Merge pull request #3785 from mempool/mononaut/mined-block-rbf

Detect RBF by mined transactions

backend/src/api/common.ts

@@ -77,6 +77,24 @@ export class Common {
     return matches;
   }
 
+  static findMinedRbfTransactions(minedTransactions: TransactionExtended[], spendMap: Map<string, TransactionExtended>): { [txid: string]: { replaced: TransactionExtended[], replacedBy: TransactionExtended }} {
+    const matches: { [txid: string]: { replaced: TransactionExtended[], replacedBy: TransactionExtended }} = {};
+    for (const tx of minedTransactions) {
+      const replaced: Set<TransactionExtended> = new Set();
+      for (let i = 0; i < tx.vin.length; i++) {
+        const vin = tx.vin[i];
+        const match = spendMap.get(`${vin.txid}:${vin.vout}`);
+        if (match && match.txid !== tx.txid) {
+          replaced.add(match);
+        }
+      }
+      if (replaced.size) {
+        matches[tx.txid] = { replaced: Array.from(replaced), replacedBy: tx };
+      }
+    }
+    return matches;
+  }
+
   static stripTransaction(tx: TransactionExtended): TransactionStripped {
     return {
       txid: tx.txid,

backend/src/api/mempool.ts

@@ -14,6 +14,7 @@ class Mempool {
   private inSync: boolean = false;
   private mempoolCacheDelta: number = -1;
   private mempoolCache: { [txId: string]: TransactionExtended } = {};
+  private spendMap = new Map<string, TransactionExtended>();
   private mempoolInfo: IBitcoinApi.MempoolInfo = { loaded: false, size: 0, bytes: 0, usage: 0, total_fee: 0,
                                                     maxmempool: 300000000, mempoolminfee: 0.00001000, minrelaytxfee: 0.00001000 };
   private mempoolChangedCallback: ((newMempool: {[txId: string]: TransactionExtended; }, newTransactions: TransactionExtended[],
@@ -77,6 +78,10 @@ class Mempool {
     return this.mempoolCache;
   }
 
+  public getSpendMap(): Map<string, TransactionExtended> {
+    return this.spendMap;
+  }
+
   public async $setMempool(mempoolData: { [txId: string]: TransactionExtended }) {
     this.mempoolCache = mempoolData;
     if (this.mempoolChangedCallback) {
@@ -85,6 +90,7 @@ class Mempool {
     if (this.$asyncMempoolChangedCallback) {
       await this.$asyncMempoolChangedCallback(this.mempoolCache, [], []);
     }
+    this.addToSpendMap(Object.values(this.mempoolCache));
   }
 
   public async $updateMemPoolInfo() {
@@ -276,6 +282,34 @@ class Mempool {
     }
   }
 
+  public handleMinedRbfTransactions(rbfTransactions: { [txid: string]: { replaced: TransactionExtended[], replacedBy: TransactionExtended }}): void {
+    for (const rbfTransaction in rbfTransactions) {
+      if (rbfTransactions[rbfTransaction].replacedBy && rbfTransactions[rbfTransaction]?.replaced?.length) {
+        // Store replaced transactions
+        rbfCache.add(rbfTransactions[rbfTransaction].replaced, rbfTransactions[rbfTransaction].replacedBy);
+      }
+    }
+  }
+
+  public addToSpendMap(transactions: TransactionExtended[]): void {
+    for (const tx of transactions) {
+      for (const vin of tx.vin) {
+        this.spendMap.set(`${vin.txid}:${vin.vout}`, tx);
+      }
+    }
+  }
+
+  public removeFromSpendMap(transactions: TransactionExtended[]): void {
+    for (const tx of transactions) {
+      for (const vin of tx.vin) {
+        const key = `${vin.txid}:${vin.vout}`;
+        if (this.spendMap.get(key)?.txid === tx.txid) {
+          this.spendMap.delete(key);
+        }
+      }
+    }
+  }
+
   private updateTxPerSecond() {
     const nowMinusTimeSpan = new Date().getTime() - (1000 * config.STATISTICS.TX_PER_SECOND_SAMPLE_PERIOD);
     this.txPerSecondArray = this.txPerSecondArray.filter((unixTime) => unixTime > nowMinusTimeSpan);

backend/src/api/rbf-cache.ts

@@ -31,7 +31,7 @@ class RbfCache {
   }
 
   public add(replaced: TransactionExtended[], newTxExtended: TransactionExtended): void {
-    if (!newTxExtended || !replaced?.length) {
+    if (!newTxExtended || !replaced?.length || this.txs.has(newTxExtended.txid)) {
       return;
     }
 

backend/src/api/websocket-handler.ts

@@ -332,6 +332,8 @@ class WebsocketHandler {
     for (const deletedTx of deletedTransactions) {
       rbfCache.evict(deletedTx.txid);
     }
+    memPool.removeFromSpendMap(deletedTransactions);
+    memPool.addToSpendMap(newTransactions);
     const recommendedFees = feeApi.getRecommendedFee();
 
     // update init data
@@ -600,6 +602,10 @@ class WebsocketHandler {
       }
     }
 
+    const rbfTransactions = Common.findMinedRbfTransactions(transactions, memPool.getSpendMap());
+    memPool.handleMinedRbfTransactions(rbfTransactions);
+    memPool.removeFromSpendMap(transactions);
+
     // Update mempool to remove transactions included in the new block
     for (const txId of txIds) {
       delete _memPool[txId];