From c2f28133857cb4cc7496b8dbe442cfb3cb5227ad Mon Sep 17 00:00:00 2001
From: ethDreamer <37123614+ethDreamer@users.noreply.github.com>
Date: Mon, 29 Nov 2021 18:56:49 -0600
Subject: [PATCH] Cleanup Comments & Fix get_pow_block_hash_at_ttd() (#2835)

---
 .../execution_layer/src/engine_api/http.rs    | 26 +---------------
 beacon_node/execution_layer/src/lib.rs        | 31 +++++++++----------
 2 files changed, 16 insertions(+), 41 deletions(-)

diff --git a/beacon_node/execution_layer/src/engine_api/http.rs b/beacon_node/execution_layer/src/engine_api/http.rs
index 51e0e123c..c4e7a71ae 100644
--- a/beacon_node/execution_layer/src/engine_api/http.rs
+++ b/beacon_node/execution_layer/src/engine_api/http.rs
@@ -624,18 +624,6 @@ mod test {
             .await
             .with_preloaded_responses(
                 // engine_forkchoiceUpdatedV1 (prepare payload) RESPONSE validation
-                //
-                // NOTE THIS HAD TO BE MODIFIED FROM ORIGINAL RESPONSE
-                // {
-                //      "jsonrpc":"2.0",
-                //      "id":67,
-                //      "result":{
-                //          "status":"VALID", // <- This must be SUCCESS
-                //          "payloadId":"0xa247243752eb10b4"
-                //      }
-                // }
-                // see spec for engine_forkchoiceUpdatedV1 response:
-                // https://github.com/ethereum/execution-apis/blob/v1.0.0-alpha.4/src/engine/specification.md#response-1
                 vec![json!({
                     "id": STATIC_ID,
                     "jsonrpc": JSONRPC_VERSION,
@@ -779,18 +767,6 @@ mod test {
             .await
             .with_preloaded_responses(
                 // engine_executePayloadV1 RESPONSE validation
-                //
-                // NOTE THIS HAD TO BE MODIFIED FROM ORIGINAL RESPONSE
-                // {
-                //      "jsonrpc":"2.0",
-                //      "id":67,
-                //      "result":{
-                //          "status":"SUCCESS", // <- This must be VALID
-                //          "latestValidHash":"0x3559e851470f6e7bbed1db474980683e8c315bfce99b2a6ef47c057c04de7858"
-                //      }
-                // }
-                // see spec for engine_executePayloadV1 response:
-                // https://github.com/ethereum/execution-apis/blob/v1.0.0-alpha.4/src/engine/specification.md#response
                 vec![json!({
                     "jsonrpc": JSONRPC_VERSION,
                     "id": STATIC_ID,
@@ -852,7 +828,7 @@ mod test {
                     "id": STATIC_ID,
                     "result": {
                         "status":"SUCCESS",
-                        "payloadId": serde_json::Value::Null
+                        "payloadId": JSON_NULL,
                     }
                 })],
                 |client| async move {
diff --git a/beacon_node/execution_layer/src/lib.rs b/beacon_node/execution_layer/src/lib.rs
index e322b815e..ec5d7e826 100644
--- a/beacon_node/execution_layer/src/lib.rs
+++ b/beacon_node/execution_layer/src/lib.rs
@@ -530,24 +530,23 @@ impl ExecutionLayer {
         // this implementation becomes canonical.
         loop {
             let block_reached_ttd = block.total_difficulty >= spec.terminal_total_difficulty;
-            if block_reached_ttd && block.parent_hash == Hash256::zero() {
-                return Ok(Some(block.block_hash));
-            } else if block.parent_hash == Hash256::zero() {
-                // The end of the chain has been reached without finding the TTD, there is no
-                // terminal block.
-                return Ok(None);
-            }
+            if block_reached_ttd {
+                if block.parent_hash == Hash256::zero() {
+                    return Ok(Some(block.block_hash));
+                }
+                let parent = self
+                    .get_pow_block(engine, block.parent_hash)
+                    .await?
+                    .ok_or(ApiError::ExecutionBlockNotFound(block.parent_hash))?;
+                let parent_reached_ttd = parent.total_difficulty >= spec.terminal_total_difficulty;
 
-            let parent = self
-                .get_pow_block(engine, block.parent_hash)
-                .await?
-                .ok_or(ApiError::ExecutionBlockNotFound(block.parent_hash))?;
-            let parent_reached_ttd = parent.total_difficulty >= spec.terminal_total_difficulty;
-
-            if block_reached_ttd && !parent_reached_ttd {
-                return Ok(Some(block.block_hash));
+                if block_reached_ttd && !parent_reached_ttd {
+                    return Ok(Some(block.block_hash));
+                } else {
+                    block = parent;
+                }
             } else {
-                block = parent;
+                return Ok(None);
             }
         }
     }