feat: StatusManager tracks seenTxs

- use a composite key of `txHash+chainId` to track unique `EventFeed` submissions

Author: 0xpatrickdev

packages/fast-usdc/src/exos/status-manager.js

@@ -6,9 +6,9 @@ import { CctpTxEvidenceShape, PendingTxShape } from '../typeGuards.js';
 import { TxStatus } 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 +29,16 @@ const getPendingTxKey = evidence => {
   return toPendingTxKey(forwardingAddress, amount);
 };
 
+/**
+ * Get the key for the seenTxs SetStore
+ * @param {CctpTxEvidence} evidence
+ * @returns {SeenTxKey}
+ */
+const getSeenKey = evidence => {
+  const { txHash, chainId } = evidence;
+  return `${txHash}+${chainId}`;
+};
+
 /**
  * The `StatusManager` keeps track of Pending and Seen Transactions
  * via {@link TxStatus} states, aiding in coordination between the `Advancer`
@@ -45,6 +55,25 @@ 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 `txHash+chainId` to `seenTxs` set.
+   *
+   * @param {CctpTxEvidence} evidence
+   */
+  const assertNotSeen = evidence => {
+    const seenKey = getSeenKey(evidence);
+    if (seenTxs.has(seenKey)) {
+      throw makeError(`Transaction already seen: ${q(seenKey)}`);
+    }
+    seenTxs.add(seenKey);
+  };
+
   return zone.exo(
     'Fast USDC Status Manager',
     M.interface('StatusManagerI', {
@@ -60,6 +89,7 @@ export const prepareStatusManager = zone => {
        * @param {CctpTxEvidence} evidence
        */
       advance(evidence) {
+        assertNotSeen(evidence);
         const key = getPendingTxKey(evidence);
         const entry = { ...evidence, status: TxStatus.Advanced };
 
@@ -76,6 +106,7 @@ export const prepareStatusManager = zone => {
        * @param {CctpTxEvidence} evidence
        */
       observe(evidence) {
+        assertNotSeen(evidence);
         const key = getPendingTxKey(evidence);
         const entry = { ...evidence, status: TxStatus.Observed };
 

packages/fast-usdc/src/types.ts

@@ -32,4 +32,6 @@ export interface PendingTx extends CctpTxEvidence {
 /** composite of NobleAddress and transaction amount value */
 export type PendingTxKey = `"["${NobleAddress}",${bigint}]"`;
 
+export type SeenTxKey = `${EvmHash}+${number}`;
+
 export type * from './constants.js';