fix: filter out incorrect L1-to-L2 Arbitrum messages (#10570)

apps/explorer/lib/explorer/chain/arbitrum/reader.ex

@@ -21,7 +21,11 @@ defmodule Explorer.Chain.Arbitrum.Reader do
   alias Explorer.Chain.Block, as: FullBlock
   alias Explorer.Chain.{Hash, Log, Transaction}
 
-  @to_l2_messages_transaction_types [100, 105]
+  # https://github.com/OffchainLabs/go-ethereum/blob/dff302de66598c36b964b971f72d35a95148e650/core/types/transaction.go#L44C2-L50
+  @message_to_l2_eth_deposit 100
+  @message_to_l2_submit_retryable_tx 105
+
+  @zero_wei 0
 
   @doc """
     Retrieves the number of the latest L1 block where an L1-to-L2 message was discovered.
@@ -834,6 +838,10 @@ defmodule Explorer.Chain.Arbitrum.Reader do
   # table. A message is considered missed if there is a transaction without a
   # matching message record.
   #
+  # For transactions that could be considered ETH deposits, it checks
+  # that the message value is not zero, as transactions with a zero value
+  # cannot be a deposit.
+  #
   # ## Returns
   #   - A query to retrieve missed L1-to-L2 messages.
   @spec missed_messages_to_l2_query() :: Ecto.Query.t()
@@ -841,7 +849,10 @@ defmodule Explorer.Chain.Arbitrum.Reader do
     from(rollup_tx in Transaction,
       left_join: msg in Message,
       on: rollup_tx.hash == msg.completion_transaction_hash and msg.direction == :to_l2,
-      where: rollup_tx.type in @to_l2_messages_transaction_types and is_nil(msg.completion_transaction_hash)
+      where:
+        (rollup_tx.type == ^@message_to_l2_submit_retryable_tx or
+           (rollup_tx.type == ^@message_to_l2_eth_deposit and rollup_tx.value != ^@zero_wei)) and
+          is_nil(msg.completion_transaction_hash)
     )
   end
 

apps/indexer/lib/indexer/fetcher/arbitrum/messaging.ex

@@ -62,10 +62,10 @@ defmodule Indexer.Fetcher.Arbitrum.Messaging do
   @doc """
     Filters a list of rollup transactions to identify L1-to-L2 messages and composes a map for each with the related message information.
 
-    This function filters through a list of rollup transactions, selecting those
-    with a non-nil `request_id`, indicating they are L1-to-L2 message completions.
-    These filtered transactions are then processed to construct a detailed message
-    structure for each.
+    This function filters a list of rollup transactions, selecting those where
+    `request_id` is not nil and is below 2^31, indicating they are L1-to-L2
+    message completions. These filtered transactions are then processed to
+    construct a detailed message structure for each.
 
     ## Parameters
     - `transactions`: A list of rollup transaction entries.
@@ -78,14 +78,14 @@ defmodule Indexer.Fetcher.Arbitrum.Messaging do
       this context are considered `:relayed` as they represent completed actions from
       L1 to L2.
   """
-  @spec filter_l1_to_l2_messages(maybe_improper_list(min_transaction, [])) :: [arbitrum_message]
-  @spec filter_l1_to_l2_messages(maybe_improper_list(min_transaction, []), boolean()) :: [arbitrum_message]
+  @spec filter_l1_to_l2_messages([min_transaction()]) :: [arbitrum_message]
+  @spec filter_l1_to_l2_messages([min_transaction()], boolean()) :: [arbitrum_message]
   def filter_l1_to_l2_messages(transactions, report \\ true)
       when is_list(transactions) and is_boolean(report) do
     messages =
       transactions
       |> Enum.filter(fn tx ->
-        tx[:request_id] != nil
+        tx[:request_id] != nil and Bitwise.bsr(tx[:request_id], 31) == 0
       end)
       |> handle_filtered_l1_to_l2_messages()
 

apps/indexer/lib/indexer/fetcher/arbitrum/workers/historical_messages_on_l2.ex

@@ -273,6 +273,8 @@ defmodule Indexer.Fetcher.Arbitrum.Workers.HistoricalMessagesOnL2 do
           messages ++ messages_acc
         end)
 
+      # Logging of zero messages is left by intent to reveal potential cases when
+      # not all transactions are recognized as completed L1-to-L2 messages.
       log_info("#{length(messages)} completions of L1-to-L2 messages will be imported")
       import_to_db(messages)
     end