From 900e66aef7aee9329c7bccc60a5d7eb1907d4176 Mon Sep 17 00:00:00 2001
From: Mononaut <github@monospace.live>
Date: Thu, 2 Feb 2023 17:37:32 -0600
Subject: [PATCH] More robust error checking & handling in CPFP repositories

---
 backend/src/repositories/CpfpRepository.ts    | 46 +++++++++++--------
 .../src/repositories/TransactionRepository.ts | 34 +++++++-------
 2 files changed, 43 insertions(+), 37 deletions(-)

diff --git a/backend/src/repositories/CpfpRepository.ts b/backend/src/repositories/CpfpRepository.ts
index ce7432d5b..9d8b2fe75 100644
--- a/backend/src/repositories/CpfpRepository.ts
+++ b/backend/src/repositories/CpfpRepository.ts
@@ -111,7 +111,7 @@ class CpfpRepository {
     }
   }
 
-  public async $getCluster(clusterRoot: string): Promise<Cluster> {
+  public async $getCluster(clusterRoot: string): Promise<Cluster | void> {
     const [clusterRows]: any = await DB.query(
       `
         SELECT *
@@ -121,8 +121,11 @@ class CpfpRepository {
       [clusterRoot]
     );
     const cluster = clusterRows[0];
-    cluster.txs = this.unpack(cluster.txs);
-    return cluster;
+    if (cluster?.txs) {
+      cluster.txs = this.unpack(cluster.txs);
+      return cluster;
+    }
+    return;
   }
 
   public async $deleteClustersFrom(height: number): Promise<void> {
@@ -136,9 +139,9 @@ class CpfpRepository {
         [height]
       ) as RowDataPacket[][];
       if (rows?.length) {
-        for (let clusterToDelete of rows) {
-          const txs = this.unpack(clusterToDelete.txs);
-          for (let tx of txs) {
+        for (const clusterToDelete of rows) {
+          const txs = this.unpack(clusterToDelete?.txs);
+          for (const tx of txs) {
             await transactionRepository.$removeTransaction(tx.txid);
           }
         }
@@ -204,20 +207,25 @@ class CpfpRepository {
       return [];
     }
 
-    const arrayBuffer = buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
-    const txs: Ancestor[] = [];
-    const view = new DataView(arrayBuffer);
-    for (let offset = 0; offset < arrayBuffer.byteLength; offset += 44) {
-      const txid = Array.from(new Uint8Array(arrayBuffer, offset, 32)).reverse().map(b => b.toString(16).padStart(2, '0')).join('');
-      const weight = view.getUint32(offset + 32);
-      const fee = Number(view.getBigUint64(offset + 36));
-      txs.push({
-        txid,
-        weight,
-        fee
-      });
+    try {
+      const arrayBuffer = buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
+      const txs: Ancestor[] = [];
+      const view = new DataView(arrayBuffer);
+      for (let offset = 0; offset < arrayBuffer.byteLength; offset += 44) {
+        const txid = Array.from(new Uint8Array(arrayBuffer, offset, 32)).reverse().map(b => b.toString(16).padStart(2, '0')).join('');
+        const weight = view.getUint32(offset + 32);
+        const fee = Number(view.getBigUint64(offset + 36));
+        txs.push({
+          txid,
+          weight,
+          fee
+        });
+      }
+      return txs;
+    } catch (e) {
+      logger.warn(`Failed to unpack CPFP cluster. Reason: ` + (e instanceof Error ? e.message : e));
+      return [];
     }
-    return txs;
   }
 }
 
diff --git a/backend/src/repositories/TransactionRepository.ts b/backend/src/repositories/TransactionRepository.ts
index 061617451..279a2bdad 100644
--- a/backend/src/repositories/TransactionRepository.ts
+++ b/backend/src/repositories/TransactionRepository.ts
@@ -3,15 +3,6 @@ import logger from '../logger';
 import { Ancestor, CpfpInfo } from '../mempool.interfaces';
 import cpfpRepository from './CpfpRepository';
 
-interface CpfpSummary {
-  txid: string;
-  cluster: string;
-  root: string;
-  txs: Ancestor[];
-  height: number;
-  fee_rate: number;
-}
-
 class TransactionRepository {
   public async $setCluster(txid: string, clusterRoot: string): Promise<void> {
     try {
@@ -72,7 +63,9 @@ class TransactionRepository {
         const txid = txRows[0].id.toLowerCase();
         const clusterId = txRows[0].root.toLowerCase();
         const cluster = await cpfpRepository.$getCluster(clusterId);
-        return this.convertCpfp(txid, cluster);
+        if (cluster) {
+          return this.convertCpfp(txid, cluster);
+        }
       }
     } catch (e) {
       logger.err('Cannot get transaction cpfp info from db. Reason: ' + (e instanceof Error ? e.message : e));
@@ -81,13 +74,18 @@ class TransactionRepository {
   }
 
   public async $removeTransaction(txid: string): Promise<void> {
-    await DB.query(
-      `
-        DELETE FROM compact_transactions
-        WHERE txid = UNHEX(?)
-      `,
-      [txid]
-    );
+    try {
+      await DB.query(
+        `
+          DELETE FROM compact_transactions
+          WHERE txid = UNHEX(?)
+        `,
+        [txid]
+      );
+    } catch (e) {
+      logger.warn('Cannot delete transaction cpfp info from db. Reason: ' + (e instanceof Error ? e.message : e));
+      throw e;
+    }
   }
 
   private convertCpfp(txid, cluster): CpfpInfo {
@@ -95,7 +93,7 @@ class TransactionRepository {
     const ancestors: Ancestor[] = [];
     let matched = false;
 
-    for (const tx of cluster.txs) {
+    for (const tx of (cluster?.txs || [])) {
       if (tx.txid === txid) {
         matched = true;
       } else if (!matched) {