Fix 500 response when ABI method was decoded as nil

.dialyzer-ignore

@@ -18,7 +18,7 @@ lib/phoenix/router.ex:402
 lib/block_scout_web/views/layout_view.ex:145: The call 'Elixir.Poison.Parser':'parse!'
 lib/block_scout_web/views/layout_view.ex:237: The call 'Elixir.Poison.Parser':'parse!'
 lib/block_scout_web/controllers/api/rpc/transaction_controller.ex:22
-lib/explorer/smart_contract/reader.ex:430
+lib/explorer/smart_contract/reader.ex:435
 lib/indexer/fetcher/token_total_supply_on_demand.ex:16
 lib/explorer/exchange_rates/source.ex:110
 lib/explorer/exchange_rates/source.ex:113

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Fixes
 - [#5025](https://github.com/blockscout/blockscout/pull/5025) - Add standard input JSON files validation
+- [#5051](https://github.com/blockscout/blockscout/pull/5051) - Fix 500 response when ABI method was parsed as nil
 
 ### Chore
 

apps/explorer/lib/explorer/smart_contract/reader.ex

@@ -299,8 +299,13 @@ defmodule Explorer.SmartContract.Reader do
     abi
     |> Enum.map(fn method ->
       parsed_method = [method] |> ABI.parse_specification() |> Enum.at(0)
-      method_id = Map.get(parsed_method, :method_id)
-      Map.put(method, "method_id", Base.encode16(method_id, case: :lower))
+
+      if is_map(parsed_method) do
+        method_id = Map.get(parsed_method, :method_id)
+        Map.put(method, "method_id", Base.encode16(method_id, case: :lower))
+      else
+        method
+      end
     end)
   end