select_historical_account_at(
     .filter(
         schema::accounts::account_id
             .eq(account_id.to_bytes())
-            .and(schema::accounts::block_num.eq(block_num.to_raw_sql())),
+            .and(schema::accounts::block_num.le(block_num.to_raw_sql())),
     )
+    .order_by(schema::accounts::block_num.desc())
+    .limit(1)
     .get_result::<(AccountRaw, Option<Vec<u8>>)>(conn)
     .optional()?
     .ok_or(DatabaseError::AccountNotFoundInDb(account_id))?;

crates/store/src/state.rs

@@ -921,7 +921,7 @@ impl State {
     /// Returns the respective account proof with optional details, such as asset and storage
     /// entries.
     ///
-    /// When `block_num` is provided, this method will return the account state at that specific
+    /// When `block_num` is provided, this method will return the account state up to that specific
     /// block using both the historical account tree witness and historical database state.
     pub async fn get_account_proof(
         &self,
@@ -977,7 +977,7 @@ impl State {
         Ok((block_num, witness))
     }
 
-    /// Fetches the account details (code, vault, storage) for a public account at the specified
+    /// Fetches the account details (code, vault, storage) for a public account up to the specified
     /// block.
     ///
     /// This method queries the database to fetch the account state and processes the detail

proto/proto/store/rpc.proto

@@ -149,6 +149,8 @@ message AccountProofRequest {
 
     // Block at which we'd like to get this data. If present, must be close to the chain tip.
     // If not present, data from the latest block will be returned.
+    // If the specified block does not contain an update for the specified account,
+    // the latest available data will be returned.
     optional blockchain.BlockNumber block_num = 2;
 
     // Request for additional account details; valid only for public accounts.