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tx-pool/src/process.rs

@@ -428,14 +428,17 @@ impl TxPoolService {
         let orphan = self.orphan.read().await;
         let ids = orphan.find_by_previous(tx);
         ids.iter()
-            .map(|id| orphan.get(id).cloned().unwrap())
+            .filter_map(|id| orphan.get(id).cloned())
             .collect::<Vec<_>>()
     }
 
     pub(crate) async fn remove_orphan_tx(&self, id: &ProposalShortId) {
         self.orphan.write().await.remove_orphan_tx(id);
     }
 
+    /// Remove all orphans which are resolved by the given transaction
+    /// the process is like a breath first search, if there is a cycle in `orphan_queue`,
+    /// `_process_tx` will return `Reject` since we have checked duplicated tx
     pub(crate) async fn process_orphan_tx(&self, tx: &TransactionView) {
         let mut orphan_queue: VecDeque<TransactionView> = VecDeque::new();
         orphan_queue.push_back(tx.clone());