From 6342aedba3633bc309b156ba942c9d34681ef6c0 Mon Sep 17 00:00:00 2001
From: jsy1218 <91580504+jsy1218@users.noreply.github.com>
Date: Wed, 30 Oct 2024 18:35:36 -0400
Subject: [PATCH 1/2] fix: return a new tenderly simulation status in case of
 tenderly downtime

---
 src/providers/simulation-provider.ts          | 1 +
 src/providers/tenderly-simulation-provider.ts | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/providers/simulation-provider.ts b/src/providers/simulation-provider.ts
index 4b6127a43..4ae6e1aec 100644
--- a/src/providers/simulation-provider.ts
+++ b/src/providers/simulation-provider.ts
@@ -31,6 +31,7 @@ export enum SimulationStatus {
   Succeeded = 2,
   InsufficientBalance = 3,
   NotApproved = 4,
+  SystemDown = 5,
 }
 
 /**
diff --git a/src/providers/tenderly-simulation-provider.ts b/src/providers/tenderly-simulation-provider.ts
index 63eea56ef..680cabe60 100644
--- a/src/providers/tenderly-simulation-provider.ts
+++ b/src/providers/tenderly-simulation-provider.ts
@@ -223,7 +223,7 @@ export class FallbackTenderlySimulator extends Simulator {
           MetricLoggerUnit.Count
         );
       }
-      return { ...swapRoute, simulationStatus: SimulationStatus.Failed };
+      return { ...swapRoute, simulationStatus: SimulationStatus.SystemDown };
     }
   }
 }
@@ -440,6 +440,12 @@ export class TenderlySimulator extends Simulator {
           1,
           MetricLoggerUnit.Count
         );
+        // technically, we can also early return SimulationStatus.SystemDown when http status is not 200.
+        // in reality, when tenderly is down for whatever reason, i see it always throw during axios http request
+        // so that it hits the catch block in https://github.com/Uniswap/smart-order-router/blob/8bfec299001d3204483f761f57a38be04512a948/src/providers/tenderly-simulation-provider.ts#L226
+        // which is where we want to actually return SimulationStatus.SystemDown
+        // in other words, I've never see a TenderlySimulationUniversalRouterResponseStatus metric with a non-200 status
+        // if there's downtime, it won't log metric at https://github.com/Uniswap/smart-order-router/blob/8bfec299001d3204483f761f57a38be04512a948/src/providers/tenderly-simulation-provider.ts#L434
 
         // Validate tenderly response body
         if (

From 2bf9abf2137e2b255fd7b25bdd257b3e98505bb5 Mon Sep 17 00:00:00 2001
From: jsy1218 <91580504+jsy1218@users.noreply.github.com>
Date: Thu, 31 Oct 2024 12:48:33 -0400
Subject: [PATCH 2/2] fix: unit test assertion

---
 test/unit/providers/simulation-provider.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/unit/providers/simulation-provider.test.ts b/test/unit/providers/simulation-provider.test.ts
index 6b0f469c6..0b201117a 100644
--- a/test/unit/providers/simulation-provider.test.ts
+++ b/test/unit/providers/simulation-provider.test.ts
@@ -270,7 +270,7 @@ describe('Fallback Tenderly simulator', () => {
     );
     expect(tenderlySimulator.simulateTransaction.called).toBeTruthy();
     expect(swapRouteWithGasEstimate.simulationStatus).toEqual(
-      SimulationStatus.Failed
+      SimulationStatus.SystemDown
     );
   });
   test('when eth estimate gas simulator throws, try tenderly anyway', async () => {