From 8bd8ffe2bb3f7c8815ae9b52cc65927cfd1d12d6 Mon Sep 17 00:00:00 2001
From: Etan Kissling <etan@status.im>
Date: Tue, 12 Mar 2024 21:51:18 +0100
Subject: [PATCH] align default `syncHorizon` computation logic across networks
 (#6066)

The `syncHorizon` describes the number of empty slots before the beacon
node considers itself to be out of sync. There are two places where we
currently set this to 50 slots, but it makes more sense to base it on
wall time, e.g., the 10 minutes that the default 50 are derived from.
---
 beacon_chain/beacon_node.nim                              | 5 ++---
 beacon_chain/conf.nim                                     | 6 +++---
 beacon_chain/consensus_object_pools/consensus_manager.nim | 2 --
 beacon_chain/spec/beacon_time.nim                         | 3 +++
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/beacon_chain/beacon_node.nim b/beacon_chain/beacon_node.nim
index 49c7d327e..a3a08ce32 100644
--- a/beacon_chain/beacon_node.nim
+++ b/beacon_chain/beacon_node.nim
@@ -5,6 +5,8 @@
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
+{.push raises: [].}
+
 # Everything needed to run a full Beacon Node
 
 import
@@ -103,9 +105,6 @@ type
     processingDelay*: Opt[Duration]
     lastValidAttestedBlock*: Opt[BlockSlot]
 
-const
-  MaxEmptySlotCount* = uint64(10*60) div SECONDS_PER_SLOT
-
 # TODO stew/sequtils2
 template findIt*(s: openArray, predicate: untyped): int =
   var res = -1
diff --git a/beacon_chain/conf.nim b/beacon_chain/conf.nim
index 6cca45e9a..59b8aeb4c 100644
--- a/beacon_chain/conf.nim
+++ b/beacon_chain/conf.nim
@@ -586,9 +586,9 @@ type
 
       syncHorizon* {.
         hidden
-        desc: "Number of empty slots to process before considering the client out of sync"
-        defaultValue: MaxEmptySlotCount
-        defaultValueDesc: "50"
+        desc: "Number of empty slots to process before considering the client out of sync. Defaults to the number of slots in 10 minutes"
+        defaultValue: defaultSyncHorizon
+        defaultValueDesc: $defaultSyncHorizon
         name: "sync-horizon" .}: uint64
 
       terminalTotalDifficultyOverride* {.
diff --git a/beacon_chain/consensus_object_pools/consensus_manager.nim b/beacon_chain/consensus_object_pools/consensus_manager.nim
index acb63c14a..07100a2b6 100644
--- a/beacon_chain/consensus_object_pools/consensus_manager.nim
+++ b/beacon_chain/consensus_object_pools/consensus_manager.nim
@@ -278,8 +278,6 @@ func isSynced(dag: ChainDAGRef, wallSlot: Slot): bool =
   # the defaultSyncHorizon, it will start triggering in time so that potential
   # discrepancies between the head here, and the head the DAG has (which might
   # not yet be updated) won't be visible.
-  const defaultSyncHorizon = 50
-
   if dag.head.slot + defaultSyncHorizon < wallSlot:
     false
   else:
diff --git a/beacon_chain/spec/beacon_time.nim b/beacon_chain/spec/beacon_time.nim
index 19064e284..e165b59ad 100644
--- a/beacon_chain/spec/beacon_time.nim
+++ b/beacon_chain/spec/beacon_time.nim
@@ -278,3 +278,6 @@ chronicles.formatIt TimeDiff: it.shortLog
 chronicles.formatIt Slot: it.shortLog
 chronicles.formatIt Epoch: it.shortLog
 chronicles.formatIt SyncCommitteePeriod: it.shortLog
+
+const defaultSyncHorizon* =
+  (uint64(10*60) + SECONDS_PER_SLOT - 1) div SECONDS_PER_SLOT