fix(mempool): check exsit before insert a transaction (#257)

* fix: check exsit before insert transaction

* cargo fmt

* cargo fmt

core/mempool/src/map.rs

@@ -93,8 +93,16 @@ impl<V> Bucket<V>
 where
     V: Send + Sync + Clone,
 {
+    /// Before inserting a transaction into the bucket, you must check whether
+    /// the transaction is in the bucket first. Never use the insert function to
+    /// check this.
     fn insert(&self, hash: Hash, value: V) -> Option<V> {
-        self.store.write().insert(hash, value)
+        let mut lock_data = self.store.write();
+        if lock_data.contains_key(&hash) {
+            Some(value)
+        } else {
+            lock_data.insert(hash, value)
+        }
     }
 
     fn contains_key(&self, hash: &Hash) -> bool {

core/mempool/src/tx_cache.rs

@@ -526,7 +526,7 @@ mod tests {
         let tx_wrapper_1 = TxWrapper::new(tx.clone());
         map.insert(tx.tx_hash.clone(), Arc::new(tx_wrapper_1));
         let shared_tx_1 = map.get(&tx.tx_hash).unwrap();
-        assert!(!shared_tx_1.is_removed());
+        assert!(shared_tx_1.is_removed());
     }
 
     #[bench]