added locks to advance block and broadcast endpoints

Author: Roee-87

src/rest/mod.rs

@@ -62,6 +62,8 @@ pub struct Rest<N: Network, C: ConsensusStorage<N>> {
     manual_block_creation: bool,
     /// The Private Key used for block creation.
     private_key: PrivateKey<N>,
+    /// Serializes all prepare+advance ledger operations to prevent concurrent block creation races.
+    block_creation_lock: Arc<Mutex<()>>,
     /// Sender half of the shutdown channel; consumed on first use.
     shutdown_tx: Arc<Mutex<Option<oneshot::Sender<()>>>>,
     /// Path to the ledger storage directory; None when running in-memory.
@@ -87,6 +89,7 @@ impl<N: Network, C: 'static + ConsensusStorage<N>> Rest<N, C> {
             num_verifying_executions: Default::default(),
             manual_block_creation,
             private_key,
+            block_creation_lock: Default::default(),
             shutdown_tx: Default::default(),
             storage_path,
         };

src/rest/routes.rs

@@ -528,6 +528,7 @@ impl<N: Network, C: ConsensusStorage<N>> Rest<N, C> {
             // Prepare and advance in a single blocking task to prevent concurrent broadcasts
             // from both preparing a block at the same height and racing to advance the ledger.
             tokio::task::spawn_blocking(move || {
+                let _guard = rest.block_creation_lock.lock();
                 let new_block = rest
                     .ledger
                     .prepare_advance_to_next_beacon_block(
@@ -659,6 +660,7 @@ impl<N: Network, C: ConsensusStorage<N>> Rest<N, C> {
         // Iterate and create the specified number of blocks.
         // Return the last created block.
         let last_block = tokio::task::spawn_blocking(move || -> Result<ErasedJson, RestError> {
+            let _guard = rest.block_creation_lock.lock();
             let mut last_block = None;
 
             // Take all unconfirmed transactions from the buffer.