fix: proper handling of old batches on Arbitrum Nova (#10786)

* AnyTrust old certificates support

* proper calculation the block range size

* don't exclude the block 0 from the boundaries search

apps/indexer/lib/indexer/fetcher/arbitrum/da/anytrust.ex

@@ -124,6 +124,25 @@ defmodule Indexer.Fetcher.Arbitrum.DA.Anytrust do
      }}
   end
 
+  def parse_batch_accompanying_data(batch_number, <<
+        keyset_hash::binary-size(32),
+        data_hash::binary-size(32),
+        timeout::big-unsigned-integer-size(64),
+        signers_mask::big-unsigned-integer-size(64),
+        bls_signature::binary-size(96)
+      >>) do
+    # https://github.com/OffchainLabs/nitro/blob/ad9ab00723e13cf98307b9b65774ad455594ef7b/arbstate/das_reader.go#L95-L151
+    {:ok, :in_anytrust,
+     %__MODULE__{
+       batch_number: batch_number,
+       keyset_hash: keyset_hash,
+       data_hash: data_hash,
+       timeout: IndexerHelper.timestamp_to_datetime(timeout),
+       signers_mask: signers_mask,
+       bls_signature: bls_signature
+     }}
+  end
+
   def parse_batch_accompanying_data(_, _) do
     log_error("Can not parse Anytrust DA message.")
     {:error, nil, nil}

apps/indexer/lib/indexer/fetcher/arbitrum/da/common.ex

@@ -124,8 +124,7 @@ defmodule Indexer.Fetcher.Arbitrum.DA.Common do
         {:error, nil, nil}
 
       128 ->
-        log_error("DAS messages are not supported.")
-        {:error, nil, nil}
+        Anytrust.parse_batch_accompanying_data(batch_number, rest)
 
       136 ->
         Anytrust.parse_batch_accompanying_data(batch_number, rest)

apps/indexer/lib/indexer/fetcher/arbitrum/utils/rpc.ex

@@ -646,7 +646,9 @@ defmodule Indexer.Fetcher.Arbitrum.Utils.Rpc do
       # inspected block is in the boundary of the required batch: the current batch is the same
       # as one found in the previous iteration or the step is not the smallest possible.
 
-      next_block_to_inspect = max(1, inspected_block - new_step)
+      # it is OK to use the earliest block 0 as since the corresponding batch (0)
+      # will be returned by get_batch_number_for_rollup_block.
+      next_block_to_inspect = max(0, inspected_block - new_step)
 
       do_binary_search_of_opposite_block(
         next_block_to_inspect,

apps/indexer/lib/indexer/fetcher/arbitrum/workers/new_batches.ex

@@ -1275,7 +1275,7 @@ defmodule Indexer.Fetcher.Arbitrum.Workers.NewBatches do
         {nil, nil}
 
       %Arbitrum.L1Batch{start_block: start_block, end_block: end_block} ->
-        {start_block - 1, div(end_block - start_block, 2)}
+        {start_block - 1, half_of_block_range(start_block, end_block, :descending)}
     end
   end
 
@@ -1289,7 +1289,26 @@ defmodule Indexer.Fetcher.Arbitrum.Workers.NewBatches do
         {nil, nil}
 
       %Arbitrum.L1Batch{start_block: start_block, end_block: end_block} ->
-        {end_block + 1, div(start_block - end_block, 2)}
+        {end_block + 1, half_of_block_range(start_block, end_block, :ascending)}
+    end
+  end
+
+  # Calculates half the range between two block numbers, with direction adjustment.
+  #
+  # ## Parameters
+  # - `start_block`: The starting block number.
+  # - `end_block`: The ending block number.
+  # - `direction`: The direction of calculation, either `:ascending` or `:descending`.
+  #
+  # ## Returns
+  # - An integer representing half the block range, adjusted for direction:
+  #   - For `:descending`, a positive integer >= 1.
+  #   - For `:ascending`, a negative integer <= -1.
+  @spec half_of_block_range(non_neg_integer(), non_neg_integer(), :ascending | :descending) :: integer()
+  defp half_of_block_range(start_block, end_block, direction) do
+    case direction do
+      :descending -> max(div(end_block - start_block + 1, 2), 1)
+      :ascending -> min(div(start_block - end_block - 1, 2), -1)
     end
   end