From e3b0edd397028741f7be061ef5b90b9b47dec762 Mon Sep 17 00:00:00 2001
From: Advaita Saha <adv11sphs@gmail.com>
Date: Fri, 4 Oct 2024 07:07:24 +0530
Subject: [PATCH] Fix nrpc edge cases (#2692)

* fix: engineAPI unable to connect

* fix: pre-merge situation
---
 nrpc/nrpc.nim | 34 ++++++++++++++++++----------------
 1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/nrpc/nrpc.nim b/nrpc/nrpc.nim
index 054f6ce72..27fd1af42 100644
--- a/nrpc/nrpc.nim
+++ b/nrpc/nrpc.nim
@@ -130,20 +130,18 @@ proc syncToEngineApi(conf: NRpcConf) {.async.} =
     # And exchange the capabilities for a test communication
     web3 = await engineUrl.newWeb3()
     rpcClient = web3.provider
-    data =
-      try:
-        await rpcClient.exchangeCapabilities(
-          @[
-            "engine_forkchoiceUpdatedV1",
-            "engine_getPayloadBodiesByHash", "engine_getPayloadBodiesByRangeV1",
-            "engine_getPayloadV1", "engine_newPayloadV1",
-          ]
-        )
-      except CatchableError as exc:
-        error "Error Connecting to the EL Engine API", error = exc.msg
-        @[]
 
-  notice "Communication with the EL Success", data = data
+  try:
+    let data = await rpcClient.exchangeCapabilities(
+      @[
+        "engine_forkchoiceUpdatedV1", "engine_getPayloadBodiesByHash",
+        "engine_getPayloadBodiesByRangeV1", "engine_getPayloadV1", "engine_newPayloadV1",
+      ]
+    )
+    notice "Communication with the EL Success", data = data
+  except CatchableError as exc:
+    error "Error Connecting to the EL Engine API", error = exc.msg
+    quit(QuitFailure)
 
   # Get the latest block number from the EL rest api
   template elBlockNumber(): uint64 =
@@ -163,6 +161,12 @@ proc syncToEngineApi(conf: NRpcConf) {.async.} =
 
   notice "Current block number", number = currentBlockNumber
 
+  # Check for pre-merge situation
+  if currentBlockNumber <= lastEra1Block:
+    notice "Pre-merge, nrpc syncer works post-merge",
+      blocknumber = currentBlockNumber, lastPoWBlock = lastEra1Block
+    quit(QuitSuccess)
+
   # Load the latest state from the CL
   var
     (finalizedBlck, _) = client.getELBlockFromBeaconChain(
@@ -216,9 +220,7 @@ proc syncToEngineApi(conf: NRpcConf) {.async.} =
           )
           debug "Making new payload call for Deneb"
           payloadResponse = await rpcClient.newPayload(
-            payload,
-            versioned_hashes,
-            forkyBlck.message.parent_root.to(Hash32),
+            payload, versioned_hashes, forkyBlck.message.parent_root.to(Hash32)
           )
         notice "Payload status", response = payloadResponse