From aa7d0dd773061387923ea047e9afe460281ccb73 Mon Sep 17 00:00:00 2001
From: 0xPatrick <patrick@0xpatrick.dev>
Date: Wed, 6 Nov 2024 20:45:00 -0500
Subject: [PATCH] feat: `StatusManager` tracks `seenTxs`

- use a composite key of `txHash+chainId` to track unique `EventFeed` submissions
---
 packages/fast-usdc/src/exos/status-manager.js | 29 +++++++++++++++++--
 packages/fast-usdc/src/types.ts               |  3 ++
 .../test/exos/status-manager.test.ts          | 23 +++++++++++++++
 3 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/packages/fast-usdc/src/exos/status-manager.js b/packages/fast-usdc/src/exos/status-manager.js
index f76823917f7d..b0ba21ef9d07 100644
--- a/packages/fast-usdc/src/exos/status-manager.js
+++ b/packages/fast-usdc/src/exos/status-manager.js
@@ -6,9 +6,9 @@ import { CctpTxEvidenceShape, PendingTxShape } from '../typeGuards.js';
 import { PendingTxStatus } from '../constants.js';
 
 /**
- * @import {MapStore} from '@agoric/store';
+ * @import {MapStore, SetStore} from '@agoric/store';
  * @import {Zone} from '@agoric/zone';
- * @import {CctpTxEvidence, NobleAddress, PendingTxKey, PendingTx} from '../types.js';
+ * @import {CctpTxEvidence, NobleAddress, SeenTxKey, PendingTxKey, PendingTx} from '../types.js';
  */
 
 /**
@@ -29,6 +29,15 @@ const getPendingTxKey = evidence => {
   return toPendingTxKey(forwardingAddress, amount);
 };
 
+/**
+ * Get the key for the seenTxs SetStore
+ * @param {CctpTxEvidence} evidence
+ */
+const getSeenKey = evidence => {
+  const { txHash, chainId } = evidence;
+  return /** @type {SeenTxKey} */ (JSON.stringify([txHash, chainId]));
+};
+
 /**
  * The `StatusManager` keeps track of Pending and Seen Transactions
  * via {@link PendingTxStatus} states, aiding in coordination between the `Advancer`
@@ -45,11 +54,27 @@ export const prepareStatusManager = zone => {
     valueShape: M.arrayOf(PendingTxShape),
   });
 
+  /** @type {SetStore<SeenTxKey>} */
+  const seenTxs = zone.setStore('SeenTxs', {
+    keyShape: M.string(),
+  });
+
   /**
+   * Ensures that `txHash+chainId` has not been processed
+   * and adds entry to `seenTxs` set.
+   *
+   * Also records the CctpTxEvidence and status in `pendingTxs`.
+   *
    * @param {CctpTxEvidence} evidence
    * @param {PendingTxStatus} status
    */
   const recordPendingTx = (evidence, status) => {
+    const seenKey = getSeenKey(evidence);
+    if (seenTxs.has(seenKey)) {
+      throw makeError(`Transaction already seen: ${q(seenKey)}`);
+    }
+    seenTxs.add(seenKey);
+
     appendToStoredArray(
       pendingTxs,
       getPendingTxKey(evidence),
diff --git a/packages/fast-usdc/src/types.ts b/packages/fast-usdc/src/types.ts
index 13be7ece1a2d..9a991deca2e1 100644
--- a/packages/fast-usdc/src/types.ts
+++ b/packages/fast-usdc/src/types.ts
@@ -32,4 +32,7 @@ export interface PendingTx extends CctpTxEvidence {
 /** composite of NobleAddress and transaction amount value */
 export type PendingTxKey = `"["${NobleAddress}",${bigint}]"`;
 
+/** composite of EvmHash and chainId */
+export type SeenTxKey = `"["${EvmHash}",${number}]"`;
+
 export type * from './constants.js';
diff --git a/packages/fast-usdc/test/exos/status-manager.test.ts b/packages/fast-usdc/test/exos/status-manager.test.ts
index dd6acc60d7c2..db84453110e9 100644
--- a/packages/fast-usdc/test/exos/status-manager.test.ts
+++ b/packages/fast-usdc/test/exos/status-manager.test.ts
@@ -35,6 +35,29 @@ test('observe creates new entry with OBSERVED status', t => {
   t.is(entries[0]?.status, PendingTxStatus.Observed);
 });
 
+test('cannot process same tx twice', t => {
+  const zone = provideDurableZone('status-test');
+  const statusManager = prepareStatusManager(zone.subZone('status-manager'));
+
+  const evidence = MockCctpTxEvidences.AGORIC_PLUS_OSMO();
+  statusManager.advance(evidence);
+
+  t.throws(() => statusManager.advance(evidence), {
+    message:
+      'Transaction already seen: "[[\\"0xc81bc6105b60a234c7c50ac17816ebcd5561d366df8bf3be59ff387552761702\\",1]]"',
+  });
+
+  t.throws(() => statusManager.observe(evidence), {
+    message:
+      'Transaction already seen: "[[\\"0xc81bc6105b60a234c7c50ac17816ebcd5561d366df8bf3be59ff387552761702\\",1]]"',
+  });
+
+  // new txHash should not throw
+  t.notThrows(() => statusManager.advance({ ...evidence, txHash: '0xtest2' }));
+  // new chainId with existing txHash should not throw
+  t.notThrows(() => statusManager.advance({ ...evidence, chainId: 9999 }));
+});
+
 test('settle removes entries from PendingTxs', t => {
   const zone = provideDurableZone('status-test');
   const statusManager = prepareStatusManager(zone.subZone('status-manager'));