feat(bot-oo): detect nonce backlog and exit early

Add detectNonceBacklog() helper to shared transactionClearing module.
bot-oo now checks for pending transactions before each iteration and
exits early if a backlog is detected to avoid compounding nonce issues.

Signed-off-by: Pablo Maldonado <pablo@umaproject.org>

Author: md0x

packages/monitor-v2/src/bot-oo/index.ts

@@ -1,6 +1,7 @@
 import { delay, waitForLogger, GasEstimator } from "@uma/financial-templates-lib";
 import { BotModes, initMonitoringParams, Logger, startupLogLevel } from "./common";
 import { settleRequests } from "./SettleRequests";
+import { detectNonceBacklog } from "../bot-utils/transactionClearing";
 
 const logger = Logger;
 
@@ -22,6 +23,19 @@ async function main() {
   };
 
   for (;;) {
+    // Check for nonce backlog before running settlements
+    const nonceStatus = await detectNonceBacklog(params.provider, params.signer);
+    if (nonceStatus.hasBacklog) {
+      logger.error({
+        at: "OracleBot",
+        message: "Nonce backlog detected, skipping settlements to avoid compounding issues",
+        latestNonce: nonceStatus.latestNonce,
+        pendingNonce: nonceStatus.pendingNonce,
+        backlog: nonceStatus.backlog,
+      });
+      break;
+    }
+
     await gasEstimator.update();
 
     const runCmds = Object.entries(cmds)

packages/monitor-v2/src/bot-utils/transactionClearing.ts

@@ -73,6 +73,29 @@ async function getNonces(provider: Provider, address: string): Promise<{ latestN
   return { latestNonce, pendingNonce };
 }
 
+export interface NonceBacklogStatus {
+  hasBacklog: boolean;
+  latestNonce: number;
+  pendingNonce: number;
+  backlog: number;
+}
+
+/**
+ * Detects if there's a nonce backlog (pending transactions that haven't been mined).
+ */
+export async function detectNonceBacklog(provider: Provider, signer: Signer): Promise<NonceBacklogStatus> {
+  const address = await signer.getAddress();
+  const { latestNonce, pendingNonce } = await getNonces(provider, address);
+  const backlog = pendingNonce - latestNonce;
+
+  return {
+    hasBacklog: backlog > 0,
+    latestNonce,
+    pendingNonce,
+    backlog,
+  };
+}
+
 /**
  * Clears stuck transactions by sending self-transactions with higher gas fees.
  * @returns true if a nonce backlog was detected and clearing was attempted