populate dataColumnSidecarByRange with remote custody columns

beacon_chain/spec/eip7594_helpers.nim

@@ -31,10 +31,25 @@ proc sortedColumnIndices*(columnsPerSubnet: ColumnIndex, subnetIds: HashSet[uint
   for i in 0 ..< columnsPerSubnet:
     for subnetId in subnetIds:
       let index = DATA_COLUMN_SIDECAR_SUBNET_COUNT * i + subnetId
-      result.add(ColumnIndex(index))
+      res.add(ColumnIndex(index))
   res.sort()
   res
 
+proc sortedColumnIndexList*(columnsPerSubnet: ColumnIndex, 
+                          subnetIds: HashSet[uint64]): 
+                          List[ColumnIndex, NUMBER_OF_COLUMNS] =
+  var
+    res: seq[ColumnIndex]
+    list: List[ColumnIndex, NUMBER_OF_COLUMNS]
+  for i in 0 ..< columnsPerSubnet:
+    for subnetId in subnetIds:
+      let index = DATA_COLUMN_SIDECAR_SUBNET_COUNT * i + subnetId
+      res.add(ColumnIndex(index))
+  res.sort()
+  for elem in res:
+    discard list.add(ColumnIndex(elem))
+  list
+
 proc get_custody_column_subnet*(node_id: NodeId, 
                                 custody_subnet_count: uint64): 
                                 Result[HashSet[uint64], cstring] =
@@ -81,6 +96,17 @@ proc get_custody_columns*(node_id: NodeId,
   
   ok(sortedColumnIndices(ColumnIndex(columns_per_subnet), subnet_ids))
 
+proc get_custody_column_list*(node_id: NodeId, 
+                          custody_subnet_count: uint64): 
+                          Result[List[ColumnIndex, NUMBER_OF_COLUMNS], cstring] =
+    
+  let subnet_ids = get_custody_column_subnet(node_id, custody_subnet_count).get
+
+  # columns_per_subnet = NUMBER_OF_COLUMNS // DATA_COLUMN_SIDECAR_SUBNET_COUNT
+  let columns_per_subnet = NUMBER_OF_COLUMNS div DATA_COLUMN_SIDECAR_SUBNET_COUNT
+  
+  ok(sortedColumnIndexList(ColumnIndex(columns_per_subnet), subnet_ids))
+
 # https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.3/specs/_features/eip7594/das-core.md#compute_extended_matrix
 proc compute_extended_matrix* (blobs: seq[KzgBlob]): Result[seq[MatrixEntry], cstring] =
   # This helper demonstrates the relationship between blobs and the `MatrixEntries`

beacon_chain/sync/sync_manager.nim

@@ -280,9 +280,21 @@ proc getDataColumnSidecars[A, B](man: SyncManager[A, B], peer: A,
     direction = man.direction
     topics = "syncman"
   
+  let
+    remoteCustodySubnetCount =
+      if man.supernode:
+        DATA_COLUMN_SIDECAR_SUBNET_COUNT.uint64
+      else:
+        CUSTODY_REQUIREMENT.uint64
+
+  let
+    remoteNodeId = getNodeIdFromPeer(peer)
+    remoteCustodyColumns =
+      remoteNodeId.get_custody_column_list(remoteCustodySubnetCount).get
+
   doAssert(not(req.isEmpty()), "Request must not be empty!")
   debug "Requesting data column sidecars from peer", request = req
-  dataColumnSidecarsByRange(peer, req.slot, req.count, req.columns)
+  dataColumnSidecarsByRange(peer, req.slot, req.count, remoteCustodyColumns)
 
 func groupDataColumns*[T](req: SyncRequest[T],
                           blocks: seq[ref ForkedSignedBeaconBlock],

beacon_chain/sync/sync_queue.nim

@@ -38,7 +38,6 @@ type
     index*: uint64
     slot*: Slot
     count*: uint64
-    columns*: List[ColumnIndex, NUMBER_OF_COLUMNS]
     item*: T
 
   SyncResult*[T] = object